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[google] Emit relative addresses to function patch sections instead of absolute addresses. (issue6572065)
- From: harshit at google dot com (Harshit Chopra)
- To: reply at codereview dot appspotmail dot com,ppluzhnikov at google dot com,gcc-patches at gcc dot gnu dot org
- Date: Fri, 28 Sep 2012 02:24:37 -0700 (PDT)
- Subject: [google] Emit relative addresses to function patch sections instead of absolute addresses. (issue6572065)
commit fc3a55ccec9bc770c79f8a221f5abd397befc8f6
Author: Harshit Chopra <harshit@google.com>
Date: Thu Sep 20 17:49:59 2012 -0700
Instead of emitting absolute addresses to the function patch sections, emit relative addresses. Absolute addresses might require relocation, which is time consuming and fraught with other issues.
M gcc/config/i386/i386.c
Tested:
Ran make check-gcc and manually confirmed that the affected tests pass.
ChangeLog:
2012-09-28 Harshit Chopra <harshit@google.com>
* gcc/config/i386/i386.c (ix86_output_function_nops_prologue_epilogue): Emit relative address to function patch sections.
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index f72b0b5..8c9334f 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -11098,7 +11098,7 @@ ix86_output_function_nops_prologue_epilogue (FILE *file,
$LFPEL0:
<pre_instruction>
0x90 (repeated num_actual_nops times)
- .quad $LFPESL0
+ .quad $LFPESL0 - .
followed by section 'section_name' which contains the address
of instruction at 'label'.
*/
@@ -11110,7 +11110,10 @@ ix86_output_function_nops_prologue_epilogue (FILE *file,
asm_fprintf (file, ASM_BYTE"0x90\n");
fprintf (file, ASM_QUAD);
+ /* Output "section_label - ." for the relative address of the entry in
+ the section 'section_name'. */
assemble_name_raw (file, section_label);
+ fprintf (file, " - .");
fprintf (file, "\n");
/* Emit the backpointer section. For functions belonging to comdat group,
@@ -11144,7 +11147,7 @@ ix86_output_function_nops_prologue_epilogue (FILE *file,
.quad $LFPEL0
*/
ASM_OUTPUT_INTERNAL_LABEL (file, section_label);
- fprintf(file, ASM_QUAD"\t");
+ fprintf(file, ASM_QUAD);
assemble_name_raw (file, label);
fprintf (file, "\n");
--
This patch is available for review at http://codereview.appspot.com/6572065