* [PATCH 0/2] asm qualifiers (PR55681) and asm input
@ 2018-10-30 18:01 Segher Boessenkool
2018-10-30 18:41 ` [PATCH 2/2] asm inline Segher Boessenkool
` (2 more replies)
0 siblings, 3 replies; 23+ messages in thread
From: Segher Boessenkool @ 2018-10-30 18:01 UTC (permalink / raw)
To: gcc-patches; +Cc: jakub, Segher Boessenkool
Hi!
This is the same "asm input" patch as before, but now preceded by a patch
that makes all orderings of volatile/goto/inline valid, also the other type
qualifiers for C, and also repetitions for C.
Tested on powerpc64-linux {-m32,-m64}. Is this okay for trunk?
Segher
gcc/c/c-parser.c | 79 ++++++++++++---------
gcc/c/c-tree.h | 3 +-
gcc/c/c-typeck.c | 3 +-
gcc/cp/cp-tree.h | 2 +-
gcc/cp/parser.c | 92 +++++++++++++++++--------
gcc/cp/pt.c | 2 +-
gcc/cp/semantics.c | 3 +-
gcc/doc/extend.texi | 10 ++-
gcc/gimple-pretty-print.c | 2 +
gcc/gimple.h | 24 ++++++-
gcc/gimplify.c | 1 +
gcc/ipa-icf-gimple.c | 3 +
gcc/testsuite/c-c++-common/torture/asm-inline.c | 53 ++++++++++++++
gcc/tree-core.h | 3 +
gcc/tree-inline.c | 3 +
gcc/tree.h | 3 +
16 files changed, 221 insertions(+), 65 deletions(-)
create mode 100644 gcc/testsuite/c-c++-common/torture/asm-inline.c
--
1.8.3.1
^ permalink raw reply [flat|nested] 23+ messages in thread* [PATCH 2/2] asm inline 2018-10-30 18:01 [PATCH 0/2] asm qualifiers (PR55681) and asm input Segher Boessenkool @ 2018-10-30 18:41 ` Segher Boessenkool 2018-10-30 18:58 ` Marek Polacek ` (2 more replies) 2018-10-30 18:56 ` [PATCH 1/2] asm qualifiers (PR55681) Segher Boessenkool 2018-11-11 0:33 ` [PATCH 0/2] asm qualifiers (PR55681) and asm input Segher Boessenkool 2 siblings, 3 replies; 23+ messages in thread From: Segher Boessenkool @ 2018-10-30 18:41 UTC (permalink / raw) To: gcc-patches; +Cc: jakub, Segher Boessenkool The Linux kernel people want a feature that makes GCC pretend some inline assembler code is tiny (while it would think it is huge), so that such code will be inlined essentially always instead of essentially never. This patch lets you say "asm inline" instead of just "asm", with the result that that inline assembler is always counted as minimum cost for inlining. It implements this for C and C++. 2018-10-30 Segher Boessenkool <segher@kernel.crashing.org> * doc/extend.texi (Using Assembly Language with C): Document asm inline. (Size of an asm): Fix typo. Document asm inline. * gimple-pretty-print.c (dump_gimple_asm): Handle asm inline. * gimple.h (enum gf_mask): Add GF_ASM_INLINE. (gimple_asm_set_volatile): Fix typo. * gimple_asm_inline_p: New. * gimple_asm_set_inline: New. * gimplify.c (gimplify_asm_expr): Propagate the asm inline flag from tree to gimple. * ipa-icf-gimple.c (func_checker::compare_gimple_asm): Compare the gimple_asm_inline_p flag, too. * tree-core.h (tree_base): Document that protected_flag is ASM_INLINE_P in an ASM_EXPR. * tree-inline.c (estimate_num_insns): If gimple_asm_inline_p return a minimum size for an asm. * tree.h (ASM_INLINE_P): New. gcc/c/ * c-parser.c (c_parser_asm_statement): Detect the inline keyword after asm. Pass a flag for it to build_asm_expr. * c-tree.h (build_asm_expr): Update declaration. * c-typeck.c (build_asm_stmt): Add is_inline parameter. Use it to set ASM_INLINE_P. gcc/cp/ * cp-tree.h (finish_asm_stmt): Update declaration. * parser.c (cp_parser_asm_definition): Detect the inline keyword after asm. Pass a flag for it to finish_asm_stmt. * pt.c (tsubst_expr): Pass the ASM_INLINE_P flag to finish_asm_stmt. * semantics.c (finish_asm_stmt): Add inline_p parameter. Use it to set ASM_INLINE_P. gcc/testsuite/ * c-c++-common/torture/asm-inline.c: New testcase. --- gcc/c/c-parser.c | 15 +++++-- gcc/c/c-tree.h | 3 +- gcc/c/c-typeck.c | 3 +- gcc/cp/cp-tree.h | 2 +- gcc/cp/parser.c | 15 ++++++- gcc/cp/pt.c | 2 +- gcc/cp/semantics.c | 3 +- gcc/doc/extend.texi | 10 ++++- gcc/gimple-pretty-print.c | 2 + gcc/gimple.h | 24 ++++++++++- gcc/gimplify.c | 1 + gcc/ipa-icf-gimple.c | 3 ++ gcc/testsuite/c-c++-common/torture/asm-inline.c | 53 +++++++++++++++++++++++++ gcc/tree-core.h | 3 ++ gcc/tree-inline.c | 3 ++ gcc/tree.h | 3 ++ 16 files changed, 133 insertions(+), 12 deletions(-) create mode 100644 gcc/testsuite/c-c++-common/torture/asm-inline.c diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c index ce9921e..b28b712 100644 --- a/gcc/c/c-parser.c +++ b/gcc/c/c-parser.c @@ -6283,11 +6283,12 @@ c_parser_for_statement (c_parser *parser, bool ivdep, unsigned short unroll, } /* Parse an asm statement, a GNU extension. This is a full-blown asm - statement with inputs, outputs, clobbers, and volatile and goto tag - allowed. + statement with inputs, outputs, clobbers, and volatile, inline, and goto + tags allowed. asm-qualifier: type-qualifier + inline goto asm-qualifier-list: @@ -6315,7 +6316,7 @@ static tree c_parser_asm_statement (c_parser *parser) { tree quals, str, outputs, inputs, clobbers, labels, ret; - bool simple, is_goto; + bool simple, is_inline, is_goto; location_t asm_loc = c_parser_peek_token (parser)->location; int section, nsections; @@ -6323,6 +6324,7 @@ c_parser_asm_statement (c_parser *parser) c_parser_consume_token (parser); quals = NULL_TREE; + is_inline = false; is_goto = false; for (bool done = false; !done; ) switch (c_parser_peek_token (parser)->keyword) @@ -6340,6 +6342,10 @@ c_parser_asm_statement (c_parser *parser) c_parser_peek_token (parser)->value); c_parser_consume_token (parser); break; + case RID_INLINE: + is_inline = true; + c_parser_consume_token (parser); + break; case RID_GOTO: is_goto = true; c_parser_consume_token (parser); @@ -6423,7 +6429,8 @@ c_parser_asm_statement (c_parser *parser) c_parser_skip_to_end_of_block_or_statement (parser); ret = build_asm_stmt (quals, build_asm_expr (asm_loc, str, outputs, inputs, - clobbers, labels, simple)); + clobbers, labels, simple, + is_inline)); error: parser->lex_untranslated_string = false; diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h index be63fee..2537d3e 100644 --- a/gcc/c/c-tree.h +++ b/gcc/c/c-tree.h @@ -677,7 +677,8 @@ extern tree build_compound_literal (location_t, tree, tree, bool, extern void check_compound_literal_type (location_t, struct c_type_name *); extern tree c_start_case (location_t, location_t, tree, bool); extern void c_finish_case (tree, tree); -extern tree build_asm_expr (location_t, tree, tree, tree, tree, tree, bool); +extern tree build_asm_expr (location_t, tree, tree, tree, tree, tree, bool, + bool); extern tree build_asm_stmt (tree, tree); extern int c_types_compatible_p (tree, tree); extern tree c_begin_compound_stmt (bool); diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c index 9d09b8d..e013100 100644 --- a/gcc/c/c-typeck.c +++ b/gcc/c/c-typeck.c @@ -10064,7 +10064,7 @@ build_asm_stmt (tree cv_qualifier, tree args) are subtly different. We use a ASM_EXPR node to represent this. */ tree build_asm_expr (location_t loc, tree string, tree outputs, tree inputs, - tree clobbers, tree labels, bool simple) + tree clobbers, tree labels, bool simple, bool is_inline) { tree tail; tree args; @@ -10182,6 +10182,7 @@ build_asm_expr (location_t loc, tree string, tree outputs, tree inputs, as volatile. */ ASM_INPUT_P (args) = simple; ASM_VOLATILE_P (args) = (noutputs == 0); + ASM_INLINE_P (args) = is_inline; return args; } diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 26ded3a..0bd5858 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -6935,7 +6935,7 @@ extern tree begin_compound_stmt (unsigned int); extern void finish_compound_stmt (tree); extern tree finish_asm_stmt (int, tree, tree, tree, tree, - tree); + tree, bool); extern tree finish_label_stmt (tree); extern void finish_label_decl (tree); extern cp_expr finish_parenthesized_expr (cp_expr); diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index d44fd4d..d5174f7 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -19198,6 +19198,7 @@ cp_parser_using_directive (cp_parser* parser) asm-qualifier: volatile + inline goto asm-qualifier-list: @@ -19238,6 +19239,7 @@ cp_parser_asm_definition (cp_parser* parser) bool extended_p = false; bool invalid_inputs_p = false; bool invalid_outputs_p = false; + bool inline_p = false; bool goto_p = false; required_token missing = RT_NONE; @@ -19267,6 +19269,17 @@ cp_parser_asm_definition (cp_parser* parser) else done = true; break; + case RID_INLINE: + if (!inline_p && parser->in_function_body) + { + /* Remember that we saw the `inline' keyword. */ + inline_p = true; + /* Consume the token. */ + cp_lexer_consume_token (parser->lexer); + } + else + done = true; + break; case RID_GOTO: if (!goto_p && parser->in_function_body) { @@ -19408,7 +19421,7 @@ cp_parser_asm_definition (cp_parser* parser) if (parser->in_function_body) { asm_stmt = finish_asm_stmt (volatile_p, string, outputs, - inputs, clobbers, labels); + inputs, clobbers, labels, inline_p); /* If the extended syntax was not used, mark the ASM_EXPR. */ if (!extended_p) { diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index f290cb3..4cd501b 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -17008,7 +17008,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl, tree labels = tsubst_copy_asm_operands (ASM_LABELS (t), args, complain, in_decl); tmp = finish_asm_stmt (ASM_VOLATILE_P (t), string, outputs, inputs, - clobbers, labels); + clobbers, labels, ASM_INLINE_P (t)); tree asm_expr = tmp; if (TREE_CODE (asm_expr) == CLEANUP_POINT_EXPR) asm_expr = TREE_OPERAND (asm_expr, 0); diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c index c7f53d1..fa792bd 100644 --- a/gcc/cp/semantics.c +++ b/gcc/cp/semantics.c @@ -1485,7 +1485,7 @@ finish_compound_stmt (tree stmt) tree finish_asm_stmt (int volatile_p, tree string, tree output_operands, - tree input_operands, tree clobbers, tree labels) + tree input_operands, tree clobbers, tree labels, bool inline_p) { tree r; tree t; @@ -1639,6 +1639,7 @@ finish_asm_stmt (int volatile_p, tree string, tree output_operands, output_operands, input_operands, clobbers, labels); ASM_VOLATILE_P (r) = volatile_p || noutputs == 0; + ASM_INLINE_P (r) = inline_p; r = maybe_cleanup_point_expr_void (r); return add_stmt (r); } diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 7aeb4fd..9e042e3 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -8220,6 +8220,9 @@ The extended form is preferred for mixing C and assembly language within a function, but to include assembly language at top level you must use basic @code{asm}. +You can use @code{asm inline} instead of @code{asm} to have the assembler +code counted as mimimum size for inlining purposes; @pxref{Size of an asm}. + You can also use the @code{asm} keyword to override the assembler name for a C symbol, or to place a C variable in a specific register. @@ -9853,7 +9856,7 @@ does this by counting the number of instructions in the pattern of the @code{asm} and multiplying that by the length of the longest instruction supported by that processor. (When working out the number of instructions, it assumes that any occurrence of a newline or of -whatever statement separator character is supported by the assembler -- +whatever statement separator character is supported by the assembler --- typically @samp{;} --- indicates the end of an instruction.) Normally, GCC's estimate is adequate to ensure that correct @@ -9864,6 +9867,11 @@ space in the object file than is needed for a single instruction. If this happens then the assembler may produce a diagnostic saying that a label is unreachable. +@cindex @code{asm inline} +This size is also used for inlining decisions. If you use @code{asm inline} +instead of just @code{asm}, then for inlining purposes the size of the asm +is taken as the minimum size. + @node Alternate Keywords @section Alternate Keywords @cindex alternate keywords diff --git a/gcc/gimple-pretty-print.c b/gcc/gimple-pretty-print.c index 7dfec91..5b36ef2 100644 --- a/gcc/gimple-pretty-print.c +++ b/gcc/gimple-pretty-print.c @@ -2019,6 +2019,8 @@ dump_gimple_asm (pretty_printer *buffer, gasm *gs, int spc, dump_flags_t flags) pp_string (buffer, "__asm__"); if (gimple_asm_volatile_p (gs)) pp_string (buffer, " __volatile__"); + if (gimple_asm_inline_p (gs)) + pp_string (buffer, " __inline__"); if (gimple_asm_nlabels (gs)) pp_string (buffer, " goto"); pp_string (buffer, "(\""); diff --git a/gcc/gimple.h b/gcc/gimple.h index a5dda93..8a58e07 100644 --- a/gcc/gimple.h +++ b/gcc/gimple.h @@ -137,6 +137,7 @@ enum gimple_rhs_class enum gf_mask { GF_ASM_INPUT = 1 << 0, GF_ASM_VOLATILE = 1 << 1, + GF_ASM_INLINE = 1 << 2, GF_CALL_FROM_THUNK = 1 << 0, GF_CALL_RETURN_SLOT_OPT = 1 << 1, GF_CALL_TAILCALL = 1 << 2, @@ -3911,7 +3912,7 @@ gimple_asm_volatile_p (const gasm *asm_stmt) } -/* If VOLATLE_P is true, mark asm statement ASM_STMT as volatile. */ +/* If VOLATILE_P is true, mark asm statement ASM_STMT as volatile. */ static inline void gimple_asm_set_volatile (gasm *asm_stmt, bool volatile_p) @@ -3923,6 +3924,27 @@ gimple_asm_set_volatile (gasm *asm_stmt, bool volatile_p) } +/* Return true ASM_STMT ASM_STMT is an asm statement marked inline. */ + +static inline bool +gimple_asm_inline_p (const gasm *asm_stmt) +{ + return (asm_stmt->subcode & GF_ASM_INLINE) != 0; +} + + +/* If INLINE_P is true, mark asm statement ASM_STMT as inline. */ + +static inline void +gimple_asm_set_inline (gasm *asm_stmt, bool inline_p) +{ + if (inline_p) + asm_stmt->subcode |= GF_ASM_INLINE; + else + asm_stmt->subcode &= ~GF_ASM_INLINE; +} + + /* If INPUT_P is true, mark asm ASM_STMT as an ASM_INPUT. */ static inline void diff --git a/gcc/gimplify.c b/gcc/gimplify.c index 509fc2f..10b80f2 100644 --- a/gcc/gimplify.c +++ b/gcc/gimplify.c @@ -6315,6 +6315,7 @@ gimplify_asm_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p) gimple_asm_set_volatile (stmt, ASM_VOLATILE_P (expr) || noutputs == 0); gimple_asm_set_input (stmt, ASM_INPUT_P (expr)); + gimple_asm_set_inline (stmt, ASM_INLINE_P (expr)); gimplify_seq_add_stmt (pre_p, stmt); } diff --git a/gcc/ipa-icf-gimple.c b/gcc/ipa-icf-gimple.c index ba39ea3..5361139 100644 --- a/gcc/ipa-icf-gimple.c +++ b/gcc/ipa-icf-gimple.c @@ -993,6 +993,9 @@ func_checker::compare_gimple_asm (const gasm *g1, const gasm *g2) if (gimple_asm_input_p (g1) != gimple_asm_input_p (g2)) return false; + if (gimple_asm_inline_p (g1) != gimple_asm_inline_p (g2)) + return false; + if (gimple_asm_ninputs (g1) != gimple_asm_ninputs (g2)) return false; diff --git a/gcc/testsuite/c-c++-common/torture/asm-inline.c b/gcc/testsuite/c-c++-common/torture/asm-inline.c new file mode 100644 index 0000000..dea8965 --- /dev/null +++ b/gcc/testsuite/c-c++-common/torture/asm-inline.c @@ -0,0 +1,53 @@ +/* { dg-do compile } */ +/* -O0 does no inlining, and -O3 does it too aggressively for this test: */ +/* { dg-skip-if "" { *-*-* } { "-O0" "-O3" } { "" } } +/* The normal asm is not inlined: */ +/* { dg-final { scan-assembler-times "w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w" 2 } } */ +/* But the asm inline is inlined: */ +/* { dg-final { scan-assembler-times "x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x" 8 } } */ + +static void f(void) +{ + asm ("w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\n" + "w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw"); +} + +int f0(void) { f(); return 0; } +int f1(void) { f(); return 1; } +int f2(void) { f(); return 2; } +int f3(void) { f(); return 3; } + +static void fg(void) +{ + asm goto("w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\n" + "w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw" :::: q); + q: ; +} + +int fg0(void) { fg(); return 0; } +int fg1(void) { fg(); return 1; } +int fg2(void) { fg(); return 2; } +int fg3(void) { fg(); return 3; } + +static void g(void) +{ + asm inline("x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\n" + "x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx"); +} + +int g0(void) { g(); return 0; } +int g1(void) { g(); return 1; } +int g2(void) { g(); return 2; } +int g3(void) { g(); return 3; } + +static void gg(void) +{ + asm inline goto("x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\n" + "x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx" :::: q); + q: ; +} + +int gg0(void) { gg(); return 0; } +int gg1(void) { gg(); return 1; } +int gg2(void) { gg(); return 2; } +int gg3(void) { gg(); return 3; } diff --git a/gcc/tree-core.h b/gcc/tree-core.h index 7df5c40..a99ca5d 100644 --- a/gcc/tree-core.h +++ b/gcc/tree-core.h @@ -1151,6 +1151,9 @@ struct GTY(()) tree_base { OMP_CLAUSE_LINEAR_VARIABLE_STRIDE in OMP_CLAUSE_LINEAR + ASM_INLINE_P in + ASM_EXPR + side_effects_flag: TREE_SIDE_EFFECTS in diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c index 297fcd7..274a400 100644 --- a/gcc/tree-inline.c +++ b/gcc/tree-inline.c @@ -4108,6 +4108,9 @@ estimate_num_insns (gimple *stmt, eni_weights *weights) with very long asm statements. */ if (count > 1000) count = 1000; + /* If this asm is asm inline, count anything as minimum size. */ + if (gimple_asm_inline_p (as_a <gasm *> (stmt))) + count = !!count; return MAX (1, count); } diff --git a/gcc/tree.h b/gcc/tree.h index 0ef96ba..f5252e5 100644 --- a/gcc/tree.h +++ b/gcc/tree.h @@ -1245,6 +1245,9 @@ extern tree maybe_wrap_with_location (tree, location_t); ASM_OPERAND with no operands. */ #define ASM_INPUT_P(NODE) (ASM_EXPR_CHECK (NODE)->base.static_flag) #define ASM_VOLATILE_P(NODE) (ASM_EXPR_CHECK (NODE)->base.public_flag) +/* Nonzero if we want to consider this asm as minimum length and cost + for inlining decisions. */ +#define ASM_INLINE_P(NODE) (ASM_EXPR_CHECK (NODE)->base.protected_flag) /* COND_EXPR accessors. */ #define COND_EXPR_COND(NODE) (TREE_OPERAND (COND_EXPR_CHECK (NODE), 0)) -- 1.8.3.1 ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/2] asm inline 2018-10-30 18:41 ` [PATCH 2/2] asm inline Segher Boessenkool @ 2018-10-30 18:58 ` Marek Polacek 2018-11-11 21:33 ` Martin Sebor 2018-11-30 13:14 ` Richard Biener 2 siblings, 0 replies; 23+ messages in thread From: Marek Polacek @ 2018-10-30 18:58 UTC (permalink / raw) To: Segher Boessenkool; +Cc: gcc-patches, jakub On Tue, Oct 30, 2018 at 05:30:34PM +0000, Segher Boessenkool wrote: > --- a/gcc/c/c-typeck.c > +++ b/gcc/c/c-typeck.c > @@ -10064,7 +10064,7 @@ build_asm_stmt (tree cv_qualifier, tree args) > are subtly different. We use a ASM_EXPR node to represent this. */ > tree > build_asm_expr (location_t loc, tree string, tree outputs, tree inputs, > - tree clobbers, tree labels, bool simple) > + tree clobbers, tree labels, bool simple, bool is_inline) The new parameter should probably be described in the comment above. Marek ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/2] asm inline 2018-10-30 18:41 ` [PATCH 2/2] asm inline Segher Boessenkool 2018-10-30 18:58 ` Marek Polacek @ 2018-11-11 21:33 ` Martin Sebor 2018-11-11 22:01 ` Segher Boessenkool 2018-11-30 13:14 ` Richard Biener 2 siblings, 1 reply; 23+ messages in thread From: Martin Sebor @ 2018-11-11 21:33 UTC (permalink / raw) To: Segher Boessenkool, gcc-patches; +Cc: jakub On 10/30/2018 11:30 AM, Segher Boessenkool wrote: > The Linux kernel people want a feature that makes GCC pretend some > inline assembler code is tiny (while it would think it is huge), so > that such code will be inlined essentially always instead of > essentially never. > > This patch lets you say "asm inline" instead of just "asm", with the > result that that inline assembler is always counted as minimum cost > for inlining. It implements this for C and C++. Rather than overloading the inline keyword I think it would be more in keeping both with the design of existing features to control inlining in GCC and with the way the languages are evolving to allow the always_inline (and perhaps also noinline) attribute to apply to asm statements. The inline keyword is commonly understood to be just a hint to the compiler. The attributes, on the other hand, are recognized as binding requests to inline (if possible) or avoid inlining, respectively. Martin > > > 2018-10-30 Segher Boessenkool <segher@kernel.crashing.org> > > * doc/extend.texi (Using Assembly Language with C): Document asm inline. > (Size of an asm): Fix typo. Document asm inline. > * gimple-pretty-print.c (dump_gimple_asm): Handle asm inline. > * gimple.h (enum gf_mask): Add GF_ASM_INLINE. > (gimple_asm_set_volatile): Fix typo. > * gimple_asm_inline_p: New. > * gimple_asm_set_inline: New. > * gimplify.c (gimplify_asm_expr): Propagate the asm inline flag from > tree to gimple. > * ipa-icf-gimple.c (func_checker::compare_gimple_asm): Compare the > gimple_asm_inline_p flag, too. > * tree-core.h (tree_base): Document that protected_flag is ASM_INLINE_P > in an ASM_EXPR. > * tree-inline.c (estimate_num_insns): If gimple_asm_inline_p return > a minimum size for an asm. > * tree.h (ASM_INLINE_P): New. > > gcc/c/ > * c-parser.c (c_parser_asm_statement): Detect the inline keyword > after asm. Pass a flag for it to build_asm_expr. > * c-tree.h (build_asm_expr): Update declaration. > * c-typeck.c (build_asm_stmt): Add is_inline parameter. Use it to > set ASM_INLINE_P. > > gcc/cp/ > * cp-tree.h (finish_asm_stmt): Update declaration. > * parser.c (cp_parser_asm_definition): Detect the inline keyword > after asm. Pass a flag for it to finish_asm_stmt. > * pt.c (tsubst_expr): Pass the ASM_INLINE_P flag to finish_asm_stmt. > * semantics.c (finish_asm_stmt): Add inline_p parameter. Use it to > set ASM_INLINE_P. > > gcc/testsuite/ > * c-c++-common/torture/asm-inline.c: New testcase. > > --- > gcc/c/c-parser.c | 15 +++++-- > gcc/c/c-tree.h | 3 +- > gcc/c/c-typeck.c | 3 +- > gcc/cp/cp-tree.h | 2 +- > gcc/cp/parser.c | 15 ++++++- > gcc/cp/pt.c | 2 +- > gcc/cp/semantics.c | 3 +- > gcc/doc/extend.texi | 10 ++++- > gcc/gimple-pretty-print.c | 2 + > gcc/gimple.h | 24 ++++++++++- > gcc/gimplify.c | 1 + > gcc/ipa-icf-gimple.c | 3 ++ > gcc/testsuite/c-c++-common/torture/asm-inline.c | 53 +++++++++++++++++++++++++ > gcc/tree-core.h | 3 ++ > gcc/tree-inline.c | 3 ++ > gcc/tree.h | 3 ++ > 16 files changed, 133 insertions(+), 12 deletions(-) > create mode 100644 gcc/testsuite/c-c++-common/torture/asm-inline.c > > diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c > index ce9921e..b28b712 100644 > --- a/gcc/c/c-parser.c > +++ b/gcc/c/c-parser.c > @@ -6283,11 +6283,12 @@ c_parser_for_statement (c_parser *parser, bool ivdep, unsigned short unroll, > } > > /* Parse an asm statement, a GNU extension. This is a full-blown asm > - statement with inputs, outputs, clobbers, and volatile and goto tag > - allowed. > + statement with inputs, outputs, clobbers, and volatile, inline, and goto > + tags allowed. > > asm-qualifier: > type-qualifier > + inline > goto > > asm-qualifier-list: > @@ -6315,7 +6316,7 @@ static tree > c_parser_asm_statement (c_parser *parser) > { > tree quals, str, outputs, inputs, clobbers, labels, ret; > - bool simple, is_goto; > + bool simple, is_inline, is_goto; > location_t asm_loc = c_parser_peek_token (parser)->location; > int section, nsections; > > @@ -6323,6 +6324,7 @@ c_parser_asm_statement (c_parser *parser) > c_parser_consume_token (parser); > > quals = NULL_TREE; > + is_inline = false; > is_goto = false; > for (bool done = false; !done; ) > switch (c_parser_peek_token (parser)->keyword) > @@ -6340,6 +6342,10 @@ c_parser_asm_statement (c_parser *parser) > c_parser_peek_token (parser)->value); > c_parser_consume_token (parser); > break; > + case RID_INLINE: > + is_inline = true; > + c_parser_consume_token (parser); > + break; > case RID_GOTO: > is_goto = true; > c_parser_consume_token (parser); > @@ -6423,7 +6429,8 @@ c_parser_asm_statement (c_parser *parser) > c_parser_skip_to_end_of_block_or_statement (parser); > > ret = build_asm_stmt (quals, build_asm_expr (asm_loc, str, outputs, inputs, > - clobbers, labels, simple)); > + clobbers, labels, simple, > + is_inline)); > > error: > parser->lex_untranslated_string = false; > diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h > index be63fee..2537d3e 100644 > --- a/gcc/c/c-tree.h > +++ b/gcc/c/c-tree.h > @@ -677,7 +677,8 @@ extern tree build_compound_literal (location_t, tree, tree, bool, > extern void check_compound_literal_type (location_t, struct c_type_name *); > extern tree c_start_case (location_t, location_t, tree, bool); > extern void c_finish_case (tree, tree); > -extern tree build_asm_expr (location_t, tree, tree, tree, tree, tree, bool); > +extern tree build_asm_expr (location_t, tree, tree, tree, tree, tree, bool, > + bool); > extern tree build_asm_stmt (tree, tree); > extern int c_types_compatible_p (tree, tree); > extern tree c_begin_compound_stmt (bool); > diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c > index 9d09b8d..e013100 100644 > --- a/gcc/c/c-typeck.c > +++ b/gcc/c/c-typeck.c > @@ -10064,7 +10064,7 @@ build_asm_stmt (tree cv_qualifier, tree args) > are subtly different. We use a ASM_EXPR node to represent this. */ > tree > build_asm_expr (location_t loc, tree string, tree outputs, tree inputs, > - tree clobbers, tree labels, bool simple) > + tree clobbers, tree labels, bool simple, bool is_inline) > { > tree tail; > tree args; > @@ -10182,6 +10182,7 @@ build_asm_expr (location_t loc, tree string, tree outputs, tree inputs, > as volatile. */ > ASM_INPUT_P (args) = simple; > ASM_VOLATILE_P (args) = (noutputs == 0); > + ASM_INLINE_P (args) = is_inline; > > return args; > } > diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h > index 26ded3a..0bd5858 100644 > --- a/gcc/cp/cp-tree.h > +++ b/gcc/cp/cp-tree.h > @@ -6935,7 +6935,7 @@ extern tree begin_compound_stmt (unsigned int); > > extern void finish_compound_stmt (tree); > extern tree finish_asm_stmt (int, tree, tree, tree, tree, > - tree); > + tree, bool); > extern tree finish_label_stmt (tree); > extern void finish_label_decl (tree); > extern cp_expr finish_parenthesized_expr (cp_expr); > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c > index d44fd4d..d5174f7 100644 > --- a/gcc/cp/parser.c > +++ b/gcc/cp/parser.c > @@ -19198,6 +19198,7 @@ cp_parser_using_directive (cp_parser* parser) > > asm-qualifier: > volatile > + inline > goto > > asm-qualifier-list: > @@ -19238,6 +19239,7 @@ cp_parser_asm_definition (cp_parser* parser) > bool extended_p = false; > bool invalid_inputs_p = false; > bool invalid_outputs_p = false; > + bool inline_p = false; > bool goto_p = false; > required_token missing = RT_NONE; > > @@ -19267,6 +19269,17 @@ cp_parser_asm_definition (cp_parser* parser) > else > done = true; > break; > + case RID_INLINE: > + if (!inline_p && parser->in_function_body) > + { > + /* Remember that we saw the `inline' keyword. */ > + inline_p = true; > + /* Consume the token. */ > + cp_lexer_consume_token (parser->lexer); > + } > + else > + done = true; > + break; > case RID_GOTO: > if (!goto_p && parser->in_function_body) > { > @@ -19408,7 +19421,7 @@ cp_parser_asm_definition (cp_parser* parser) > if (parser->in_function_body) > { > asm_stmt = finish_asm_stmt (volatile_p, string, outputs, > - inputs, clobbers, labels); > + inputs, clobbers, labels, inline_p); > /* If the extended syntax was not used, mark the ASM_EXPR. */ > if (!extended_p) > { > diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c > index f290cb3..4cd501b 100644 > --- a/gcc/cp/pt.c > +++ b/gcc/cp/pt.c > @@ -17008,7 +17008,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl, > tree labels = tsubst_copy_asm_operands (ASM_LABELS (t), args, > complain, in_decl); > tmp = finish_asm_stmt (ASM_VOLATILE_P (t), string, outputs, inputs, > - clobbers, labels); > + clobbers, labels, ASM_INLINE_P (t)); > tree asm_expr = tmp; > if (TREE_CODE (asm_expr) == CLEANUP_POINT_EXPR) > asm_expr = TREE_OPERAND (asm_expr, 0); > diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c > index c7f53d1..fa792bd 100644 > --- a/gcc/cp/semantics.c > +++ b/gcc/cp/semantics.c > @@ -1485,7 +1485,7 @@ finish_compound_stmt (tree stmt) > > tree > finish_asm_stmt (int volatile_p, tree string, tree output_operands, > - tree input_operands, tree clobbers, tree labels) > + tree input_operands, tree clobbers, tree labels, bool inline_p) > { > tree r; > tree t; > @@ -1639,6 +1639,7 @@ finish_asm_stmt (int volatile_p, tree string, tree output_operands, > output_operands, input_operands, > clobbers, labels); > ASM_VOLATILE_P (r) = volatile_p || noutputs == 0; > + ASM_INLINE_P (r) = inline_p; > r = maybe_cleanup_point_expr_void (r); > return add_stmt (r); > } > diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi > index 7aeb4fd..9e042e3 100644 > --- a/gcc/doc/extend.texi > +++ b/gcc/doc/extend.texi > @@ -8220,6 +8220,9 @@ The extended form is preferred for mixing C and assembly language > within a function, but to include assembly language at > top level you must use basic @code{asm}. > > +You can use @code{asm inline} instead of @code{asm} to have the assembler > +code counted as mimimum size for inlining purposes; @pxref{Size of an asm}. > + > You can also use the @code{asm} keyword to override the assembler name > for a C symbol, or to place a C variable in a specific register. > > @@ -9853,7 +9856,7 @@ does this by counting the number of instructions in the pattern of the > @code{asm} and multiplying that by the length of the longest > instruction supported by that processor. (When working out the number > of instructions, it assumes that any occurrence of a newline or of > -whatever statement separator character is supported by the assembler -- > +whatever statement separator character is supported by the assembler --- > typically @samp{;} --- indicates the end of an instruction.) > > Normally, GCC's estimate is adequate to ensure that correct > @@ -9864,6 +9867,11 @@ space in the object file than is needed for a single instruction. > If this happens then the assembler may produce a diagnostic saying that > a label is unreachable. > > +@cindex @code{asm inline} > +This size is also used for inlining decisions. If you use @code{asm inline} > +instead of just @code{asm}, then for inlining purposes the size of the asm > +is taken as the minimum size. > + > @node Alternate Keywords > @section Alternate Keywords > @cindex alternate keywords > diff --git a/gcc/gimple-pretty-print.c b/gcc/gimple-pretty-print.c > index 7dfec91..5b36ef2 100644 > --- a/gcc/gimple-pretty-print.c > +++ b/gcc/gimple-pretty-print.c > @@ -2019,6 +2019,8 @@ dump_gimple_asm (pretty_printer *buffer, gasm *gs, int spc, dump_flags_t flags) > pp_string (buffer, "__asm__"); > if (gimple_asm_volatile_p (gs)) > pp_string (buffer, " __volatile__"); > + if (gimple_asm_inline_p (gs)) > + pp_string (buffer, " __inline__"); > if (gimple_asm_nlabels (gs)) > pp_string (buffer, " goto"); > pp_string (buffer, "(\""); > diff --git a/gcc/gimple.h b/gcc/gimple.h > index a5dda93..8a58e07 100644 > --- a/gcc/gimple.h > +++ b/gcc/gimple.h > @@ -137,6 +137,7 @@ enum gimple_rhs_class > enum gf_mask { > GF_ASM_INPUT = 1 << 0, > GF_ASM_VOLATILE = 1 << 1, > + GF_ASM_INLINE = 1 << 2, > GF_CALL_FROM_THUNK = 1 << 0, > GF_CALL_RETURN_SLOT_OPT = 1 << 1, > GF_CALL_TAILCALL = 1 << 2, > @@ -3911,7 +3912,7 @@ gimple_asm_volatile_p (const gasm *asm_stmt) > } > > > -/* If VOLATLE_P is true, mark asm statement ASM_STMT as volatile. */ > +/* If VOLATILE_P is true, mark asm statement ASM_STMT as volatile. */ > > static inline void > gimple_asm_set_volatile (gasm *asm_stmt, bool volatile_p) > @@ -3923,6 +3924,27 @@ gimple_asm_set_volatile (gasm *asm_stmt, bool volatile_p) > } > > > +/* Return true ASM_STMT ASM_STMT is an asm statement marked inline. */ > + > +static inline bool > +gimple_asm_inline_p (const gasm *asm_stmt) > +{ > + return (asm_stmt->subcode & GF_ASM_INLINE) != 0; > +} > + > + > +/* If INLINE_P is true, mark asm statement ASM_STMT as inline. */ > + > +static inline void > +gimple_asm_set_inline (gasm *asm_stmt, bool inline_p) > +{ > + if (inline_p) > + asm_stmt->subcode |= GF_ASM_INLINE; > + else > + asm_stmt->subcode &= ~GF_ASM_INLINE; > +} > + > + > /* If INPUT_P is true, mark asm ASM_STMT as an ASM_INPUT. */ > > static inline void > diff --git a/gcc/gimplify.c b/gcc/gimplify.c > index 509fc2f..10b80f2 100644 > --- a/gcc/gimplify.c > +++ b/gcc/gimplify.c > @@ -6315,6 +6315,7 @@ gimplify_asm_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p) > > gimple_asm_set_volatile (stmt, ASM_VOLATILE_P (expr) || noutputs == 0); > gimple_asm_set_input (stmt, ASM_INPUT_P (expr)); > + gimple_asm_set_inline (stmt, ASM_INLINE_P (expr)); > > gimplify_seq_add_stmt (pre_p, stmt); > } > diff --git a/gcc/ipa-icf-gimple.c b/gcc/ipa-icf-gimple.c > index ba39ea3..5361139 100644 > --- a/gcc/ipa-icf-gimple.c > +++ b/gcc/ipa-icf-gimple.c > @@ -993,6 +993,9 @@ func_checker::compare_gimple_asm (const gasm *g1, const gasm *g2) > if (gimple_asm_input_p (g1) != gimple_asm_input_p (g2)) > return false; > > + if (gimple_asm_inline_p (g1) != gimple_asm_inline_p (g2)) > + return false; > + > if (gimple_asm_ninputs (g1) != gimple_asm_ninputs (g2)) > return false; > > diff --git a/gcc/testsuite/c-c++-common/torture/asm-inline.c b/gcc/testsuite/c-c++-common/torture/asm-inline.c > new file mode 100644 > index 0000000..dea8965 > --- /dev/null > +++ b/gcc/testsuite/c-c++-common/torture/asm-inline.c > @@ -0,0 +1,53 @@ > +/* { dg-do compile } */ > +/* -O0 does no inlining, and -O3 does it too aggressively for this test: */ > +/* { dg-skip-if "" { *-*-* } { "-O0" "-O3" } { "" } } > +/* The normal asm is not inlined: */ > +/* { dg-final { scan-assembler-times "w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w" 2 } } */ > +/* But the asm inline is inlined: */ > +/* { dg-final { scan-assembler-times "x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x" 8 } } */ > + > +static void f(void) > +{ > + asm ("w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\n" > + "w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw"); > +} > + > +int f0(void) { f(); return 0; } > +int f1(void) { f(); return 1; } > +int f2(void) { f(); return 2; } > +int f3(void) { f(); return 3; } > + > +static void fg(void) > +{ > + asm goto("w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\n" > + "w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw" :::: q); > + q: ; > +} > + > +int fg0(void) { fg(); return 0; } > +int fg1(void) { fg(); return 1; } > +int fg2(void) { fg(); return 2; } > +int fg3(void) { fg(); return 3; } > + > +static void g(void) > +{ > + asm inline("x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\n" > + "x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx"); > +} > + > +int g0(void) { g(); return 0; } > +int g1(void) { g(); return 1; } > +int g2(void) { g(); return 2; } > +int g3(void) { g(); return 3; } > + > +static void gg(void) > +{ > + asm inline goto("x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\n" > + "x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx" :::: q); > + q: ; > +} > + > +int gg0(void) { gg(); return 0; } > +int gg1(void) { gg(); return 1; } > +int gg2(void) { gg(); return 2; } > +int gg3(void) { gg(); return 3; } > diff --git a/gcc/tree-core.h b/gcc/tree-core.h > index 7df5c40..a99ca5d 100644 > --- a/gcc/tree-core.h > +++ b/gcc/tree-core.h > @@ -1151,6 +1151,9 @@ struct GTY(()) tree_base { > OMP_CLAUSE_LINEAR_VARIABLE_STRIDE in > OMP_CLAUSE_LINEAR > > + ASM_INLINE_P in > + ASM_EXPR > + > side_effects_flag: > > TREE_SIDE_EFFECTS in > diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c > index 297fcd7..274a400 100644 > --- a/gcc/tree-inline.c > +++ b/gcc/tree-inline.c > @@ -4108,6 +4108,9 @@ estimate_num_insns (gimple *stmt, eni_weights *weights) > with very long asm statements. */ > if (count > 1000) > count = 1000; > + /* If this asm is asm inline, count anything as minimum size. */ > + if (gimple_asm_inline_p (as_a <gasm *> (stmt))) > + count = !!count; > return MAX (1, count); > } > > diff --git a/gcc/tree.h b/gcc/tree.h > index 0ef96ba..f5252e5 100644 > --- a/gcc/tree.h > +++ b/gcc/tree.h > @@ -1245,6 +1245,9 @@ extern tree maybe_wrap_with_location (tree, location_t); > ASM_OPERAND with no operands. */ > #define ASM_INPUT_P(NODE) (ASM_EXPR_CHECK (NODE)->base.static_flag) > #define ASM_VOLATILE_P(NODE) (ASM_EXPR_CHECK (NODE)->base.public_flag) > +/* Nonzero if we want to consider this asm as minimum length and cost > + for inlining decisions. */ > +#define ASM_INLINE_P(NODE) (ASM_EXPR_CHECK (NODE)->base.protected_flag) > > /* COND_EXPR accessors. */ > #define COND_EXPR_COND(NODE) (TREE_OPERAND (COND_EXPR_CHECK (NODE), 0)) > ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/2] asm inline 2018-11-11 21:33 ` Martin Sebor @ 2018-11-11 22:01 ` Segher Boessenkool 2018-11-11 23:41 ` Martin Sebor 0 siblings, 1 reply; 23+ messages in thread From: Segher Boessenkool @ 2018-11-11 22:01 UTC (permalink / raw) To: Martin Sebor; +Cc: gcc-patches, jakub On Sun, Nov 11, 2018 at 02:33:34PM -0700, Martin Sebor wrote: > On 10/30/2018 11:30 AM, Segher Boessenkool wrote: > >The Linux kernel people want a feature that makes GCC pretend some > >inline assembler code is tiny (while it would think it is huge), so > >that such code will be inlined essentially always instead of > >essentially never. > > > >This patch lets you say "asm inline" instead of just "asm", with the > >result that that inline assembler is always counted as minimum cost > >for inlining. It implements this for C and C++. > > Rather than overloading the inline keyword I think it would be > more in keeping both with the design of existing features to > control inlining in GCC and with the way the languages are > evolving to allow the always_inline (and perhaps also noinline) > attribute to apply to asm statements. We already "overloaded" the volatile and goto keywords here (it's not overloading, the contexts are completely disjoint). always_inline is a function attribute, and you want to make it a statement attribute (which we do not currently support except for empty statements!) as well. > The inline keyword is commonly understood to be just a hint to > the compiler. That is exactly what it is here. It hints the compiler that this asm is cheap, whatever it may look like. > The attributes, on the other hand, are recognized > as binding requests to inline (if possible) or avoid inlining, > respectively. And that is not what this does (that would be hard to do, in fact). > >+You can use @code{asm inline} instead of @code{asm} to have the assembler > >+code counted as mimimum size for inlining purposes; @pxref{Size of an > >asm}. Segher ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/2] asm inline 2018-11-11 22:01 ` Segher Boessenkool @ 2018-11-11 23:41 ` Martin Sebor 2018-11-12 0:19 ` Segher Boessenkool 0 siblings, 1 reply; 23+ messages in thread From: Martin Sebor @ 2018-11-11 23:41 UTC (permalink / raw) To: Segher Boessenkool; +Cc: gcc-patches, jakub On 11/11/2018 03:00 PM, Segher Boessenkool wrote: > On Sun, Nov 11, 2018 at 02:33:34PM -0700, Martin Sebor wrote: >> On 10/30/2018 11:30 AM, Segher Boessenkool wrote: >>> The Linux kernel people want a feature that makes GCC pretend some >>> inline assembler code is tiny (while it would think it is huge), so >>> that such code will be inlined essentially always instead of >>> essentially never. >>> >>> This patch lets you say "asm inline" instead of just "asm", with the >>> result that that inline assembler is always counted as minimum cost >>> for inlining. It implements this for C and C++. >> >> Rather than overloading the inline keyword I think it would be >> more in keeping both with the design of existing features to >> control inlining in GCC and with the way the languages are >> evolving to allow the always_inline (and perhaps also noinline) >> attribute to apply to asm statements. > > We already "overloaded" the volatile and goto keywords here (it's not > overloading, the contexts are completely disjoint). > > always_inline is a function attribute, and you want to make it a statement > attribute (which we do not currently support except for empty statements!) > as well. Yes, I suggest using a statement attribute for this. I believe it would be more appropriate that overloading the meaning of an existing keyword in this context. C++ is entertaining proposals to introduce a few statement attributes (e.g., likely/unlikely and even unreachable) so as I said, adding one to GCC would be in like with the direction the languages are moving (C has adopted the C++ 11 attributes for C2X and it likely will continue to do so going forward). Supporting an attribute in this context also has a lower cost for third party tools that parse code (and are already prepared to deal with attributes). Adding a new keyword here has a good chance of breaking some of those tools. >> The inline keyword is commonly understood to be just a hint to >> the compiler. > > That is exactly what it is here. It hints the compiler that this asm > is cheap, whatever it may look like. The way you described the purpose of asm inline: "such code will be inlined essentially always instead of essentially never" sounded to me like it's close to the effect of attribute always_inline. But after reading the patch it looks like the asm just overrides the number of instructions GCC estimates the statement expands into. If I read the code right then a different attribute altogether would seem more appropriate (e.g., perhaps even something like insn_count (N); that would make it possible to provide an exact instruction count and also prevent the inlining of the enclosing function by specifying a very large count). In any event, overloading the inline keyword for this purpose doesn't seem like a good approach to me. Martin ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/2] asm inline 2018-11-11 23:41 ` Martin Sebor @ 2018-11-12 0:19 ` Segher Boessenkool 0 siblings, 0 replies; 23+ messages in thread From: Segher Boessenkool @ 2018-11-12 0:19 UTC (permalink / raw) To: Martin Sebor; +Cc: gcc-patches, jakub On Sun, Nov 11, 2018 at 04:41:19PM -0700, Martin Sebor wrote: > On 11/11/2018 03:00 PM, Segher Boessenkool wrote: > >On Sun, Nov 11, 2018 at 02:33:34PM -0700, Martin Sebor wrote: > >>On 10/30/2018 11:30 AM, Segher Boessenkool wrote: > >>>The Linux kernel people want a feature that makes GCC pretend some > >>>inline assembler code is tiny (while it would think it is huge), so > >>>that such code will be inlined essentially always instead of > >>>essentially never. > >>> > >>>This patch lets you say "asm inline" instead of just "asm", with the > >>>result that that inline assembler is always counted as minimum cost > >>>for inlining. It implements this for C and C++. > >> > >>Rather than overloading the inline keyword I think it would be > >>more in keeping both with the design of existing features to > >>control inlining in GCC and with the way the languages are > >>evolving to allow the always_inline (and perhaps also noinline) > >>attribute to apply to asm statements. > > > >We already "overloaded" the volatile and goto keywords here (it's not > >overloading, the contexts are completely disjoint). > > > >always_inline is a function attribute, and you want to make it a statement > >attribute (which we do not currently support except for empty statements!) > >as well. > > Yes, I suggest using a statement attribute for this. I believe > it would be more appropriate that overloading the meaning of > an existing keyword in this context. It is *not* overloading the meaning in this context. There *was* no meaning in this context. Also, all of the other keywords allowed here (const, volatile, restrict, goto) have different meanings in other contexts already. > C++ is entertaining proposals to introduce a few statement > attributes (e.g., likely/unlikely and even unreachable) so > as I said, adding one to GCC would be in like with > the direction the languages are moving (C has adopted the C++ > 11 attributes for C2X and it likely will continue to do so going > forward). As I've said many times now, I think attributes are a bad match for this. Also, I am not going to implement statement attributes just for this. > Supporting an attribute in this context also has a lower cost > for third party tools that parse code (and are already prepared > to deal with attributes). Adding a new keyword here has a good > chance of breaking some of those tools. I don't see why I would care. Sorry. Extended asm is a GCC extension, so we make the rules. The first patch makes any order and combination of qualifiers (and goto and inline) valid for asm, where before only zero or one qualifiers and zero or one goto were allowed (in that order). This gives exactly the same problem for 3rd party tools, but it is an obvious improvement (and even a bugfix). > >>The inline keyword is commonly understood to be just a hint to > >>the compiler. > > > >That is exactly what it is here. It hints the compiler that this asm > >is cheap, whatever it may look like. > > The way you described the purpose of asm inline: "such code will > be inlined essentially always instead of essentially never" > sounded to me like it's close to the effect of attribute > always_inline. But after reading the patch it looks like the asm > just overrides the number of instructions GCC estimates > the statement expands into. Only for the inlining decisions. It still uses the conservative estimate for things like the length attribute (the machine description thing), and other things required for correctness. > If I read the code right then > a different attribute altogether would seem more appropriate > (e.g., perhaps even something like insn_count (N); that would > make it possible to provide an exact instruction count and also > prevent the inlining of the enclosing function by specifying > a very large count). No, the user does not know what units is counted in here. Would there be any real benefit anyway? I don't see it. > In any event, overloading the inline > keyword for this purpose doesn't seem like a good approach > to me. It is not overloading anything. Segher ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/2] asm inline 2018-10-30 18:41 ` [PATCH 2/2] asm inline Segher Boessenkool 2018-10-30 18:58 ` Marek Polacek 2018-11-11 21:33 ` Martin Sebor @ 2018-11-30 13:14 ` Richard Biener 2 siblings, 0 replies; 23+ messages in thread From: Richard Biener @ 2018-11-30 13:14 UTC (permalink / raw) To: Segher Boessenkool; +Cc: GCC Patches, Jakub Jelinek On Tue, Oct 30, 2018 at 6:31 PM Segher Boessenkool <segher@kernel.crashing.org> wrote: > > The Linux kernel people want a feature that makes GCC pretend some > inline assembler code is tiny (while it would think it is huge), so > that such code will be inlined essentially always instead of > essentially never. > > This patch lets you say "asm inline" instead of just "asm", with the > result that that inline assembler is always counted as minimum cost > for inlining. It implements this for C and C++. The middle-end and documentation changes are OK. I suppose the FE changes are as well in case [2/2] is approved. Thanks, Richard. > > 2018-10-30 Segher Boessenkool <segher@kernel.crashing.org> > > * doc/extend.texi (Using Assembly Language with C): Document asm inline. > (Size of an asm): Fix typo. Document asm inline. > * gimple-pretty-print.c (dump_gimple_asm): Handle asm inline. > * gimple.h (enum gf_mask): Add GF_ASM_INLINE. > (gimple_asm_set_volatile): Fix typo. > * gimple_asm_inline_p: New. > * gimple_asm_set_inline: New. > * gimplify.c (gimplify_asm_expr): Propagate the asm inline flag from > tree to gimple. > * ipa-icf-gimple.c (func_checker::compare_gimple_asm): Compare the > gimple_asm_inline_p flag, too. > * tree-core.h (tree_base): Document that protected_flag is ASM_INLINE_P > in an ASM_EXPR. > * tree-inline.c (estimate_num_insns): If gimple_asm_inline_p return > a minimum size for an asm. > * tree.h (ASM_INLINE_P): New. > > gcc/c/ > * c-parser.c (c_parser_asm_statement): Detect the inline keyword > after asm. Pass a flag for it to build_asm_expr. > * c-tree.h (build_asm_expr): Update declaration. > * c-typeck.c (build_asm_stmt): Add is_inline parameter. Use it to > set ASM_INLINE_P. > > gcc/cp/ > * cp-tree.h (finish_asm_stmt): Update declaration. > * parser.c (cp_parser_asm_definition): Detect the inline keyword > after asm. Pass a flag for it to finish_asm_stmt. > * pt.c (tsubst_expr): Pass the ASM_INLINE_P flag to finish_asm_stmt. > * semantics.c (finish_asm_stmt): Add inline_p parameter. Use it to > set ASM_INLINE_P. > > gcc/testsuite/ > * c-c++-common/torture/asm-inline.c: New testcase. > > --- > gcc/c/c-parser.c | 15 +++++-- > gcc/c/c-tree.h | 3 +- > gcc/c/c-typeck.c | 3 +- > gcc/cp/cp-tree.h | 2 +- > gcc/cp/parser.c | 15 ++++++- > gcc/cp/pt.c | 2 +- > gcc/cp/semantics.c | 3 +- > gcc/doc/extend.texi | 10 ++++- > gcc/gimple-pretty-print.c | 2 + > gcc/gimple.h | 24 ++++++++++- > gcc/gimplify.c | 1 + > gcc/ipa-icf-gimple.c | 3 ++ > gcc/testsuite/c-c++-common/torture/asm-inline.c | 53 +++++++++++++++++++++++++ > gcc/tree-core.h | 3 ++ > gcc/tree-inline.c | 3 ++ > gcc/tree.h | 3 ++ > 16 files changed, 133 insertions(+), 12 deletions(-) > create mode 100644 gcc/testsuite/c-c++-common/torture/asm-inline.c > > diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c > index ce9921e..b28b712 100644 > --- a/gcc/c/c-parser.c > +++ b/gcc/c/c-parser.c > @@ -6283,11 +6283,12 @@ c_parser_for_statement (c_parser *parser, bool ivdep, unsigned short unroll, > } > > /* Parse an asm statement, a GNU extension. This is a full-blown asm > - statement with inputs, outputs, clobbers, and volatile and goto tag > - allowed. > + statement with inputs, outputs, clobbers, and volatile, inline, and goto > + tags allowed. > > asm-qualifier: > type-qualifier > + inline > goto > > asm-qualifier-list: > @@ -6315,7 +6316,7 @@ static tree > c_parser_asm_statement (c_parser *parser) > { > tree quals, str, outputs, inputs, clobbers, labels, ret; > - bool simple, is_goto; > + bool simple, is_inline, is_goto; > location_t asm_loc = c_parser_peek_token (parser)->location; > int section, nsections; > > @@ -6323,6 +6324,7 @@ c_parser_asm_statement (c_parser *parser) > c_parser_consume_token (parser); > > quals = NULL_TREE; > + is_inline = false; > is_goto = false; > for (bool done = false; !done; ) > switch (c_parser_peek_token (parser)->keyword) > @@ -6340,6 +6342,10 @@ c_parser_asm_statement (c_parser *parser) > c_parser_peek_token (parser)->value); > c_parser_consume_token (parser); > break; > + case RID_INLINE: > + is_inline = true; > + c_parser_consume_token (parser); > + break; > case RID_GOTO: > is_goto = true; > c_parser_consume_token (parser); > @@ -6423,7 +6429,8 @@ c_parser_asm_statement (c_parser *parser) > c_parser_skip_to_end_of_block_or_statement (parser); > > ret = build_asm_stmt (quals, build_asm_expr (asm_loc, str, outputs, inputs, > - clobbers, labels, simple)); > + clobbers, labels, simple, > + is_inline)); > > error: > parser->lex_untranslated_string = false; > diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h > index be63fee..2537d3e 100644 > --- a/gcc/c/c-tree.h > +++ b/gcc/c/c-tree.h > @@ -677,7 +677,8 @@ extern tree build_compound_literal (location_t, tree, tree, bool, > extern void check_compound_literal_type (location_t, struct c_type_name *); > extern tree c_start_case (location_t, location_t, tree, bool); > extern void c_finish_case (tree, tree); > -extern tree build_asm_expr (location_t, tree, tree, tree, tree, tree, bool); > +extern tree build_asm_expr (location_t, tree, tree, tree, tree, tree, bool, > + bool); > extern tree build_asm_stmt (tree, tree); > extern int c_types_compatible_p (tree, tree); > extern tree c_begin_compound_stmt (bool); > diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c > index 9d09b8d..e013100 100644 > --- a/gcc/c/c-typeck.c > +++ b/gcc/c/c-typeck.c > @@ -10064,7 +10064,7 @@ build_asm_stmt (tree cv_qualifier, tree args) > are subtly different. We use a ASM_EXPR node to represent this. */ > tree > build_asm_expr (location_t loc, tree string, tree outputs, tree inputs, > - tree clobbers, tree labels, bool simple) > + tree clobbers, tree labels, bool simple, bool is_inline) > { > tree tail; > tree args; > @@ -10182,6 +10182,7 @@ build_asm_expr (location_t loc, tree string, tree outputs, tree inputs, > as volatile. */ > ASM_INPUT_P (args) = simple; > ASM_VOLATILE_P (args) = (noutputs == 0); > + ASM_INLINE_P (args) = is_inline; > > return args; > } > diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h > index 26ded3a..0bd5858 100644 > --- a/gcc/cp/cp-tree.h > +++ b/gcc/cp/cp-tree.h > @@ -6935,7 +6935,7 @@ extern tree begin_compound_stmt (unsigned int); > > extern void finish_compound_stmt (tree); > extern tree finish_asm_stmt (int, tree, tree, tree, tree, > - tree); > + tree, bool); > extern tree finish_label_stmt (tree); > extern void finish_label_decl (tree); > extern cp_expr finish_parenthesized_expr (cp_expr); > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c > index d44fd4d..d5174f7 100644 > --- a/gcc/cp/parser.c > +++ b/gcc/cp/parser.c > @@ -19198,6 +19198,7 @@ cp_parser_using_directive (cp_parser* parser) > > asm-qualifier: > volatile > + inline > goto > > asm-qualifier-list: > @@ -19238,6 +19239,7 @@ cp_parser_asm_definition (cp_parser* parser) > bool extended_p = false; > bool invalid_inputs_p = false; > bool invalid_outputs_p = false; > + bool inline_p = false; > bool goto_p = false; > required_token missing = RT_NONE; > > @@ -19267,6 +19269,17 @@ cp_parser_asm_definition (cp_parser* parser) > else > done = true; > break; > + case RID_INLINE: > + if (!inline_p && parser->in_function_body) > + { > + /* Remember that we saw the `inline' keyword. */ > + inline_p = true; > + /* Consume the token. */ > + cp_lexer_consume_token (parser->lexer); > + } > + else > + done = true; > + break; > case RID_GOTO: > if (!goto_p && parser->in_function_body) > { > @@ -19408,7 +19421,7 @@ cp_parser_asm_definition (cp_parser* parser) > if (parser->in_function_body) > { > asm_stmt = finish_asm_stmt (volatile_p, string, outputs, > - inputs, clobbers, labels); > + inputs, clobbers, labels, inline_p); > /* If the extended syntax was not used, mark the ASM_EXPR. */ > if (!extended_p) > { > diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c > index f290cb3..4cd501b 100644 > --- a/gcc/cp/pt.c > +++ b/gcc/cp/pt.c > @@ -17008,7 +17008,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl, > tree labels = tsubst_copy_asm_operands (ASM_LABELS (t), args, > complain, in_decl); > tmp = finish_asm_stmt (ASM_VOLATILE_P (t), string, outputs, inputs, > - clobbers, labels); > + clobbers, labels, ASM_INLINE_P (t)); > tree asm_expr = tmp; > if (TREE_CODE (asm_expr) == CLEANUP_POINT_EXPR) > asm_expr = TREE_OPERAND (asm_expr, 0); > diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c > index c7f53d1..fa792bd 100644 > --- a/gcc/cp/semantics.c > +++ b/gcc/cp/semantics.c > @@ -1485,7 +1485,7 @@ finish_compound_stmt (tree stmt) > > tree > finish_asm_stmt (int volatile_p, tree string, tree output_operands, > - tree input_operands, tree clobbers, tree labels) > + tree input_operands, tree clobbers, tree labels, bool inline_p) > { > tree r; > tree t; > @@ -1639,6 +1639,7 @@ finish_asm_stmt (int volatile_p, tree string, tree output_operands, > output_operands, input_operands, > clobbers, labels); > ASM_VOLATILE_P (r) = volatile_p || noutputs == 0; > + ASM_INLINE_P (r) = inline_p; > r = maybe_cleanup_point_expr_void (r); > return add_stmt (r); > } > diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi > index 7aeb4fd..9e042e3 100644 > --- a/gcc/doc/extend.texi > +++ b/gcc/doc/extend.texi > @@ -8220,6 +8220,9 @@ The extended form is preferred for mixing C and assembly language > within a function, but to include assembly language at > top level you must use basic @code{asm}. > > +You can use @code{asm inline} instead of @code{asm} to have the assembler > +code counted as mimimum size for inlining purposes; @pxref{Size of an asm}. > + > You can also use the @code{asm} keyword to override the assembler name > for a C symbol, or to place a C variable in a specific register. > > @@ -9853,7 +9856,7 @@ does this by counting the number of instructions in the pattern of the > @code{asm} and multiplying that by the length of the longest > instruction supported by that processor. (When working out the number > of instructions, it assumes that any occurrence of a newline or of > -whatever statement separator character is supported by the assembler -- > +whatever statement separator character is supported by the assembler --- > typically @samp{;} --- indicates the end of an instruction.) > > Normally, GCC's estimate is adequate to ensure that correct > @@ -9864,6 +9867,11 @@ space in the object file than is needed for a single instruction. > If this happens then the assembler may produce a diagnostic saying that > a label is unreachable. > > +@cindex @code{asm inline} > +This size is also used for inlining decisions. If you use @code{asm inline} > +instead of just @code{asm}, then for inlining purposes the size of the asm > +is taken as the minimum size. > + > @node Alternate Keywords > @section Alternate Keywords > @cindex alternate keywords > diff --git a/gcc/gimple-pretty-print.c b/gcc/gimple-pretty-print.c > index 7dfec91..5b36ef2 100644 > --- a/gcc/gimple-pretty-print.c > +++ b/gcc/gimple-pretty-print.c > @@ -2019,6 +2019,8 @@ dump_gimple_asm (pretty_printer *buffer, gasm *gs, int spc, dump_flags_t flags) > pp_string (buffer, "__asm__"); > if (gimple_asm_volatile_p (gs)) > pp_string (buffer, " __volatile__"); > + if (gimple_asm_inline_p (gs)) > + pp_string (buffer, " __inline__"); > if (gimple_asm_nlabels (gs)) > pp_string (buffer, " goto"); > pp_string (buffer, "(\""); > diff --git a/gcc/gimple.h b/gcc/gimple.h > index a5dda93..8a58e07 100644 > --- a/gcc/gimple.h > +++ b/gcc/gimple.h > @@ -137,6 +137,7 @@ enum gimple_rhs_class > enum gf_mask { > GF_ASM_INPUT = 1 << 0, > GF_ASM_VOLATILE = 1 << 1, > + GF_ASM_INLINE = 1 << 2, > GF_CALL_FROM_THUNK = 1 << 0, > GF_CALL_RETURN_SLOT_OPT = 1 << 1, > GF_CALL_TAILCALL = 1 << 2, > @@ -3911,7 +3912,7 @@ gimple_asm_volatile_p (const gasm *asm_stmt) > } > > > -/* If VOLATLE_P is true, mark asm statement ASM_STMT as volatile. */ > +/* If VOLATILE_P is true, mark asm statement ASM_STMT as volatile. */ > > static inline void > gimple_asm_set_volatile (gasm *asm_stmt, bool volatile_p) > @@ -3923,6 +3924,27 @@ gimple_asm_set_volatile (gasm *asm_stmt, bool volatile_p) > } > > > +/* Return true ASM_STMT ASM_STMT is an asm statement marked inline. */ > + > +static inline bool > +gimple_asm_inline_p (const gasm *asm_stmt) > +{ > + return (asm_stmt->subcode & GF_ASM_INLINE) != 0; > +} > + > + > +/* If INLINE_P is true, mark asm statement ASM_STMT as inline. */ > + > +static inline void > +gimple_asm_set_inline (gasm *asm_stmt, bool inline_p) > +{ > + if (inline_p) > + asm_stmt->subcode |= GF_ASM_INLINE; > + else > + asm_stmt->subcode &= ~GF_ASM_INLINE; > +} > + > + > /* If INPUT_P is true, mark asm ASM_STMT as an ASM_INPUT. */ > > static inline void > diff --git a/gcc/gimplify.c b/gcc/gimplify.c > index 509fc2f..10b80f2 100644 > --- a/gcc/gimplify.c > +++ b/gcc/gimplify.c > @@ -6315,6 +6315,7 @@ gimplify_asm_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p) > > gimple_asm_set_volatile (stmt, ASM_VOLATILE_P (expr) || noutputs == 0); > gimple_asm_set_input (stmt, ASM_INPUT_P (expr)); > + gimple_asm_set_inline (stmt, ASM_INLINE_P (expr)); > > gimplify_seq_add_stmt (pre_p, stmt); > } > diff --git a/gcc/ipa-icf-gimple.c b/gcc/ipa-icf-gimple.c > index ba39ea3..5361139 100644 > --- a/gcc/ipa-icf-gimple.c > +++ b/gcc/ipa-icf-gimple.c > @@ -993,6 +993,9 @@ func_checker::compare_gimple_asm (const gasm *g1, const gasm *g2) > if (gimple_asm_input_p (g1) != gimple_asm_input_p (g2)) > return false; > > + if (gimple_asm_inline_p (g1) != gimple_asm_inline_p (g2)) > + return false; > + > if (gimple_asm_ninputs (g1) != gimple_asm_ninputs (g2)) > return false; > > diff --git a/gcc/testsuite/c-c++-common/torture/asm-inline.c b/gcc/testsuite/c-c++-common/torture/asm-inline.c > new file mode 100644 > index 0000000..dea8965 > --- /dev/null > +++ b/gcc/testsuite/c-c++-common/torture/asm-inline.c > @@ -0,0 +1,53 @@ > +/* { dg-do compile } */ > +/* -O0 does no inlining, and -O3 does it too aggressively for this test: */ > +/* { dg-skip-if "" { *-*-* } { "-O0" "-O3" } { "" } } > +/* The normal asm is not inlined: */ > +/* { dg-final { scan-assembler-times "w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w.w" 2 } } */ > +/* But the asm inline is inlined: */ > +/* { dg-final { scan-assembler-times "x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x.x" 8 } } */ > + > +static void f(void) > +{ > + asm ("w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\n" > + "w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw"); > +} > + > +int f0(void) { f(); return 0; } > +int f1(void) { f(); return 1; } > +int f2(void) { f(); return 2; } > +int f3(void) { f(); return 3; } > + > +static void fg(void) > +{ > + asm goto("w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\n" > + "w\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw\nw" :::: q); > + q: ; > +} > + > +int fg0(void) { fg(); return 0; } > +int fg1(void) { fg(); return 1; } > +int fg2(void) { fg(); return 2; } > +int fg3(void) { fg(); return 3; } > + > +static void g(void) > +{ > + asm inline("x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\n" > + "x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx"); > +} > + > +int g0(void) { g(); return 0; } > +int g1(void) { g(); return 1; } > +int g2(void) { g(); return 2; } > +int g3(void) { g(); return 3; } > + > +static void gg(void) > +{ > + asm inline goto("x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\n" > + "x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx" :::: q); > + q: ; > +} > + > +int gg0(void) { gg(); return 0; } > +int gg1(void) { gg(); return 1; } > +int gg2(void) { gg(); return 2; } > +int gg3(void) { gg(); return 3; } > diff --git a/gcc/tree-core.h b/gcc/tree-core.h > index 7df5c40..a99ca5d 100644 > --- a/gcc/tree-core.h > +++ b/gcc/tree-core.h > @@ -1151,6 +1151,9 @@ struct GTY(()) tree_base { > OMP_CLAUSE_LINEAR_VARIABLE_STRIDE in > OMP_CLAUSE_LINEAR > > + ASM_INLINE_P in > + ASM_EXPR > + > side_effects_flag: > > TREE_SIDE_EFFECTS in > diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c > index 297fcd7..274a400 100644 > --- a/gcc/tree-inline.c > +++ b/gcc/tree-inline.c > @@ -4108,6 +4108,9 @@ estimate_num_insns (gimple *stmt, eni_weights *weights) > with very long asm statements. */ > if (count > 1000) > count = 1000; > + /* If this asm is asm inline, count anything as minimum size. */ > + if (gimple_asm_inline_p (as_a <gasm *> (stmt))) > + count = !!count; > return MAX (1, count); > } > > diff --git a/gcc/tree.h b/gcc/tree.h > index 0ef96ba..f5252e5 100644 > --- a/gcc/tree.h > +++ b/gcc/tree.h > @@ -1245,6 +1245,9 @@ extern tree maybe_wrap_with_location (tree, location_t); > ASM_OPERAND with no operands. */ > #define ASM_INPUT_P(NODE) (ASM_EXPR_CHECK (NODE)->base.static_flag) > #define ASM_VOLATILE_P(NODE) (ASM_EXPR_CHECK (NODE)->base.public_flag) > +/* Nonzero if we want to consider this asm as minimum length and cost > + for inlining decisions. */ > +#define ASM_INLINE_P(NODE) (ASM_EXPR_CHECK (NODE)->base.protected_flag) > > /* COND_EXPR accessors. */ > #define COND_EXPR_COND(NODE) (TREE_OPERAND (COND_EXPR_CHECK (NODE), 0)) > -- > 1.8.3.1 > ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 1/2] asm qualifiers (PR55681) 2018-10-30 18:01 [PATCH 0/2] asm qualifiers (PR55681) and asm input Segher Boessenkool 2018-10-30 18:41 ` [PATCH 2/2] asm inline Segher Boessenkool @ 2018-10-30 18:56 ` Segher Boessenkool 2018-11-29 13:35 ` Segher Boessenkool 2018-11-11 0:33 ` [PATCH 0/2] asm qualifiers (PR55681) and asm input Segher Boessenkool 2 siblings, 1 reply; 23+ messages in thread From: Segher Boessenkool @ 2018-10-30 18:56 UTC (permalink / raw) To: gcc-patches; +Cc: jakub, Segher Boessenkool PR55681 observes that currently only one qualifier is allowed for inline asm, so that e.g. "volatile asm" is allowed, "const asm" is also okay (with a warning), but "const volatile asm" gives an error. Also "const const asm" is an error (while "const const int" is okay for C), "goto" has to be last, and "_Atomic" isn't handled at all. This patch fixes all these. It allows any order of qualifiers (and goto), allows them all for C, allows duplications for C. For C++ it still allows only a single volatile and single goto, but in any order. 2018-10-30 Segher Boessenkool <segher@kernel.crashing.org> gcc/c/ PR inline-asm/55681 * c-parser.c (c_parser_for_statement): Update grammar. Allow any combination of type-qualifiers and goto in any order, with repetitions allowed. gcc/cp/ PR inline-asm/55681 * parser.c (cp_parser_using_directive): Update grammar. Allow any combination of volatile and goto in any order, without repetitions. --- gcc/c/c-parser.c | 66 +++++++++++++++++++++++++++--------------------- gcc/cp/parser.c | 77 +++++++++++++++++++++++++++++++++++++------------------- 2 files changed, 89 insertions(+), 54 deletions(-) diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c index ee66ce8..ce9921e 100644 --- a/gcc/c/c-parser.c +++ b/gcc/c/c-parser.c @@ -6283,23 +6283,31 @@ c_parser_for_statement (c_parser *parser, bool ivdep, unsigned short unroll, } /* Parse an asm statement, a GNU extension. This is a full-blown asm - statement with inputs, outputs, clobbers, and volatile tag + statement with inputs, outputs, clobbers, and volatile and goto tag allowed. + asm-qualifier: + type-qualifier + goto + + asm-qualifier-list: + asm-qualifier-list asm-qualifier + asm-qualifier + asm-statement: - asm type-qualifier[opt] ( asm-argument ) ; - asm type-qualifier[opt] goto ( asm-goto-argument ) ; + asm asm-qualifier-list[opt] ( asm-argument ) ; asm-argument: asm-string-literal asm-string-literal : asm-operands[opt] asm-string-literal : asm-operands[opt] : asm-operands[opt] - asm-string-literal : asm-operands[opt] : asm-operands[opt] : asm-clobbers[opt] - - asm-goto-argument: + asm-string-literal : asm-operands[opt] : asm-operands[opt] \ + : asm-clobbers[opt] asm-string-literal : : asm-operands[opt] : asm-clobbers[opt] \ : asm-goto-operands + The form with asm-goto-operands is valid if and only if the + asm-qualifier-list contains goto, and is the only allowed form in that case. Qualifiers other than volatile are accepted in the syntax but warned for. */ @@ -6313,30 +6321,32 @@ c_parser_asm_statement (c_parser *parser) gcc_assert (c_parser_next_token_is_keyword (parser, RID_ASM)); c_parser_consume_token (parser); - if (c_parser_next_token_is_keyword (parser, RID_VOLATILE)) - { - quals = c_parser_peek_token (parser)->value; - c_parser_consume_token (parser); - } - else if (c_parser_next_token_is_keyword (parser, RID_CONST) - || c_parser_next_token_is_keyword (parser, RID_RESTRICT)) - { - warning_at (c_parser_peek_token (parser)->location, - 0, - "%E qualifier ignored on asm", - c_parser_peek_token (parser)->value); - quals = NULL_TREE; - c_parser_consume_token (parser); - } - else - quals = NULL_TREE; + quals = NULL_TREE; is_goto = false; - if (c_parser_next_token_is_keyword (parser, RID_GOTO)) - { - c_parser_consume_token (parser); - is_goto = true; - } + for (bool done = false; !done; ) + switch (c_parser_peek_token (parser)->keyword) + { + case RID_VOLATILE: + quals = c_parser_peek_token (parser)->value; + c_parser_consume_token (parser); + break; + case RID_CONST: + case RID_RESTRICT: + case RID_ATOMIC: + warning_at (c_parser_peek_token (parser)->location, + 0, + "%E qualifier ignored on asm", + c_parser_peek_token (parser)->value); + c_parser_consume_token (parser); + break; + case RID_GOTO: + is_goto = true; + c_parser_consume_token (parser); + break; + default: + done = true; + } /* ??? Follow the C++ parser rather than using the lex_untranslated_string kludge. */ diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index ebe326e..d44fd4d 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -19196,22 +19196,34 @@ cp_parser_using_directive (cp_parser* parser) /* Parse an asm-definition. + asm-qualifier: + volatile + goto + + asm-qualifier-list: + asm-qualifier + asm-qualifier-list asm-qualifier + asm-definition: asm ( string-literal ) ; GNU Extension: asm-definition: - asm volatile [opt] ( string-literal ) ; - asm volatile [opt] ( string-literal : asm-operand-list [opt] ) ; - asm volatile [opt] ( string-literal : asm-operand-list [opt] - : asm-operand-list [opt] ) ; - asm volatile [opt] ( string-literal : asm-operand-list [opt] - : asm-operand-list [opt] + asm asm-qualifier-list [opt] ( string-literal ) ; + asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt] ) ; + asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt] + : asm-operand-list [opt] ) ; + asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt] + : asm-operand-list [opt] : asm-clobber-list [opt] ) ; - asm volatile [opt] goto ( string-literal : : asm-operand-list [opt] - : asm-clobber-list [opt] - : asm-goto-list ) ; */ + asm asm-qualifier-list [opt] ( string-literal : : asm-operand-list [opt] + : asm-clobber-list [opt] + : asm-goto-list ) ; + + The form with asm-goto-list is valid if and only if the asm-qualifier-list + contains goto, and is the only allowed form in that case. No duplicates are + allowed in an asm-qualifier-list. */ static void cp_parser_asm_definition (cp_parser* parser) @@ -19240,23 +19252,36 @@ cp_parser_asm_definition (cp_parser* parser) } /* See if the next token is `volatile'. */ - if (cp_parser_allow_gnu_extensions_p (parser) - && cp_lexer_next_token_is_keyword (parser->lexer, RID_VOLATILE)) - { - /* Remember that we saw the `volatile' keyword. */ - volatile_p = true; - /* Consume the token. */ - cp_lexer_consume_token (parser->lexer); - } - if (cp_parser_allow_gnu_extensions_p (parser) - && parser->in_function_body - && cp_lexer_next_token_is_keyword (parser->lexer, RID_GOTO)) - { - /* Remember that we saw the `goto' keyword. */ - goto_p = true; - /* Consume the token. */ - cp_lexer_consume_token (parser->lexer); - } + if (cp_parser_allow_gnu_extensions_p (parser)) + for (bool done = false; !done ; ) + switch (cp_lexer_peek_token (parser->lexer)->keyword) + { + case RID_VOLATILE: + if (!volatile_p) + { + /* Remember that we saw the `volatile' keyword. */ + volatile_p = true; + /* Consume the token. */ + cp_lexer_consume_token (parser->lexer); + } + else + done = true; + break; + case RID_GOTO: + if (!goto_p && parser->in_function_body) + { + /* Remember that we saw the `goto' keyword. */ + goto_p = true; + /* Consume the token. */ + cp_lexer_consume_token (parser->lexer); + } + else + done = true; + break; + default: + done = true; + } + /* Look for the opening `('. */ if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN)) return; -- 1.8.3.1 ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/2] asm qualifiers (PR55681) 2018-10-30 18:56 ` [PATCH 1/2] asm qualifiers (PR55681) Segher Boessenkool @ 2018-11-29 13:35 ` Segher Boessenkool 2018-11-29 21:13 ` Joseph Myers 0 siblings, 1 reply; 23+ messages in thread From: Segher Boessenkool @ 2018-11-29 13:35 UTC (permalink / raw) To: gcc-patches; +Cc: jakub, joseph, polacek, jason, nathan +cc: C and C++ maintainers. Sorry I forgot before :-/ On Tue, Oct 30, 2018 at 05:30:33PM +0000, Segher Boessenkool wrote: > PR55681 observes that currently only one qualifier is allowed for > inline asm, so that e.g. "volatile asm" is allowed, "const asm" is also > okay (with a warning), but "const volatile asm" gives an error. Also > "const const asm" is an error (while "const const int" is okay for C), > "goto" has to be last, and "_Atomic" isn't handled at all. > > This patch fixes all these. It allows any order of qualifiers (and > goto), allows them all for C, allows duplications for C. For C++ it > still allows only a single volatile and single goto, but in any order. > > > 2018-10-30 Segher Boessenkool <segher@kernel.crashing.org> > > gcc/c/ > PR inline-asm/55681 > * c-parser.c (c_parser_for_statement): Update grammar. Allow any > combination of type-qualifiers and goto in any order, with repetitions > allowed. > > gcc/cp/ > PR inline-asm/55681 > * parser.c (cp_parser_using_directive): Update grammar. Allow any > combination of volatile and goto in any order, without repetitions. > > --- > gcc/c/c-parser.c | 66 +++++++++++++++++++++++++++--------------------- > gcc/cp/parser.c | 77 +++++++++++++++++++++++++++++++++++++------------------- > 2 files changed, 89 insertions(+), 54 deletions(-) > > diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c > index ee66ce8..ce9921e 100644 > --- a/gcc/c/c-parser.c > +++ b/gcc/c/c-parser.c > @@ -6283,23 +6283,31 @@ c_parser_for_statement (c_parser *parser, bool ivdep, unsigned short unroll, > } > > /* Parse an asm statement, a GNU extension. This is a full-blown asm > - statement with inputs, outputs, clobbers, and volatile tag > + statement with inputs, outputs, clobbers, and volatile and goto tag > allowed. > > + asm-qualifier: > + type-qualifier > + goto > + > + asm-qualifier-list: > + asm-qualifier-list asm-qualifier > + asm-qualifier > + > asm-statement: > - asm type-qualifier[opt] ( asm-argument ) ; > - asm type-qualifier[opt] goto ( asm-goto-argument ) ; > + asm asm-qualifier-list[opt] ( asm-argument ) ; > > asm-argument: > asm-string-literal > asm-string-literal : asm-operands[opt] > asm-string-literal : asm-operands[opt] : asm-operands[opt] > - asm-string-literal : asm-operands[opt] : asm-operands[opt] : asm-clobbers[opt] > - > - asm-goto-argument: > + asm-string-literal : asm-operands[opt] : asm-operands[opt] \ > + : asm-clobbers[opt] > asm-string-literal : : asm-operands[opt] : asm-clobbers[opt] \ > : asm-goto-operands > > + The form with asm-goto-operands is valid if and only if the > + asm-qualifier-list contains goto, and is the only allowed form in that case. > Qualifiers other than volatile are accepted in the syntax but > warned for. */ > > @@ -6313,30 +6321,32 @@ c_parser_asm_statement (c_parser *parser) > > gcc_assert (c_parser_next_token_is_keyword (parser, RID_ASM)); > c_parser_consume_token (parser); > - if (c_parser_next_token_is_keyword (parser, RID_VOLATILE)) > - { > - quals = c_parser_peek_token (parser)->value; > - c_parser_consume_token (parser); > - } > - else if (c_parser_next_token_is_keyword (parser, RID_CONST) > - || c_parser_next_token_is_keyword (parser, RID_RESTRICT)) > - { > - warning_at (c_parser_peek_token (parser)->location, > - 0, > - "%E qualifier ignored on asm", > - c_parser_peek_token (parser)->value); > - quals = NULL_TREE; > - c_parser_consume_token (parser); > - } > - else > - quals = NULL_TREE; > > + quals = NULL_TREE; > is_goto = false; > - if (c_parser_next_token_is_keyword (parser, RID_GOTO)) > - { > - c_parser_consume_token (parser); > - is_goto = true; > - } > + for (bool done = false; !done; ) > + switch (c_parser_peek_token (parser)->keyword) > + { > + case RID_VOLATILE: > + quals = c_parser_peek_token (parser)->value; > + c_parser_consume_token (parser); > + break; > + case RID_CONST: > + case RID_RESTRICT: > + case RID_ATOMIC: > + warning_at (c_parser_peek_token (parser)->location, > + 0, > + "%E qualifier ignored on asm", > + c_parser_peek_token (parser)->value); > + c_parser_consume_token (parser); > + break; > + case RID_GOTO: > + is_goto = true; > + c_parser_consume_token (parser); > + break; > + default: > + done = true; > + } > > /* ??? Follow the C++ parser rather than using the > lex_untranslated_string kludge. */ > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c > index ebe326e..d44fd4d 100644 > --- a/gcc/cp/parser.c > +++ b/gcc/cp/parser.c > @@ -19196,22 +19196,34 @@ cp_parser_using_directive (cp_parser* parser) > > /* Parse an asm-definition. > > + asm-qualifier: > + volatile > + goto > + > + asm-qualifier-list: > + asm-qualifier > + asm-qualifier-list asm-qualifier > + > asm-definition: > asm ( string-literal ) ; > > GNU Extension: > > asm-definition: > - asm volatile [opt] ( string-literal ) ; > - asm volatile [opt] ( string-literal : asm-operand-list [opt] ) ; > - asm volatile [opt] ( string-literal : asm-operand-list [opt] > - : asm-operand-list [opt] ) ; > - asm volatile [opt] ( string-literal : asm-operand-list [opt] > - : asm-operand-list [opt] > + asm asm-qualifier-list [opt] ( string-literal ) ; > + asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt] ) ; > + asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt] > + : asm-operand-list [opt] ) ; > + asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt] > + : asm-operand-list [opt] > : asm-clobber-list [opt] ) ; > - asm volatile [opt] goto ( string-literal : : asm-operand-list [opt] > - : asm-clobber-list [opt] > - : asm-goto-list ) ; */ > + asm asm-qualifier-list [opt] ( string-literal : : asm-operand-list [opt] > + : asm-clobber-list [opt] > + : asm-goto-list ) ; > + > + The form with asm-goto-list is valid if and only if the asm-qualifier-list > + contains goto, and is the only allowed form in that case. No duplicates are > + allowed in an asm-qualifier-list. */ > > static void > cp_parser_asm_definition (cp_parser* parser) > @@ -19240,23 +19252,36 @@ cp_parser_asm_definition (cp_parser* parser) > } > > /* See if the next token is `volatile'. */ > - if (cp_parser_allow_gnu_extensions_p (parser) > - && cp_lexer_next_token_is_keyword (parser->lexer, RID_VOLATILE)) > - { > - /* Remember that we saw the `volatile' keyword. */ > - volatile_p = true; > - /* Consume the token. */ > - cp_lexer_consume_token (parser->lexer); > - } > - if (cp_parser_allow_gnu_extensions_p (parser) > - && parser->in_function_body > - && cp_lexer_next_token_is_keyword (parser->lexer, RID_GOTO)) > - { > - /* Remember that we saw the `goto' keyword. */ > - goto_p = true; > - /* Consume the token. */ > - cp_lexer_consume_token (parser->lexer); > - } > + if (cp_parser_allow_gnu_extensions_p (parser)) > + for (bool done = false; !done ; ) > + switch (cp_lexer_peek_token (parser->lexer)->keyword) > + { > + case RID_VOLATILE: > + if (!volatile_p) > + { > + /* Remember that we saw the `volatile' keyword. */ > + volatile_p = true; > + /* Consume the token. */ > + cp_lexer_consume_token (parser->lexer); > + } > + else > + done = true; > + break; > + case RID_GOTO: > + if (!goto_p && parser->in_function_body) > + { > + /* Remember that we saw the `goto' keyword. */ > + goto_p = true; > + /* Consume the token. */ > + cp_lexer_consume_token (parser->lexer); > + } > + else > + done = true; > + break; > + default: > + done = true; > + } > + > /* Look for the opening `('. */ > if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN)) > return; > -- > 1.8.3.1 ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/2] asm qualifiers (PR55681) 2018-11-29 13:35 ` Segher Boessenkool @ 2018-11-29 21:13 ` Joseph Myers 2018-11-29 22:22 ` Segher Boessenkool 0 siblings, 1 reply; 23+ messages in thread From: Joseph Myers @ 2018-11-29 21:13 UTC (permalink / raw) To: Segher Boessenkool; +Cc: gcc-patches, jakub, polacek, jason, nathan I'd expect testcases to be added for the new syntax variants (duplicate qualifiers / goto and new orderings thereof). There's a description of the syntax in extend.texi: @example asm @r{[}volatile@r{]} ( @var{AssemblerTemplate} : @var{OutputOperands} @r{[} : @var{InputOperands} @r{[} : @var{Clobbers} @r{]} @r{]}) asm @r{[}volatile@r{]} goto ( @var{AssemblerTemplate} : : @var{InputOperands} : @var{Clobbers} : @var{GotoLabels}) @end example I'd expect this to be updated by this patch, and again by the "asm inline" one. What's the basis for allowing duplicates for C but not for C++? -- Joseph S. Myers joseph@codesourcery.com ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/2] asm qualifiers (PR55681) 2018-11-29 21:13 ` Joseph Myers @ 2018-11-29 22:22 ` Segher Boessenkool 2018-11-29 23:14 ` Joseph Myers 0 siblings, 1 reply; 23+ messages in thread From: Segher Boessenkool @ 2018-11-29 22:22 UTC (permalink / raw) To: Joseph Myers; +Cc: gcc-patches, jakub, polacek, jason, nathan On Thu, Nov 29, 2018 at 09:13:13PM +0000, Joseph Myers wrote: > I'd expect testcases to be added for the new syntax variants (duplicate > qualifiers / goto and new orderings thereof). Okay. > There's a description of the syntax in extend.texi: > > @example > asm @r{[}volatile@r{]} ( @var{AssemblerTemplate} > : @var{OutputOperands} > @r{[} : @var{InputOperands} > @r{[} : @var{Clobbers} @r{]} @r{]}) > > asm @r{[}volatile@r{]} goto ( @var{AssemblerTemplate} > : > : @var{InputOperands} > : @var{Clobbers} > : @var{GotoLabels}) > @end example > > I'd expect this to be updated by this patch, and again by the "asm inline" > one. That stuff needs to be rewritten :-( But I'll see what I can do. > What's the basis for allowing duplicates for C but not for C++? It is the status quo. It would make sense to allow duplicates for C++ as well, sure. If that is preferred I can make a patch for it? Segher ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/2] asm qualifiers (PR55681) 2018-11-29 22:22 ` Segher Boessenkool @ 2018-11-29 23:14 ` Joseph Myers 2018-11-30 0:03 ` Segher Boessenkool 0 siblings, 1 reply; 23+ messages in thread From: Joseph Myers @ 2018-11-29 23:14 UTC (permalink / raw) To: Segher Boessenkool; +Cc: gcc-patches, jakub, polacek, jason, nathan On Thu, 29 Nov 2018, Segher Boessenkool wrote: > > What's the basis for allowing duplicates for C but not for C++? > > It is the status quo. It would make sense to allow duplicates for C++ as > well, sure. If that is preferred I can make a patch for it? Duplicate qualifiers are allowed *in declarations* for C (as per C99). They aren't allowed in asm. I'd think the most obvious thing would be not to allow duplicate qualifiers in asm at all (but still allow any ordering of volatile, goto and inline). Essentially, the use in asm is just reusing a keyword in a different context, so I don't think duplicates being allowed in declarations is relevant to allowing them in asm (any more than it indicates that __attribute__ ((const const const)) should be allowed just because const is a valid attribute). -- Joseph S. Myers joseph@codesourcery.com ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/2] asm qualifiers (PR55681) 2018-11-29 23:14 ` Joseph Myers @ 2018-11-30 0:03 ` Segher Boessenkool 2018-11-30 0:11 ` Joseph Myers 0 siblings, 1 reply; 23+ messages in thread From: Segher Boessenkool @ 2018-11-30 0:03 UTC (permalink / raw) To: Joseph Myers; +Cc: gcc-patches, jakub, polacek, jason, nathan On Thu, Nov 29, 2018 at 11:14:45PM +0000, Joseph Myers wrote: > On Thu, 29 Nov 2018, Segher Boessenkool wrote: > > > > What's the basis for allowing duplicates for C but not for C++? > > > > It is the status quo. It would make sense to allow duplicates for C++ as > > well, sure. If that is preferred I can make a patch for it? > > Duplicate qualifiers are allowed *in declarations* for C (as per C99). And I used type-qualifier-list[opt] there, to start with. > They aren't allowed in asm. I'd think the most obvious thing would be not > to allow duplicate qualifiers in asm at all (but still allow any ordering > of volatile, goto and inline). Essentially, the use in asm is just > reusing a keyword in a different context, so I don't think duplicates > being allowed in declarations is relevant to allowing them in asm (any > more than it indicates that __attribute__ ((const const const)) should be > allowed just because const is a valid attribute). So "asm const restrict" is allowed, but "asm const const restrict" isn't. Hrm. That means we'll have to keep track of the ignored qualifiers. (There aren't any ignored asm qualifiers in C++ so no such issue there). What do you want done with const and restrict (and _Atomic, which is allowed by the current grammar)? Segher ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/2] asm qualifiers (PR55681) 2018-11-30 0:03 ` Segher Boessenkool @ 2018-11-30 0:11 ` Joseph Myers 2018-11-30 0:21 ` Segher Boessenkool 0 siblings, 1 reply; 23+ messages in thread From: Joseph Myers @ 2018-11-30 0:11 UTC (permalink / raw) To: Segher Boessenkool; +Cc: gcc-patches, jakub, polacek, jason, nathan On Thu, 29 Nov 2018, Segher Boessenkool wrote: > So "asm const restrict" is allowed, but "asm const const restrict" isn't. No, asm const restrict isn't allowed. volatile is allowed; const and restrict are allowed with warnings because that replicates what the old bison parser allowed; but at most one qualifier is allowed at present. > What do you want done with const and restrict (and _Atomic, which is > allowed by the current grammar)? Don't allow _Atomic, since it's not allowed at present. Either allow at most one qualifier (being one of volatile / const / restrict) or remove support for const and restrict there and just allow (at most one) volatile. -- Joseph S. Myers joseph@codesourcery.com ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/2] asm qualifiers (PR55681) 2018-11-30 0:11 ` Joseph Myers @ 2018-11-30 0:21 ` Segher Boessenkool 0 siblings, 0 replies; 23+ messages in thread From: Segher Boessenkool @ 2018-11-30 0:21 UTC (permalink / raw) To: Joseph Myers; +Cc: gcc-patches, jakub, polacek, jason, nathan On Fri, Nov 30, 2018 at 12:11:30AM +0000, Joseph Myers wrote: > On Thu, 29 Nov 2018, Segher Boessenkool wrote: > > > So "asm const restrict" is allowed, but "asm const const restrict" isn't. > > No, asm const restrict isn't allowed. volatile is allowed; const and > restrict are allowed with warnings because that replicates what the old > bison parser allowed; but at most one qualifier is allowed at present. I mean the wanted behaviour, not the current behaviour. > > What do you want done with const and restrict (and _Atomic, which is > > allowed by the current grammar)? > > Don't allow _Atomic, since it's not allowed at present. Either allow at > most one qualifier (being one of volatile / const / restrict) or remove > support for const and restrict there and just allow (at most one) > volatile. I'll go for the latter. That also harmonises C and C++ here. Thanks! Segher ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 0/2] asm qualifiers (PR55681) and asm input 2018-10-30 18:01 [PATCH 0/2] asm qualifiers (PR55681) and asm input Segher Boessenkool 2018-10-30 18:41 ` [PATCH 2/2] asm inline Segher Boessenkool 2018-10-30 18:56 ` [PATCH 1/2] asm qualifiers (PR55681) Segher Boessenkool @ 2018-11-11 0:33 ` Segher Boessenkool 2018-11-17 14:53 ` Segher Boessenkool 2 siblings, 1 reply; 23+ messages in thread From: Segher Boessenkool @ 2018-11-11 0:33 UTC (permalink / raw) To: gcc-patches; +Cc: jakub Ping. On Tue, Oct 30, 2018 at 05:30:32PM +0000, Segher Boessenkool wrote: > Hi! > > This is the same "asm input" patch as before, but now preceded by a patch > that makes all orderings of volatile/goto/inline valid, also the other type > qualifiers for C, and also repetitions for C. > > Tested on powerpc64-linux {-m32,-m64}. Is this okay for trunk? > > > Segher > > > gcc/c/c-parser.c | 79 ++++++++++++--------- > gcc/c/c-tree.h | 3 +- > gcc/c/c-typeck.c | 3 +- > gcc/cp/cp-tree.h | 2 +- > gcc/cp/parser.c | 92 +++++++++++++++++-------- > gcc/cp/pt.c | 2 +- > gcc/cp/semantics.c | 3 +- > gcc/doc/extend.texi | 10 ++- > gcc/gimple-pretty-print.c | 2 + > gcc/gimple.h | 24 ++++++- > gcc/gimplify.c | 1 + > gcc/ipa-icf-gimple.c | 3 + > gcc/testsuite/c-c++-common/torture/asm-inline.c | 53 ++++++++++++++ > gcc/tree-core.h | 3 + > gcc/tree-inline.c | 3 + > gcc/tree.h | 3 + > 16 files changed, 221 insertions(+), 65 deletions(-) > create mode 100644 gcc/testsuite/c-c++-common/torture/asm-inline.c > > -- > 1.8.3.1 ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 0/2] asm qualifiers (PR55681) and asm input 2018-11-11 0:33 ` [PATCH 0/2] asm qualifiers (PR55681) and asm input Segher Boessenkool @ 2018-11-17 14:53 ` Segher Boessenkool 2018-11-29 12:27 ` [ping x3] Re: [PATCH 0/2] asm qualifiers (PR55681) and asm inline Segher Boessenkool 0 siblings, 1 reply; 23+ messages in thread From: Segher Boessenkool @ 2018-11-17 14:53 UTC (permalink / raw) To: gcc-patches; +Cc: jakub Ping x2. On Sat, Nov 10, 2018 at 06:33:37PM -0600, Segher Boessenkool wrote: > Ping. > > On Tue, Oct 30, 2018 at 05:30:32PM +0000, Segher Boessenkool wrote: > > Hi! > > > > This is the same "asm input" patch as before, but now preceded by a patch > > that makes all orderings of volatile/goto/inline valid, also the other type > > qualifiers for C, and also repetitions for C. > > > > Tested on powerpc64-linux {-m32,-m64}. Is this okay for trunk? > > > > > > Segher > > > > > > gcc/c/c-parser.c | 79 ++++++++++++--------- > > gcc/c/c-tree.h | 3 +- > > gcc/c/c-typeck.c | 3 +- > > gcc/cp/cp-tree.h | 2 +- > > gcc/cp/parser.c | 92 +++++++++++++++++-------- > > gcc/cp/pt.c | 2 +- > > gcc/cp/semantics.c | 3 +- > > gcc/doc/extend.texi | 10 ++- > > gcc/gimple-pretty-print.c | 2 + > > gcc/gimple.h | 24 ++++++- > > gcc/gimplify.c | 1 + > > gcc/ipa-icf-gimple.c | 3 + > > gcc/testsuite/c-c++-common/torture/asm-inline.c | 53 ++++++++++++++ > > gcc/tree-core.h | 3 + > > gcc/tree-inline.c | 3 + > > gcc/tree.h | 3 + > > 16 files changed, 221 insertions(+), 65 deletions(-) > > create mode 100644 gcc/testsuite/c-c++-common/torture/asm-inline.c > > > > -- > > 1.8.3.1 ^ permalink raw reply [flat|nested] 23+ messages in thread
* [ping x3] Re: [PATCH 0/2] asm qualifiers (PR55681) and asm inline 2018-11-17 14:53 ` Segher Boessenkool @ 2018-11-29 12:27 ` Segher Boessenkool 0 siblings, 0 replies; 23+ messages in thread From: Segher Boessenkool @ 2018-11-29 12:27 UTC (permalink / raw) To: gcc-patches; +Cc: jakub Ping x3. On Sat, Nov 17, 2018 at 08:52:58AM -0600, Segher Boessenkool wrote: > Ping x2. > > On Sat, Nov 10, 2018 at 06:33:37PM -0600, Segher Boessenkool wrote: > > Ping. > > > > On Tue, Oct 30, 2018 at 05:30:32PM +0000, Segher Boessenkool wrote: > > > Hi! > > > > > > This is the same "asm input" patch as before, but now preceded by a patch > > > that makes all orderings of volatile/goto/inline valid, also the other type > > > qualifiers for C, and also repetitions for C. > > > > > > Tested on powerpc64-linux {-m32,-m64}. Is this okay for trunk? > > > > > > > > > Segher > > > > > > > > > gcc/c/c-parser.c | 79 ++++++++++++--------- > > > gcc/c/c-tree.h | 3 +- > > > gcc/c/c-typeck.c | 3 +- > > > gcc/cp/cp-tree.h | 2 +- > > > gcc/cp/parser.c | 92 +++++++++++++++++-------- > > > gcc/cp/pt.c | 2 +- > > > gcc/cp/semantics.c | 3 +- > > > gcc/doc/extend.texi | 10 ++- > > > gcc/gimple-pretty-print.c | 2 + > > > gcc/gimple.h | 24 ++++++- > > > gcc/gimplify.c | 1 + > > > gcc/ipa-icf-gimple.c | 3 + > > > gcc/testsuite/c-c++-common/torture/asm-inline.c | 53 ++++++++++++++ > > > gcc/tree-core.h | 3 + > > > gcc/tree-inline.c | 3 + > > > gcc/tree.h | 3 + > > > 16 files changed, 221 insertions(+), 65 deletions(-) > > > create mode 100644 gcc/testsuite/c-c++-common/torture/asm-inline.c > > > > > > -- > > > 1.8.3.1 ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH v2 0/2] asm qualifiers (PR55681) and asm inline
@ 2018-12-02 16:38 Segher Boessenkool
2018-12-02 16:39 ` [PATCH 1/2] asm qualifiers (PR55681) Segher Boessenkool
0 siblings, 1 reply; 23+ messages in thread
From: Segher Boessenkool @ 2018-12-02 16:38 UTC (permalink / raw)
To: gcc-patches
Cc: jakub, Joseph Myers, jason, nathan, polacek, Segher Boessenkool
Hi!
v2, with the input from Joseph taken into account.
This is the same "asm inline" patch as before, but now preceded by a
patch that makes all orderings of volatile/goto/inline valid, all other
type qualifiers invalid, all repetitions of qualifiers invalid.
Tested on powerpc64-linux {-m32,-m64}. Is this okay for trunk?
Segher
gcc/c/c-parser.c | 91 +++++++++++++++---------
gcc/c/c-tree.h | 3 +-
gcc/c/c-typeck.c | 3 +-
gcc/cp/cp-tree.h | 2 +-
gcc/cp/parser.c | 92 +++++++++++++++++--------
gcc/cp/pt.c | 2 +-
gcc/cp/semantics.c | 3 +-
gcc/doc/extend.texi | 23 +++++--
gcc/gimple-pretty-print.c | 2 +
gcc/gimple.h | 24 ++++++-
gcc/gimplify.c | 1 +
gcc/ipa-icf-gimple.c | 3 +
gcc/testsuite/c-c++-common/torture/asm-inline.c | 53 ++++++++++++++
gcc/testsuite/gcc.dg/asm-qual-1.c | 10 ++-
gcc/testsuite/gcc.dg/asm-qual-2.c | 46 +++++++++++++
gcc/tree-core.h | 3 +
gcc/tree-inline.c | 3 +
gcc/tree.h | 3 +
18 files changed, 294 insertions(+), 73 deletions(-)
create mode 100644 gcc/testsuite/c-c++-common/torture/asm-inline.c
create mode 100644 gcc/testsuite/gcc.dg/asm-qual-2.c
--
1.8.3.1
^ permalink raw reply [flat|nested] 23+ messages in thread* [PATCH 1/2] asm qualifiers (PR55681) 2018-12-02 16:38 [PATCH v2 " Segher Boessenkool @ 2018-12-02 16:39 ` Segher Boessenkool 2018-12-03 22:20 ` Joseph Myers 2018-12-05 21:47 ` Jason Merrill 0 siblings, 2 replies; 23+ messages in thread From: Segher Boessenkool @ 2018-12-02 16:39 UTC (permalink / raw) To: gcc-patches Cc: jakub, Joseph Myers, jason, nathan, polacek, Segher Boessenkool PR55681 observes that currently only one qualifier is allowed for inline asm, so that e.g. "volatile asm" is allowed, "const asm" is also okay (with a warning), but "const volatile asm" gives an error. Also "goto" has to be last. This patch changes things so that only "asm-qualifiers" are allowed, that is "volatile" and "goto", in any combination, in any order, but without repetitions. 2018-12-02 Segher Boessenkool <segher@kernel.crashing.org> PR inline-asm/55681 * doc/extend.texi (Basic Asm): Update grammar. (Extended Asm): Update grammar. gcc/c/ PR inline-asm/55681 * c-parser.c (c_parser_for_statement): Update grammar. Allow any combination of volatile and goto, in any order, without repetitions. gcc/cp/ PR inline-asm/55681 * parser.c (cp_parser_using_directive): Update grammar. Allow any combination of volatile and goto, in any order, without repetitions. gcc/testsuite/ PR inline-asm/55681 * gcc.dg/asm-qual-1.c: Test that "const" and "restrict" are refused. * gcc.dg/asm-qual-2.c: New test, test that asm-qualifiers are allowed in any order, but that duplicates are not allowed. --- gcc/c/c-parser.c | 74 +++++++++++++++++++++---------------- gcc/cp/parser.c | 77 ++++++++++++++++++++++++++------------- gcc/doc/extend.texi | 8 ++-- gcc/testsuite/gcc.dg/asm-qual-1.c | 10 +++-- gcc/testsuite/gcc.dg/asm-qual-2.c | 21 +++++++++++ 5 files changed, 127 insertions(+), 63 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/asm-qual-2.c diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c index afc4071..e516f9a 100644 --- a/gcc/c/c-parser.c +++ b/gcc/c/c-parser.c @@ -6329,60 +6329,72 @@ c_parser_for_statement (c_parser *parser, bool ivdep, unsigned short unroll, } /* Parse an asm statement, a GNU extension. This is a full-blown asm - statement with inputs, outputs, clobbers, and volatile tag + statement with inputs, outputs, clobbers, and volatile and goto tag allowed. + asm-qualifier: + volatile + goto + + asm-qualifier-list: + asm-qualifier-list asm-qualifier + asm-qualifier + asm-statement: - asm type-qualifier[opt] ( asm-argument ) ; - asm type-qualifier[opt] goto ( asm-goto-argument ) ; + asm asm-qualifier-list[opt] ( asm-argument ) ; asm-argument: asm-string-literal asm-string-literal : asm-operands[opt] asm-string-literal : asm-operands[opt] : asm-operands[opt] - asm-string-literal : asm-operands[opt] : asm-operands[opt] : asm-clobbers[opt] - - asm-goto-argument: + asm-string-literal : asm-operands[opt] : asm-operands[opt] \ + : asm-clobbers[opt] asm-string-literal : : asm-operands[opt] : asm-clobbers[opt] \ : asm-goto-operands - Qualifiers other than volatile are accepted in the syntax but - warned for. */ + The form with asm-goto-operands is valid if and only if the + asm-qualifier-list contains goto, and is the only allowed form in that case. + Duplicate asm-qualifiers are not allowed. */ static tree c_parser_asm_statement (c_parser *parser) { tree quals, str, outputs, inputs, clobbers, labels, ret; - bool simple, is_goto; + bool simple, is_volatile, is_goto; location_t asm_loc = c_parser_peek_token (parser)->location; int section, nsections; gcc_assert (c_parser_next_token_is_keyword (parser, RID_ASM)); c_parser_consume_token (parser); - if (c_parser_next_token_is_keyword (parser, RID_VOLATILE)) - { - quals = c_parser_peek_token (parser)->value; - c_parser_consume_token (parser); - } - else if (c_parser_next_token_is_keyword (parser, RID_CONST) - || c_parser_next_token_is_keyword (parser, RID_RESTRICT)) - { - warning_at (c_parser_peek_token (parser)->location, - 0, - "%E qualifier ignored on asm", - c_parser_peek_token (parser)->value); - quals = NULL_TREE; - c_parser_consume_token (parser); - } - else - quals = NULL_TREE; + quals = NULL_TREE; + is_volatile = false; is_goto = false; - if (c_parser_next_token_is_keyword (parser, RID_GOTO)) - { - c_parser_consume_token (parser); - is_goto = true; - } + for (bool done = false; !done; ) + switch (c_parser_peek_token (parser)->keyword) + { + case RID_VOLATILE: + if (!is_volatile) + { + is_volatile = true; + quals = c_parser_peek_token (parser)->value; + c_parser_consume_token (parser); + } + else + done = true; + break; + case RID_GOTO: + if (!is_goto) + { + is_goto = true; + c_parser_consume_token (parser); + } + else + done = true; + break; + default: + done = true; + } /* ??? Follow the C++ parser rather than using the lex_untranslated_string kludge. */ diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index 3a98ed9..9c43683 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -19537,22 +19537,34 @@ cp_parser_using_directive (cp_parser* parser) /* Parse an asm-definition. + asm-qualifier: + volatile + goto + + asm-qualifier-list: + asm-qualifier + asm-qualifier-list asm-qualifier + asm-definition: asm ( string-literal ) ; GNU Extension: asm-definition: - asm volatile [opt] ( string-literal ) ; - asm volatile [opt] ( string-literal : asm-operand-list [opt] ) ; - asm volatile [opt] ( string-literal : asm-operand-list [opt] - : asm-operand-list [opt] ) ; - asm volatile [opt] ( string-literal : asm-operand-list [opt] - : asm-operand-list [opt] + asm asm-qualifier-list [opt] ( string-literal ) ; + asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt] ) ; + asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt] + : asm-operand-list [opt] ) ; + asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt] + : asm-operand-list [opt] : asm-clobber-list [opt] ) ; - asm volatile [opt] goto ( string-literal : : asm-operand-list [opt] - : asm-clobber-list [opt] - : asm-goto-list ) ; */ + asm asm-qualifier-list [opt] ( string-literal : : asm-operand-list [opt] + : asm-clobber-list [opt] + : asm-goto-list ) ; + + The form with asm-goto-list is valid if and only if the asm-qualifier-list + contains goto, and is the only allowed form in that case. No duplicates are + allowed in an asm-qualifier-list. */ static void cp_parser_asm_definition (cp_parser* parser) @@ -19581,23 +19593,36 @@ cp_parser_asm_definition (cp_parser* parser) } /* See if the next token is `volatile'. */ - if (cp_parser_allow_gnu_extensions_p (parser) - && cp_lexer_next_token_is_keyword (parser->lexer, RID_VOLATILE)) - { - /* Remember that we saw the `volatile' keyword. */ - volatile_p = true; - /* Consume the token. */ - cp_lexer_consume_token (parser->lexer); - } - if (cp_parser_allow_gnu_extensions_p (parser) - && parser->in_function_body - && cp_lexer_next_token_is_keyword (parser->lexer, RID_GOTO)) - { - /* Remember that we saw the `goto' keyword. */ - goto_p = true; - /* Consume the token. */ - cp_lexer_consume_token (parser->lexer); - } + if (cp_parser_allow_gnu_extensions_p (parser)) + for (bool done = false; !done ; ) + switch (cp_lexer_peek_token (parser->lexer)->keyword) + { + case RID_VOLATILE: + if (!volatile_p) + { + /* Remember that we saw the `volatile' keyword. */ + volatile_p = true; + /* Consume the token. */ + cp_lexer_consume_token (parser->lexer); + } + else + done = true; + break; + case RID_GOTO: + if (!goto_p && parser->in_function_body) + { + /* Remember that we saw the `goto' keyword. */ + goto_p = true; + /* Consume the token. */ + cp_lexer_consume_token (parser->lexer); + } + else + done = true; + break; + default: + done = true; + } + /* Look for the opening `('. */ if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN)) return; diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 4e8be5b..2791f25 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -8369,7 +8369,7 @@ for a C symbol, or to place a C variable in a specific register. A basic @code{asm} statement has the following syntax: @example -asm @r{[} volatile @r{]} ( @var{AssemblerInstructions} ) +asm @var{asm-qualifiers} ( @var{AssemblerInstructions} ) @end example The @code{asm} keyword is a GNU extension. @@ -8497,17 +8497,19 @@ Extended @code{asm} syntax uses colons (@samp{:}) to delimit the operand parameters after the assembler template: @example -asm @r{[}volatile@r{]} ( @var{AssemblerTemplate} +asm @var{asm-qualifiers} ( @var{AssemblerTemplate} : @var{OutputOperands} @r{[} : @var{InputOperands} @r{[} : @var{Clobbers} @r{]} @r{]}) -asm @r{[}volatile@r{]} goto ( @var{AssemblerTemplate} +asm @var{asm-qualifiers} ( @var{AssemblerTemplate} : : @var{InputOperands} : @var{Clobbers} : @var{GotoLabels}) @end example +where in the last form, @var{asm-qualifiers} contains @code{goto} (and in the +first form, not). The @code{asm} keyword is a GNU extension. When writing code that can be compiled with @option{-ansi} and the diff --git a/gcc/testsuite/gcc.dg/asm-qual-1.c b/gcc/testsuite/gcc.dg/asm-qual-1.c index 5ec9a29..cb37283 100644 --- a/gcc/testsuite/gcc.dg/asm-qual-1.c +++ b/gcc/testsuite/gcc.dg/asm-qual-1.c @@ -1,4 +1,4 @@ -/* Test that qualifiers other than volatile are ignored on asm. */ +/* Test that qualifiers other than volatile are disallowed on asm. */ /* Origin: Joseph Myers <joseph@codesourcery.com> */ /* { dg-do compile } */ /* { dg-options "-std=gnu99" } */ @@ -7,6 +7,10 @@ void f (void) { asm volatile (""); - asm const (""); /* { dg-warning "const qualifier ignored on asm" } */ - asm restrict (""); /* { dg-warning "restrict qualifier ignored on asm" } */ + + asm const (""); /* { dg-error {expected '\(' before 'const'} } */ + /* { dg-error {expected identifier} {} {target *-*-*} .-1 } */ + + asm restrict (""); /* { dg-error {expected '\(' before 'restrict'} } */ + /* { dg-error {expected identifier} {} {target *-*-*} .-1 } */ } diff --git a/gcc/testsuite/gcc.dg/asm-qual-2.c b/gcc/testsuite/gcc.dg/asm-qual-2.c new file mode 100644 index 0000000..37df2ad --- /dev/null +++ b/gcc/testsuite/gcc.dg/asm-qual-2.c @@ -0,0 +1,21 @@ +/* Test that qualifiers on asm are allowed in any order. */ +/* { dg-do compile } */ +/* { dg-options "-std=gnu99" } */ + +void +f (void) +{ + asm volatile goto ("" :::: lab); + asm goto volatile ("" :::: lab); + + /* Duplicates are not allowed. */ + asm goto volatile volatile ("" :::: lab); /* { dg-error "" } */ + asm volatile goto volatile ("" :::: lab); /* { dg-error "" } */ + asm volatile volatile goto ("" :::: lab); /* { dg-error "" } */ + asm goto goto volatile ("" :::: lab); /* { dg-error "" } */ + asm goto volatile goto ("" :::: lab); /* { dg-error "" } */ + asm volatile goto goto ("" :::: lab); /* { dg-error "" } */ + +lab: + ; +} -- 1.8.3.1 ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/2] asm qualifiers (PR55681) 2018-12-02 16:39 ` [PATCH 1/2] asm qualifiers (PR55681) Segher Boessenkool @ 2018-12-03 22:20 ` Joseph Myers 2018-12-05 21:47 ` Jason Merrill 1 sibling, 0 replies; 23+ messages in thread From: Joseph Myers @ 2018-12-03 22:20 UTC (permalink / raw) To: Segher Boessenkool; +Cc: gcc-patches, jakub, jason, nathan, polacek On Sun, 2 Dec 2018, Segher Boessenkool wrote: > PR55681 observes that currently only one qualifier is allowed for > inline asm, so that e.g. "volatile asm" is allowed, "const asm" is also > okay (with a warning), but "const volatile asm" gives an error. Also > "goto" has to be last. > > This patch changes things so that only "asm-qualifiers" are allowed, > that is "volatile" and "goto", in any combination, in any order, but > without repetitions. The C front-end changes are OK. -- Joseph S. Myers joseph@codesourcery.com ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/2] asm qualifiers (PR55681) 2018-12-02 16:39 ` [PATCH 1/2] asm qualifiers (PR55681) Segher Boessenkool 2018-12-03 22:20 ` Joseph Myers @ 2018-12-05 21:47 ` Jason Merrill 2018-12-05 23:02 ` Segher Boessenkool 1 sibling, 1 reply; 23+ messages in thread From: Jason Merrill @ 2018-12-05 21:47 UTC (permalink / raw) To: Segher Boessenkool, gcc-patches; +Cc: jakub, Joseph Myers, nathan, polacek On 12/2/18 11:38 AM, Segher Boessenkool wrote: > PR55681 observes that currently only one qualifier is allowed for > inline asm, so that e.g. "volatile asm" is allowed, "const asm" is also > okay (with a warning), but "const volatile asm" gives an error. Also > "goto" has to be last. > > This patch changes things so that only "asm-qualifiers" are allowed, > that is "volatile" and "goto", in any combination, in any order, but > without repetitions. > > > 2018-12-02 Segher Boessenkool <segher@kernel.crashing.org> > > PR inline-asm/55681 > * doc/extend.texi (Basic Asm): Update grammar. > (Extended Asm): Update grammar. > > gcc/c/ > PR inline-asm/55681 > * c-parser.c (c_parser_for_statement): Update grammar. Allow any > combination of volatile and goto, in any order, without repetitions. > > gcc/cp/ > PR inline-asm/55681 > * parser.c (cp_parser_using_directive): Update grammar. Allow any > combination of volatile and goto, in any order, without repetitions. You don't actually change cp_parser_using_directive, despite what diff says: you're changing cp_parser_asm_definition. > + for (bool done = false; !done ; ) > + switch (cp_lexer_peek_token (parser->lexer)->keyword) > + { > + case RID_VOLATILE: > + if (!volatile_p) > + { > + /* Remember that we saw the `volatile' keyword. */ > + volatile_p = true; > + /* Consume the token. */ > + cp_lexer_consume_token (parser->lexer); > + } > + else > + done = true; > + break; > + case RID_GOTO: > + if (!goto_p && parser->in_function_body) > + { > + /* Remember that we saw the `goto' keyword. */ > + goto_p = true; > + /* Consume the token. */ > + cp_lexer_consume_token (parser->lexer); > + } > + else > + done = true; > + break; > + default: > + done = true; > + } An arguably simpler alternative to using the 'done' variable would be to 'break' out of the loop after the switch, and have the consume_token cases explicitly 'continue'. We also might remember the old tokens and give a more helpful error message in the case of duplicate keywords. But I won't insist on either of these, the C++ changes are OK as-is. Jason ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/2] asm qualifiers (PR55681) 2018-12-05 21:47 ` Jason Merrill @ 2018-12-05 23:02 ` Segher Boessenkool 0 siblings, 0 replies; 23+ messages in thread From: Segher Boessenkool @ 2018-12-05 23:02 UTC (permalink / raw) To: Jason Merrill; +Cc: gcc-patches, jakub, Joseph Myers, nathan, polacek Hi! On Wed, Dec 05, 2018 at 04:47:37PM -0500, Jason Merrill wrote: > On 12/2/18 11:38 AM, Segher Boessenkool wrote: > >PR55681 observes that currently only one qualifier is allowed for > >inline asm, so that e.g. "volatile asm" is allowed, "const asm" is also > >okay (with a warning), but "const volatile asm" gives an error. Also > >"goto" has to be last. > > > >This patch changes things so that only "asm-qualifiers" are allowed, > >that is "volatile" and "goto", in any combination, in any order, but > >without repetitions. > > > > > >2018-12-02 Segher Boessenkool <segher@kernel.crashing.org> > > > > PR inline-asm/55681 > > * doc/extend.texi (Basic Asm): Update grammar. > > (Extended Asm): Update grammar. > > > >gcc/c/ > > PR inline-asm/55681 > > * c-parser.c (c_parser_for_statement): Update grammar. Allow any > > combination of volatile and goto, in any order, without repetitions. > > > >gcc/cp/ > > PR inline-asm/55681 > > * parser.c (cp_parser_using_directive): Update grammar. Allow any > > combination of volatile and goto, in any order, without repetitions. > > You don't actually change cp_parser_using_directive, despite what diff > says: you're changing cp_parser_asm_definition. I trust diff too much, sigh. > >+ for (bool done = false; !done ; ) > >+ switch (cp_lexer_peek_token (parser->lexer)->keyword) > >+ { > >+ case RID_VOLATILE: > >+ if (!volatile_p) > >+ { > >+ /* Remember that we saw the `volatile' keyword. */ > >+ volatile_p = true; > >+ /* Consume the token. */ > >+ cp_lexer_consume_token (parser->lexer); > >+ } > >+ else > >+ done = true; > >+ break; > >+ case RID_GOTO: > >+ if (!goto_p && parser->in_function_body) > >+ { > >+ /* Remember that we saw the `goto' keyword. */ > >+ goto_p = true; > >+ /* Consume the token. */ > >+ cp_lexer_consume_token (parser->lexer); > >+ } > >+ else > >+ done = true; > >+ break; > >+ default: > >+ done = true; > >+ } > > An arguably simpler alternative to using the 'done' variable would be to > 'break' out of the loop after the switch, and have the consume_token > cases explicitly 'continue'. Yeah, that is neater, continue only deals with the loop. Nice. > We also might remember the old tokens and give a more helpful error > message in the case of duplicate keywords. > > But I won't insist on either of these, the C++ changes are OK as-is. I'll commit it like this then, and work on the improvements afterwards (they also apply to the C frontend). Thanks for the review! Segher ^ permalink raw reply [flat|nested] 23+ messages in thread
end of thread, other threads:[~2018-12-05 23:02 UTC | newest] Thread overview: 23+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-10-30 18:01 [PATCH 0/2] asm qualifiers (PR55681) and asm input Segher Boessenkool 2018-10-30 18:41 ` [PATCH 2/2] asm inline Segher Boessenkool 2018-10-30 18:58 ` Marek Polacek 2018-11-11 21:33 ` Martin Sebor 2018-11-11 22:01 ` Segher Boessenkool 2018-11-11 23:41 ` Martin Sebor 2018-11-12 0:19 ` Segher Boessenkool 2018-11-30 13:14 ` Richard Biener 2018-10-30 18:56 ` [PATCH 1/2] asm qualifiers (PR55681) Segher Boessenkool 2018-11-29 13:35 ` Segher Boessenkool 2018-11-29 21:13 ` Joseph Myers 2018-11-29 22:22 ` Segher Boessenkool 2018-11-29 23:14 ` Joseph Myers 2018-11-30 0:03 ` Segher Boessenkool 2018-11-30 0:11 ` Joseph Myers 2018-11-30 0:21 ` Segher Boessenkool 2018-11-11 0:33 ` [PATCH 0/2] asm qualifiers (PR55681) and asm input Segher Boessenkool 2018-11-17 14:53 ` Segher Boessenkool 2018-11-29 12:27 ` [ping x3] Re: [PATCH 0/2] asm qualifiers (PR55681) and asm inline Segher Boessenkool 2018-12-02 16:38 [PATCH v2 " Segher Boessenkool 2018-12-02 16:39 ` [PATCH 1/2] asm qualifiers (PR55681) Segher Boessenkool 2018-12-03 22:20 ` Joseph Myers 2018-12-05 21:47 ` Jason Merrill 2018-12-05 23:02 ` Segher Boessenkool
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