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* [PATCH, rs6000] Add non-relative jump table support for 64bit rs6000
@ 2020-07-30  5:21 HAO CHEN GUI
  2020-07-30  8:35 ` David Edelsohn
  0 siblings, 1 reply; 7+ messages in thread
From: HAO CHEN GUI @ 2020-07-30  5:21 UTC (permalink / raw)
  To: dje.gcc; +Cc: gcc-patches, segher@kernel.crashing.org wschmidt

David,

Seems there is something wrong with my email box.  I lost your email. I 
reconfigured the box and it should be OK now.

Could you inform me how to exclude AIX from the condition testing? By 
the ABI? Thanks a lot.

Haochen Gui


^ permalink raw reply	[flat|nested] 7+ messages in thread
* [PATCH, rs6000] Add non-relative jump table support for 64bit rs6000
@ 2020-07-28  5:25 HAO CHEN GUI
  2020-07-28  9:12 ` Kewen.Lin
  2020-07-30 23:42 ` Segher Boessenkool
  0 siblings, 2 replies; 7+ messages in thread
From: HAO CHEN GUI @ 2020-07-28  5:25 UTC (permalink / raw)
  To: gcc-patches; +Cc: segher.boessenkool

[-- Attachment #1: Type: text/plain, Size: 1110 bytes --]

Hi,

This patch adds non-relative jump table support for 64bit rs6000. It 
implements ASM_OUTPUT_ADDR_VEC_ELT and corresponding expansion of jump 
table instruction for 64bit rs6000. We want to put non-relative jump 
table in data.rel.ro section for rs6000. So I add a new target hook - 
TARGET_ASM_SELECT_JUMPTABLE_SECTION to choose which section jump table 
should be put in. It puts the jump table in data.rel.ro for 64bit 
rs6000. For other platforms, it calls 
targetm.asm_out.function_rodata_section, just as before. We want to have 
an option to use non-relative jump table even when PIC flag is set. So I 
add a new option - "mforce-nonrelative-jumptables" for rs6000.  It 
enables the feature by default. The option takes effect in target hook - 
TARGET_ASM_GENERATE_PIC_ADDR_DIFF_VEC.

static bool
rs6000_gen_pic_addr_diff_vec (void)
{
   return TARGET_32BIT || !rs6000_force_nonrelative_jumptables;
}

The attachments are the patch diff file and change log file.

Bootstrapped and tested on powerpc64le-linux-gnu with no regressions.  
Is this okay for trunk? Any recommendations? Thanks a lot.


[-- Attachment #2: ChangeLog --]
[-- Type: text/plain, Size: 1040 bytes --]

2019-11-30  Haochen Gui  <guihaoc@gcc.gnu.org>

        * config/rs6000/linux64.h (JUMP_TABLES_IN_TEXT_SECTION): Redefine.
        * config/rs6000/rs6000.c (TARGET_ASM_GENERATE_PIC_ADDR_DIFF_VEC,TARGET_ASM_SELECT_JUMPTABLE_SECTION): Implement two hooks.
		* config/rs6000/rs6000.h (CASE_VECTOR_PC_RELATIVE,CASE_VECTOR_MODE) Redefine.
		* config/rs6000/rs6000.md (nonrelative_tablejumpdi, nonrelative_tablejumpdi_nospec) Add two expansions.
		* config/rs6000/rs6000.opt (mforce-nonrelative-jumptables) Add a new options for rs6000.
        * doc/tm.texi.in (TARGET_ASM_SELECT_JUMPTABLE_SECTION): Likewise.
        * doc/tm.texi: Regenerate.
        * final.c (targetm.asm_out.select_jumptable_section): Replace targetm.asm_out.function_rodata_section with targetm.asm_out.select_jumptable_section in jumptable section selection.
        * output.h (default_select_jumptable_section): Declare.
        * target.def (default_select_jumptable_section): Likewise
        * varasm.c (default_select_jumptable_section): Implementation.

[-- Attachment #3: patch.diff --]
[-- Type: text/plain, Size: 11649 bytes --]

diff --git a/gcc/config/rs6000/linux64.h b/gcc/config/rs6000/linux64.h
index 34776c8421e..e9a1fed43cd 100644
--- a/gcc/config/rs6000/linux64.h
+++ b/gcc/config/rs6000/linux64.h
@@ -324,7 +324,7 @@ extern int dot_symbols;
 
 /* Indicate that jump tables go in the text section.  */
 #undef  JUMP_TABLES_IN_TEXT_SECTION
-#define JUMP_TABLES_IN_TEXT_SECTION TARGET_64BIT
+#define JUMP_TABLES_IN_TEXT_SECTION (TARGET_64BIT && flag_pic && !rs6000_force_nonrelative_jumptables)
 
 /* The linux ppc64 ABI isn't explicit on whether aggregates smaller
    than a doubleword should be padded upward or downward.  You could
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 58f5d780603..d0c0ac6529a 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -1369,6 +1369,12 @@ static const struct attribute_spec rs6000_attribute_table[] =
 #undef TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA
 #define TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA rs6000_output_addr_const_extra
 
+#undef  TARGET_ASM_GENERATE_PIC_ADDR_DIFF_VEC
+#define TARGET_ASM_GENERATE_PIC_ADDR_DIFF_VEC rs6000_gen_pic_addr_dif_vec
+
+#undef TARGET_ASM_SELECT_JUMPTABLE_SECTION
+#define TARGET_ASM_SELECT_JUMPTABLE_SECTION rs6000_select_jumptable_section
+
 #undef TARGET_LEGITIMIZE_ADDRESS
 #define TARGET_LEGITIMIZE_ADDRESS rs6000_legitimize_address
 
@@ -26494,6 +26500,68 @@ rs6000_cannot_substitute_mem_equiv_p (rtx mem)
   return false;
 }
 
+/* Implement TARGET_ASM_GENERATE_PIC_ADDR_DIFF_VEC. Return false if rs6000_force_nonrelative_jumptables is set and target is 64bit. */
+
+static bool
+rs6000_gen_pic_addr_dif_vec (void)
+{
+  return !rs6000_force_nonrelative_jumptables;
+}
+
+/* Implement TARGET_ASM_FUNCTION_RODATA_SECTION. Put non-relative jump table in data.rel.ro section */
+
+section *
+rs6000_select_jumptable_section (tree decl)
+{
+  if (TARGET_32BIT)
+    return default_function_rodata_section (decl);
+
+  if (decl != NULL_TREE && DECL_SECTION_NAME (decl))
+    {
+      const char *name = DECL_SECTION_NAME (decl);
+
+      if (DECL_COMDAT_GROUP (decl) && HAVE_COMDAT_GROUP)
+        {
+          const char *dot;
+          size_t len;
+          char* rname;
+
+          dot = strchr (name + 1, '.');
+          if (!dot)
+            dot = name;
+          len = strlen (dot) + 13;
+          rname = (char *) alloca (len);
+
+          strcpy (rname, ".data.rel.ro");
+          strcat (rname, dot);
+          return get_section (rname, SECTION_WRITE | SECTION_RELRO | SECTION_LINKONCE, decl);
+        }
+        /* For .gnu.linkonce.t.foo we want to use .gnu.linkonce.r.foo.  */
+         else if (DECL_COMDAT_GROUP (decl)
+               && strncmp (name, ".gnu.linkonce.t.", 16) == 0)
+        {
+          size_t len = strlen (name) + 1;
+          char *rname = (char *) alloca (len);
+
+          memcpy (rname, name, len);
+          rname[14] = 'r';
+          return get_section (rname, SECTION_LINKONCE, decl);
+        }
+        /* For .text.foo we want to use .data.rel.ro.foo.  */
+         else if (flag_function_sections && flag_data_sections
+              && strncmp (name, ".text.", 6) == 0)
+        {
+          size_t len = strlen (name) + 1;
+          char *rname = (char *) alloca (len + 7);
+
+          memcpy (rname, ".data.rel.ro", 12);
+          memcpy (rname + 12, name + 5, len - 5);
+          return get_section (rname, SECTION_WRITE | SECTION_RELRO, decl);
+        }
+    }
+  return get_section (".data.rel.ro", SECTION_WRITE | SECTION_RELRO, decl);
+}
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 #include "gt-rs6000.h"
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index 1209a33173e..2a148aff9e4 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -1752,15 +1752,15 @@ typedef struct rs6000_args
 
 /* #define LEGITIMATE_PIC_OPERAND_P (X) */
 \f
-/* Specify the machine mode that this machine uses
-   for the index in the tablejump instruction.  */
-#define CASE_VECTOR_MODE SImode
-
 /* Define as C expression which evaluates to nonzero if the tablejump
    instruction expects the table to contain offsets from the address of the
    table.
    Do not define this if the table should contain absolute addresses.  */
-#define CASE_VECTOR_PC_RELATIVE 1
+#define CASE_VECTOR_PC_RELATIVE TARGET_32BIT
+
+/* Specify the machine mode that this machine uses
+   for the index in the tablejump instruction.  */
+#define CASE_VECTOR_MODE (TARGET_32BIT || (flag_pic && !rs6000_force_nonrelative_jumptables) ? SImode : DImode)
 
 /* Define this as 1 if `char' should by default be signed; else as 0.  */
 #define DEFAULT_SIGNED_CHAR 0
@@ -2190,6 +2190,15 @@ extern char rs6000_reg_names[][8];	/* register names (0 vs. %r0).  */
        putc ('\n', FILE);				\
      } while (0)
 
+/* This is how to output an element of a case-vector that is non-relative. */
+#define ASM_OUTPUT_ADDR_VEC_ELT(FILE, VALUE) \
+  do { char buf[100];                                   \
+       fputs ("\t.quad ", FILE);                        \
+       ASM_GENERATE_INTERNAL_LABEL (buf, "L", VALUE);   \
+       assemble_name (FILE, buf);                       \
+       putc ('\n', FILE);                              \
+     } while (0)
+
 /* This is how to output an assembler line
    that says to advance the location counter
    to a multiple of 2**LOG bytes.  */
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 0aa5265d199..76b9f185e88 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -12670,8 +12670,10 @@
     {
       if (TARGET_32BIT)
       	emit_jump_insn (gen_tablejumpsi (operands[0], operands[1]));
-      else
+      else if (flag_pic && !rs6000_force_nonrelative_jumptables)
 	emit_jump_insn (gen_tablejumpdi (operands[0], operands[1]));
+      else 
+        emit_jump_insn (gen_nonrelative_tablejumpdi (operands[0], operands[1]));
     }
   else
     {
@@ -12679,8 +12681,10 @@
       rtx jump;
       if (TARGET_32BIT)
 	jump = gen_tablejumpsi_nospec (operands[0], operands[1], ccreg);
-      else
+      else if (flag_pic && !rs6000_force_nonrelative_jumptables)
 	jump = gen_tablejumpdi_nospec (operands[0], operands[1], ccreg);
+      else
+	jump = gen_nonrelative_tablejumpdi_nospec (operands[0], operands[1], ccreg);
       emit_jump_insn (jump);
     }
   DONE;
@@ -12731,6 +12735,17 @@
   operands[4] = gen_reg_rtx (DImode);
 })
 
+(define_expand "nonrelative_tablejumpdi"
+  [(set (match_dup 2)
+        (match_operand:DI 0 "gpc_reg_operand" "r"))
+   (parallel [(set (pc)
+                   (match_dup 2))
+              (use (label_ref (match_operand 1)))])]
+   "TARGET_64BIT && rs6000_speculate_indirect_jumps"
+ {
+  operands[2] = gen_reg_rtx (DImode);
+ })
+
 (define_expand "tablejumpdi_nospec"
   [(set (match_dup 5)
         (sign_extend:DI (match_operand:SI 0 "lwa_operand")))
@@ -12748,6 +12763,19 @@
   operands[5] = gen_reg_rtx (DImode);
 })
 
+(define_expand "nonrelative_tablejumpdi_nospec"
+  [(set (match_dup 3)
+        (match_operand:SI 0 "gpc_reg_operand" "r"))
+   (parallel [(set (pc)
+                   (match_dup 3))
+              (use (label_ref (match_operand 1)))
+              (clobber (match_operand 2))])]
+  "TARGET_64BIT && !rs6000_speculate_indirect_jumps"
+{
+  operands[3] = gen_reg_rtx (DImode);
+})
+
+
 (define_insn "*tablejump<mode>_internal1"
   [(set (pc)
 	(match_operand:P 0 "register_operand" "c,*l"))
diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
index f95b8279270..b3f69a73053 100644
--- a/gcc/config/rs6000/rs6000.opt
+++ b/gcc/config/rs6000/rs6000.opt
@@ -578,3 +578,6 @@ Generate (do not generate) prefixed memory instructions.
 mpcrel
 Target Report Mask(PCREL) Var(rs6000_isa_flags)
 Generate (do not generate) pc-relative memory addressing.
+
+mforce-nonrelative-jumptables
+Target Undocumented Var(rs6000_force_nonrelative_jumptables) Init(1) Save
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 6e7d9dc54a9..28e2afabe7e 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -7712,6 +7712,12 @@ if function is in @code{.text.name}, and the normal readonly-data section
 otherwise.
 @end deftypefn
 
+@deftypefn {Target Hook} {section *} TARGET_ASM_SELECT_JUMPTABLE_SECTION (tree @var{decl})
+Return the section of jump table associated with
+@samp{DECL_SECTION_NAME (@var{decl})}.
+The default version of this function selects the rodata section.
+@end deftypefn
+
 @deftypevr {Target Hook} {const char *} TARGET_ASM_MERGEABLE_RODATA_PREFIX
 Usually, the compiler uses the prefix @code{".rodata"} to construct
 section names for mergeable constant data.  Define this macro to override
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index 3be984bbd5c..173a8dfaee8 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -5007,6 +5007,8 @@ it is unlikely to be called.
 
 @hook TARGET_ASM_FUNCTION_RODATA_SECTION
 
+@hook TARGET_ASM_SELECT_JUMPTABLE_SECTION
+
 @hook TARGET_ASM_MERGEABLE_RODATA_PREFIX
 
 @hook TARGET_ASM_TM_CLONE_TABLE_SECTION
diff --git a/gcc/final.c b/gcc/final.c
index a3601964a8d..18ed1f6788c 100644
--- a/gcc/final.c
+++ b/gcc/final.c
@@ -2492,7 +2492,7 @@ final_scan_insn_1 (rtx_insn *insn, FILE *file, int optimize_p ATTRIBUTE_UNUSED,
 	    {
 	      int log_align;
 
-	      switch_to_section (targetm.asm_out.function_rodata_section
+	      switch_to_section (targetm.asm_out.select_jumptable_section
 				 (current_function_decl));
 
 #ifdef ADDR_VEC_ALIGN
@@ -2571,7 +2571,7 @@ final_scan_insn_1 (rtx_insn *insn, FILE *file, int optimize_p ATTRIBUTE_UNUSED,
 #endif
 
 	    if (! JUMP_TABLES_IN_TEXT_SECTION)
-	      switch_to_section (targetm.asm_out.function_rodata_section
+	      switch_to_section (targetm.asm_out.select_jumptable_section
 				 (current_function_decl));
 	    else
 	      switch_to_section (current_function_section ());
diff --git a/gcc/output.h b/gcc/output.h
index eb253c50329..b01228b224c 100644
--- a/gcc/output.h
+++ b/gcc/output.h
@@ -573,6 +573,7 @@ extern section *default_elf_select_section (tree, int, unsigned HOST_WIDE_INT);
 extern void default_unique_section (tree, int);
 extern section *default_function_rodata_section (tree);
 extern section *default_no_function_rodata_section (tree);
+extern section *default_select_jumptable_section (tree);
 extern section *default_clone_table_section (void);
 extern section *default_select_rtx_section (machine_mode, rtx,
 					    unsigned HOST_WIDE_INT);
diff --git a/gcc/target.def b/gcc/target.def
index 07059a87caf..32a8523ae16 100644
--- a/gcc/target.def
+++ b/gcc/target.def
@@ -561,6 +561,15 @@ otherwise.",
  section *, (tree decl),
  default_function_rodata_section)
 
+/* Return the section of jump table associated with function DECL.  */
+DEFHOOK
+(select_jumptable_section,
+ "Return the section of jump table associated with\n\
+@samp{DECL_SECTION_NAME (@var{decl})}.\n\
+The default version of this function selects the rodata section.",
+ section *, (tree decl),
+ default_select_jumptable_section)
+
 /* Nonnull if the target wants to override the default ".rodata" prefix
    for mergeable data sections.  */
 DEFHOOKPOD
diff --git a/gcc/varasm.c b/gcc/varasm.c
index 4070f9c17e8..8cdcfbca4f5 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -788,6 +788,14 @@ default_no_function_rodata_section (tree decl ATTRIBUTE_UNUSED)
   return readonly_data_section;
 }
 
+/* Return target hook function_rotdata_section by default.  */
+
+section *
+default_select_jumptable_section (tree decl)
+{
+  return targetm.asm_out.function_rodata_section(decl);
+}
+
 /* A subroutine of mergeable_string_section and mergeable_constant_section.  */
 
 static const char *

^ permalink raw reply	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-07-30 23:42 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-30  5:21 [PATCH, rs6000] Add non-relative jump table support for 64bit rs6000 HAO CHEN GUI
2020-07-30  8:35 ` David Edelsohn
2020-07-30 22:40   ` Segher Boessenkool
  -- strict thread matches above, loose matches on Subject: below --
2020-07-28  5:25 HAO CHEN GUI
2020-07-28  9:12 ` Kewen.Lin
2020-07-28 16:56   ` David Edelsohn
2020-07-30 23:42 ` Segher Boessenkool

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