Let .llvm_bb_addr_map section use the same unique id as its associated .text section.

[rahmanl]

Summary

Currently, llvm_bb_addr_map sections are generated per section names because we use
the LinkedToSymbol argument of getELFSection. This will cause the address map tables of functions
grouped into the same section when -function-sections=true -unique-section-names=false which is not
the intended behaviour. This patch lets the unique id of every .text section propagate to the associated
.llvm_bb_addr_map section.

[rahmanl]

• Add comment.

[MaskRay]

llvm/test/CodeGen/X86/basic-block-sections-labels.ll

2–3

For FileCheck options, -- is more common.

58–61

Append {{$}} and try aligning the start of .section

60

What happens with the whitespace change?

71

Append {{$}} to show that ,unique is not used

[MaskRay]

Yes that .stack_sizes needs a similar fix. @grimar or I can fix it.

[tmsriram]

This LGTM.

[rahmanl]

• Add {{$}} to the checks.

[rahmanl]

• Add {{$}} to the checks.

[rahmanl]

Thank you for the comments @MaskRay . Are there any style guidelines for the test files? I wasn't able to find anything online.

[MaskRay]

In D92113#2423616, @rahmanl wrote:

Thank you for the comments @MaskRay . Are there any style guidelines for the test files? I wasn't able to find anything online.

Thanks for the update. There is no official style guideline. I just improved my way adding tests by learning from others who are nitpicking (commendatory term here!) on tests.
I requested {{$}} because the section directive may have ,unique,N suffixes and without {{$}} you could not check that no ,unique,N occurred.

[rahmanl]

rebase.

llvm/lib/MC/MCObjectFileInfo.cpp

MCObjectFileInfo::getBBAddrMapSection(const MCSection &TextSec) const {
   const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
   unsigned Flags = ELF::SHF_LINK_ORDER;
   StringRef GroupName;
   if (const MCSymbol *Group = ElfSec.getGroup()) {
     GroupName = Group->getName();
     Flags |= ELF::SHF_GROUP;
   }
 
+  // Use the text section's begin symbol and unique ID to create a separate
+  // .llvm_bb_addr_map section associated with every unique text section.
   return Ctx->getELFSection(".llvm_bb_addr_map", ELF::SHT_LLVM_BB_ADDR_MAP,
-                            Flags, 0, GroupName, MCSection::NonUniqueID,
+                            Flags, 0, GroupName, ElfSec.getUniqueID(),
                             cast<MCSymbolELF>(TextSec.getBeginSymbol()));
 }

llvm/test/CodeGen/X86/basic-block-sections-labels.ll

 ; Check the basic block sections labels option
-; RUN: llc < %s -mtriple=x86_64 -function-sections -basic-block-sections=labels | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64 -function-sections -unique-section-names=true -basic-block-sections=labels | FileCheck %s --check-prefix=UNIQ
+; RUN: llc < %s -mtriple=x86_64 -function-sections -unique-section-names=false -basic-block-sections=labels | FileCheck %s --check-prefix=NOUNIQ
 
 define void @_Z3bazb(i1 zeroext) personality i32 (...)* @__gxx_personality_v0 {
   br i1 %0, label %2, label %7
 
 2:
   %3 = invoke i32 @_Z3barv()
           to label %7 unwind label %5
   br label %9

 }
 
 declare i32 @_Z3barv() #1
 
 declare i32 @_Z3foov() #1
 
 declare i32 @__gxx_personality_v0(...)
 
+; UNIQ:     .section .text._Z3bazb,"ax",@progbits{{$}}
+; NOUNIQ:   .section .text,"ax",@progbits,unique,1
 ; CHECK-LABEL:  _Z3bazb:
-; CHECK-LABEL:  .Lfunc_begin0:
-; CHECK-LABEL:  .LBB_END0_0:
-; CHECK-LABEL:  .LBB0_1:
-; CHECK-LABEL:  .LBB_END0_1:
-; CHECK-LABEL:  .LBB0_2:
-; CHECK-LABEL:  .LBB_END0_2:
-; CHECK-LABEL:  .LBB0_3:
-; CHECK-LABEL:  .LBB_END0_3:
-; CHECK-LABEL:  .Lfunc_end0:
+; CHECK-LABEL:  .Lfunc_begin0:
+; CHECK-LABEL:  .LBB_END0_0:
+; CHECK-LABEL:  .LBB0_1:
+; CHECK-LABEL:  .LBB_END0_1:
+; CHECK-LABEL:  .LBB0_2:
+; CHECK-LABEL:  .LBB_END0_2:
+; CHECK-LABEL:  .LBB0_3:
+; CHECK-LABEL:  .LBB_END0_3:
+; CHECK-LABEL:  .Lfunc_end0:
 
-; CHECK:  .section  .llvm_bb_addr_map,"o",@llvm_bb_addr_map,.text
+; UNIQ:     .section  .llvm_bb_addr_map,"o",@llvm_bb_addr_map,.text._Z3bazb{{$}}
+;; Verify that with -unique-section-names=false, the unique id of the text section gets assigned to the llvm_bb_addr_map section.
+; NOUNIQ:   .section  .llvm_bb_addr_map,"o",@llvm_bb_addr_map,.text,unique,1
 ; CHECK-NEXT: .quad .Lfunc_begin0
 ; CHECK-NEXT: .byte 4
 ; CHECK-NEXT: .uleb128 .Lfunc_begin0-.Lfunc_begin0
 ; CHECK-NEXT: .uleb128 .LBB_END0_0-.Lfunc_begin0
 ; CHECK-NEXT: .byte 0
 ; CHECK-NEXT: .uleb128 .LBB0_1-.Lfunc_begin0
 ; CHECK-NEXT: .uleb128 .LBB_END0_1-.LBB0_1
 ; CHECK-NEXT: .byte 0
 ; CHECK-NEXT: .uleb128 .LBB0_2-.Lfunc_begin0
 ; CHECK-NEXT: .uleb128 .LBB_END0_2-.LBB0_2
-; CHECK-NEXT: .byte 1
-; CHECK-NEXT: .uleb128 .LBB0_3-.Lfunc_begin0
-; CHECK-NEXT: .uleb128 .LBB_END0_3-.LBB0_3
-; CHECK-NEXT: .byte 5
+; CHECK-NEXT:   .byte 1
+; CHECK-NEXT:   .uleb128 .LBB0_3-.Lfunc_begin0
+; CHECK-NEXT:   .uleb128 .LBB_END0_3-.LBB0_3
+; CHECK-NEXT:   .byte 5