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* [gcc/devel/rust/master] Fix up missing jump_target handling
@ 2022-08-29 15:35 Thomas Schwinge
0 siblings, 0 replies; only message in thread
From: Thomas Schwinge @ 2022-08-29 15:35 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:49cddf6e588f443262958a60e0444abc4945834d
commit 49cddf6e588f443262958a60e0444abc4945834d
Author: Philip Herron <philip.herron@embecosm.com>
Date: Thu Aug 25 11:15:27 2022 +0100
Fix up missing jump_target handling
This adds in missed ported code for handling VAR_DECLS and jump's within
statement lists.
Diff:
---
gcc/rust/backend/rust-constexpr.cc | 172 +++++++++++++++++++++++++++--------
gcc/testsuite/rust/compile/const4.rs | 22 +++++
2 files changed, 157 insertions(+), 37 deletions(-)
diff --git a/gcc/rust/backend/rust-constexpr.cc b/gcc/rust/backend/rust-constexpr.cc
index 8c0f80b9e33..87b1a843493 100644
--- a/gcc/rust/backend/rust-constexpr.cc
+++ b/gcc/rust/backend/rust-constexpr.cc
@@ -88,6 +88,15 @@ unshare_constructor (tree t MEM_STAT_DECL);
void
maybe_save_constexpr_fundef (tree fun);
+static bool
+returns (tree *jump_target);
+static bool
+breaks (tree *jump_target);
+static bool
+continues (tree *jump_target);
+static bool
+switches (tree *jump_target);
+
struct constexpr_global_ctx
{
/* Values for any temporaries or local variables within the
@@ -1800,11 +1809,95 @@ eval_component_reference (const constexpr_ctx *ctx, tree t, bool lval,
overflow_p);
}
+/* Subroutine of cxx_eval_statement_list. Determine whether the statement
+ STMT matches *jump_target. If we're looking for a case label and we see
+ the default label, note it in ctx->css_state. */
+
+static bool
+label_matches (const constexpr_ctx *ctx, tree *jump_target, tree stmt)
+{
+ switch (TREE_CODE (*jump_target))
+ {
+ case LABEL_DECL:
+ if (TREE_CODE (stmt) == LABEL_EXPR
+ && LABEL_EXPR_LABEL (stmt) == *jump_target)
+ return true;
+ break;
+
+ case INTEGER_CST:
+ if (TREE_CODE (stmt) == CASE_LABEL_EXPR)
+ {
+ gcc_assert (ctx->css_state != NULL);
+ if (!CASE_LOW (stmt))
+ {
+ /* default: should appear just once in a SWITCH_EXPR
+ body (excluding nested SWITCH_EXPR). */
+ gcc_assert (*ctx->css_state != css_default_seen);
+ /* When evaluating SWITCH_EXPR body for the second time,
+ return true for the default: label. */
+ if (*ctx->css_state == css_default_processing)
+ return true;
+ *ctx->css_state = css_default_seen;
+ }
+ else if (CASE_HIGH (stmt))
+ {
+ if (tree_int_cst_le (CASE_LOW (stmt), *jump_target)
+ && tree_int_cst_le (*jump_target, CASE_HIGH (stmt)))
+ return true;
+ }
+ else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt)))
+ return true;
+ }
+ break;
+
+ case BREAK_STMT:
+ case CONTINUE_STMT:
+ /* These two are handled directly in cxx_eval_loop_expr by testing
+ breaks (jump_target) or continues (jump_target). */
+ break;
+
+ default:
+ gcc_unreachable ();
+ }
+ return false;
+}
+
static tree
eval_constant_expression (const constexpr_ctx *ctx, tree t, bool lval,
bool *non_constant_p, bool *overflow_p,
tree *jump_target /* = NULL */)
{
+ if (jump_target && *jump_target)
+ {
+ /* If we are jumping, ignore all statements/expressions except those
+ that could have LABEL_EXPR or CASE_LABEL_EXPR in their bodies. */
+ switch (TREE_CODE (t))
+ {
+ case BIND_EXPR:
+ case STATEMENT_LIST:
+ case LOOP_EXPR:
+ case COND_EXPR:
+ case IF_STMT:
+ case DO_STMT:
+ case WHILE_STMT:
+ case FOR_STMT:
+ break;
+ case LABEL_EXPR:
+ case CASE_LABEL_EXPR:
+ if (label_matches (ctx, jump_target, t))
+ /* Found it. */
+ *jump_target = NULL_TREE;
+ return NULL_TREE;
+ default:
+ return NULL_TREE;
+ }
+ }
+ if (error_operand_p (t))
+ {
+ *non_constant_p = true;
+ return t;
+ }
+
location_t loc = EXPR_LOCATION (t);
if (CONSTANT_CLASS_P (t))
@@ -1835,7 +1928,28 @@ eval_constant_expression (const constexpr_ctx *ctx, tree t, bool lval,
tree_code tcode = TREE_CODE (t);
switch (tcode)
{
+ case VAR_DECL:
+ if (DECL_HAS_VALUE_EXPR_P (t))
+ {
+ r = DECL_VALUE_EXPR (t);
+ return eval_constant_expression (ctx, r, lval, non_constant_p,
+ overflow_p);
+ }
+ /* fall through */
case CONST_DECL: {
+ /* We used to not check lval for CONST_DECL, but darwin.cc uses
+ CONST_DECL for aggregate constants. */
+ if (lval)
+ return t;
+ else if (t == ctx->object)
+ return ctx->ctor;
+ if (VAR_P (t))
+ if (tree *p = ctx->global->values.get (t))
+ if (*p != NULL_TREE)
+ {
+ r = *p;
+ break;
+ }
r = decl_constant_value (t, /*unshare_p=*/false);
if (TREE_CODE (r) == TARGET_EXPR
&& TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR)
@@ -1848,18 +1962,6 @@ eval_constant_expression (const constexpr_ctx *ctx, tree t, bool lval,
}
break;
- case VAR_DECL:
- if (DECL_HAS_VALUE_EXPR_P (t))
- {
- r = DECL_VALUE_EXPR (t);
- return eval_constant_expression (ctx, r, lval, non_constant_p,
- overflow_p);
- }
- else
- r = DECL_VALUE_EXPR (t);
- return eval_constant_expression (ctx, r, lval, non_constant_p,
- overflow_p);
-
case PARM_DECL:
if (lval && !TYPE_REF_P (TREE_TYPE (t)))
/* glvalue use. */;
@@ -1923,7 +2025,7 @@ eval_constant_expression (const constexpr_ctx *ctx, tree t, bool lval,
case LTGT_EXPR:
case RANGE_EXPR:
case COMPLEX_EXPR:
- r = eval_binary_expression (ctx, t, false, non_constant_p, overflow_p);
+ r = eval_binary_expression (ctx, t, lval, non_constant_p, overflow_p);
break;
/* fold can introduce non-IF versions of these; still treat them as
@@ -2004,15 +2106,14 @@ eval_constant_expression (const constexpr_ctx *ctx, tree t, bool lval,
break;
case CALL_EXPR:
- r = eval_call_expression (ctx, t, false, non_constant_p, overflow_p);
+ r = eval_call_expression (ctx, t, lval, non_constant_p, overflow_p);
break;
case RETURN_EXPR:
- rust_assert (TREE_OPERAND (t, 0) != NULL_TREE);
- r = eval_constant_expression (ctx, TREE_OPERAND (t, 0), false,
- non_constant_p, overflow_p);
- break;
-
+ if (TREE_OPERAND (t, 0) != NULL_TREE)
+ r = eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval,
+ non_constant_p, overflow_p);
+ /* FALLTHRU */
case BREAK_STMT:
case CONTINUE_STMT:
if (jump_target)
@@ -2085,9 +2186,9 @@ eval_constant_expression (const constexpr_ctx *ctx, tree t, bool lval,
break;
case STATEMENT_LIST:
- // new_ctx = *ctx;
- // new_ctx.ctor = new_ctx.object = NULL_TREE;
- return eval_statement_list (ctx, t, non_constant_p, overflow_p,
+ new_ctx = *ctx;
+ new_ctx.ctor = new_ctx.object = NULL_TREE;
+ return eval_statement_list (&new_ctx, t, non_constant_p, overflow_p,
jump_target);
case BIND_EXPR:
@@ -3365,8 +3466,7 @@ eval_call_expression (const constexpr_ctx *ctx, tree t, bool lval,
if (depth_ok && !non_constant_args && ctx->strict)
{
new_call.hash = constexpr_fundef_hasher::hash (new_call.fundef);
- // new_call.hash
- // = iterative_hash_template_arg (new_call.bindings, new_call.hash);
+ new_call.hash = iterative_hash_object (new_call.bindings, new_call.hash);
new_call.hash
= iterative_hash_object (ctx->manifestly_const_eval, new_call.hash);
@@ -4555,24 +4655,22 @@ eval_statement_list (const constexpr_ctx *ctx, tree t, bool *non_constant_p,
{
/* We've found a continue, so skip everything until we reach
the label its jumping to. */
- // FIXME
- // if (continues (jump_target))
- // {
- // if (label_matches (ctx, jump_target, stmt))
- // /* Found it. */
- // *jump_target = NULL_TREE;
- // else
- // continue;
- // }
+ if (continues (jump_target))
+ {
+ if (label_matches (ctx, jump_target, stmt))
+ /* Found it. */
+ *jump_target = NULL_TREE;
+ else
+ continue;
+ }
if (TREE_CODE (stmt) == DEBUG_BEGIN_STMT)
continue;
r = eval_constant_expression (ctx, stmt, false, non_constant_p,
overflow_p, jump_target);
if (*non_constant_p)
break;
- // FIXME
- // if (returns (jump_target) || breaks (jump_target))
- // break;
+ if (returns (jump_target) || breaks (jump_target))
+ break;
}
if (*jump_target && jump_target == &local_target)
{
@@ -4621,7 +4719,7 @@ eval_conditional_expression (const constexpr_ctx *ctx, tree t, bool lval,
val = TREE_OPERAND (t, 2);
else
val = TREE_OPERAND (t, 1);
- if (TREE_CODE (t) == IF_STMT && !val)
+ if (/*TREE_CODE (t) == IF_STMT && */ !val)
val = void_node;
return eval_constant_expression (ctx, val, lval, non_constant_p, overflow_p,
jump_target);
diff --git a/gcc/testsuite/rust/compile/const4.rs b/gcc/testsuite/rust/compile/const4.rs
new file mode 100644
index 00000000000..17beedefc30
--- /dev/null
+++ b/gcc/testsuite/rust/compile/const4.rs
@@ -0,0 +1,22 @@
+// { dg-options "-w -O0 -fdump-tree-gimple" }
+const A: i32 = 1;
+
+const fn test(a: i32) -> i32 {
+ let b = A + a;
+ if b == 2 {
+ return b + 2;
+ }
+ a
+}
+
+const B: i32 = test(1);
+const C: i32 = test(12);
+
+fn main() {
+ // { dg-final { scan-tree-dump-times {a = 1} 1 gimple } }
+ let a = A;
+ // { dg-final { scan-tree-dump-times {b = 4} 1 gimple } }
+ let b = B;
+ // { dg-final { scan-tree-dump-times {c = 12} 1 gimple } }
+ let c = C;
+}
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