[llvm] e0bf234 - Let .llvm_bb_addr_map section use the same unique id as its associated .text section.

[Rahman Lavaee via llvm-commits]

Author: Rahman Lavaee
Date: 2020-12-01T09:21:00-08:00
New Revision: e0bf2349303f6b40e3ddd5377ea08a5c0867ece4

URL: https://github.com/llvm/llvm-project/commit/e0bf2349303f6b40e3ddd5377ea08a5c0867ece4
DIFF: https://github.com/llvm/llvm-project/commit/e0bf2349303f6b40e3ddd5377ea08a5c0867ece4.diff

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

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.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D92113

Added: 
    

Modified: 
    llvm/lib/MC/MCObjectFileInfo.cpp
    llvm/test/CodeGen/X86/basic-block-sections-labels.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index 75e65e3f10f47..fbc7cf1efcdb6 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -1014,7 +1014,9 @@ MCObjectFileInfo::getBBAddrMapSection(const MCSection &TextSec) const {
     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()));
 }

diff  --git a/llvm/test/CodeGen/X86/basic-block-sections-labels.ll b/llvm/test/CodeGen/X86/basic-block-sections-labels.ll
index 026667bc32c7e..8a76fef672eb1 100644
--- a/llvm/test/CodeGen/X86/basic-block-sections-labels.ll
+++ b/llvm/test/CodeGen/X86/basic-block-sections-labels.ll
@@ -1,5 +1,6 @@
 ; 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
@@ -28,6 +29,8 @@ declare i32 @_Z3foov() #1
 
 declare i32 @__gxx_personality_v0(...)
 
+; UNIQ:			.section .text._Z3bazb,"ax", at progbits{{$}}
+; NOUNIQ:		.section .text,"ax", at progbits,unique,1
 ; CHECK-LABEL:	_Z3bazb:
 ; CHECK-LABEL:	.Lfunc_begin0:
 ; CHECK-LABEL:	.LBB_END0_0:
@@ -39,7 +42,9 @@ declare i32 @__gxx_personality_v0(...)
 ; CHECK-LABEL:	.LBB_END0_3:
 ; CHECK-LABEL:	.Lfunc_end0:
 
-; CHECK:	.section	.llvm_bb_addr_map,"o", at llvm_bb_addr_map,.text
+; UNIQ:			.section	.llvm_bb_addr_map,"o", at 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", at llvm_bb_addr_map,.text,unique,1
 ; CHECK-NEXT:	.quad	.Lfunc_begin0
 ; CHECK-NEXT:	.byte	4
 ; CHECK-NEXT:	.uleb128 .Lfunc_begin0-.Lfunc_begin0