[PATCH] D97336: [InstrProfiling] Use nobits for __llvm_prf_cnts with binutils >=2.28

[Petr Hosek via Phabricator via llvm-commits]

phosek updated this revision to Diff 325908.
phosek added a comment.

Updated test and extra comment.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D97336/new/

https://reviews.llvm.org/D97336

Files:
  llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
  llvm/test/Instrumentation/InstrProfiling/X86/nobits.ll


Index: llvm/test/Instrumentation/InstrProfiling/X86/nobits.ll
===================================================================
--- llvm/test/Instrumentation/InstrProfiling/X86/nobits.ll
+++ llvm/test/Instrumentation/InstrProfiling/X86/nobits.ll
@@ -1,5 +1,6 @@
 ;; Ensure that SHT_NOBITS section type is set for __llvm_prf_cnts in ELF.
-; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -binutils-version=2.27 | FileCheck %s --check-prefix=OLD
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -binutils-version=2.28 | FileCheck %s --check-prefix=NEW
 
 @__profc_foo = hidden global [1 x i64] zeroinitializer, section "__llvm_prf_cnts", align 8
 
@@ -12,4 +13,5 @@
 
 declare void @llvm.instrprof.increment(i8*, i64, i32, i32)
 
-; CHECK: .section __llvm_prf_cnts,"aw", at nobits
+; OLD: .section __llvm_prf_cnts,"aw", at progbits
+; NEW: .section __llvm_prf_cnts,"aw", at nobits
Index: llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
===================================================================
--- llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -425,7 +425,8 @@
                                                            MMI, Streamer);
 }
 
-static SectionKind getELFKindForNamedSection(StringRef Name, SectionKind K) {
+static SectionKind getELFKindForNamedSection(MCContext &Ctx, StringRef Name,
+                                             SectionKind K) {
   // N.B.: The defaults used in here are not the same ones used in MC.
   // We follow gcc, MC follows gas. For example, given ".section .eh_frame",
   // both gas and MC will produce a section with no flags. Given
@@ -440,8 +441,11 @@
       Name == ".llvmbc" || Name == ".llvmcmd")
     return SectionKind::getMetadata();
 
+  // GNU binutils ld.bfd <2.28 has a bug which causes __start_/__stop_ symbols
+  // for SHT_NOBITS sections to have incorrect address
   if (Name == getInstrProfSectionName(IPSK_cnts, Triple::ELF,
-                                      /*AddSegmentInfo=*/false))
+                                      /*AddSegmentInfo=*/false) &&
+      Ctx.getAsmInfo()->binutilsIsAtLeast(2, 28))
     return SectionKind::getBSS();
 
   if (Name.empty() || Name[0] != '.') return K;
@@ -674,7 +678,7 @@
   }
 
   // Infer section flags from the section name if we can.
-  Kind = getELFKindForNamedSection(SectionName, Kind);
+  Kind = getELFKindForNamedSection(getContext(), SectionName, Kind);
 
   StringRef Group = "";
   bool IsComdat = false;


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