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Differential D97648

[profile] Delete zero-size dummy sections
ClosedPublic

Authored by MaskRay on Feb 28 2021, 5:08 PM.

Details

Reviewers
davidxl
phosek
Commits
rGdc93b1127c5e: [profile] Delete zero-size dummy sections
Summary

They were added so that if no metadata section is present,
__start_llvm_prf_* references would not cause "undefined symbol"
errors. By switching to undefined weak symbols in D96936, the dummy
sections are not needed.

This patch is also needed to work around
https://sourceware.org/bugzilla/show_bug.cgi?id=27490

Diff Detail

Event Timeline

MaskRay requested review of this revision.Feb 28 2021, 5:08 PM
MaskRay created this revision.
Herald added a project: Restricted Project. · View Herald TranscriptFeb 28 2021, 5:08 PM
Herald added a subscriber: Restricted Project. · View Herald Transcript
Harbormaster completed remote builds in B91259: Diff 327007.Feb 28 2021, 5:37 PM
davidxl accepted this revision.Feb 28 2021, 6:25 PM

lgtm

This revision is now accepted and ready to land.Feb 28 2021, 6:25 PM
Closed by commit rGdc93b1127c5e: [profile] Delete zero-size dummy sections (authored by MaskRay). · Explain WhyFeb 28 2021, 9:07 PM
This revision was automatically updated to reflect the committed changes.
MaskRay added a commit: rGdc93b1127c5e: [profile] Delete zero-size dummy sections.
pirama mentioned this in D108486: [profile] Add back zero-sized dummy sections.Aug 20 2021, 2:20 PM

Revision Contents

PathSize
compiler-rt/
lib/
profile/
14 lines

Diff 327024

compiler-rt/lib/profile/InstrProfilingPlatformLinux.c

Show All 32 Lines
extern uint64_t PROF_CNTS_START COMPILER_RT_VISIBILITY COMPILER_RT_WEAK; extern uint64_t PROF_CNTS_START COMPILER_RT_VISIBILITY COMPILER_RT_WEAK;
extern uint64_t PROF_CNTS_STOP COMPILER_RT_VISIBILITY COMPILER_RT_WEAK; extern uint64_t PROF_CNTS_STOP COMPILER_RT_VISIBILITY COMPILER_RT_WEAK;
extern uint32_t PROF_ORDERFILE_START COMPILER_RT_VISIBILITY COMPILER_RT_WEAK; extern uint32_t PROF_ORDERFILE_START COMPILER_RT_VISIBILITY COMPILER_RT_WEAK;
extern char PROF_NAME_START COMPILER_RT_VISIBILITY COMPILER_RT_WEAK; extern char PROF_NAME_START COMPILER_RT_VISIBILITY COMPILER_RT_WEAK;
extern char PROF_NAME_STOP COMPILER_RT_VISIBILITY COMPILER_RT_WEAK; extern char PROF_NAME_STOP COMPILER_RT_VISIBILITY COMPILER_RT_WEAK;
extern ValueProfNode PROF_VNODES_START COMPILER_RT_VISIBILITY COMPILER_RT_WEAK; extern ValueProfNode PROF_VNODES_START COMPILER_RT_VISIBILITY COMPILER_RT_WEAK;
extern ValueProfNode PROF_VNODES_STOP COMPILER_RT_VISIBILITY COMPILER_RT_WEAK; extern ValueProfNode PROF_VNODES_STOP COMPILER_RT_VISIBILITY COMPILER_RT_WEAK;
/* Add dummy data to ensure the section is always created. Add used attribute so
* that they are linker GC roots on supported ELF platforms.
*/
__llvm_profile_data __prof_data_sect_data[0] COMPILER_RT_SECTION(
INSTR_PROF_DATA_SECT_NAME) COMPILER_RT_USED;
uint64_t __prof_cnts_sect_data[0] COMPILER_RT_SECTION(INSTR_PROF_CNTS_SECT_NAME)
COMPILER_RT_USED;
uint32_t __prof_orderfile_sect_data[0] COMPILER_RT_SECTION(
INSTR_PROF_ORDERFILE_SECT_NAME) COMPILER_RT_USED;
const char __prof_nms_sect_data[0] COMPILER_RT_SECTION(
INSTR_PROF_NAME_SECT_NAME) COMPILER_RT_USED;
ValueProfNode __prof_vnodes_sect_data[0] COMPILER_RT_SECTION(
INSTR_PROF_VNODES_SECT_NAME) COMPILER_RT_USED;
COMPILER_RT_VISIBILITY const __llvm_profile_data * COMPILER_RT_VISIBILITY const __llvm_profile_data *
__llvm_profile_begin_data(void) { __llvm_profile_begin_data(void) {
return &PROF_DATA_START; return &PROF_DATA_START;
} }
COMPILER_RT_VISIBILITY const __llvm_profile_data * COMPILER_RT_VISIBILITY const __llvm_profile_data *
__llvm_profile_end_data(void) { __llvm_profile_end_data(void) {
return &PROF_DATA_STOP; return &PROF_DATA_STOP;
} }
Show All 27 Lines