[PATCH] D97585: [InstrProfiling] Use llvm.compiler.used instead of llvm.used for ELF

[Fangrui Song via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGbf176c49e842: [InstrProfiling] Use llvm.compiler.used instead of llvm.used for ELF (authored by MaskRay).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D97585/new/

https://reviews.llvm.org/D97585

Files:
  llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
  llvm/test/Instrumentation/InstrProfiling/profiling.ll


Index: llvm/test/Instrumentation/InstrProfiling/profiling.ll
===================================================================
--- llvm/test/Instrumentation/InstrProfiling/profiling.ll
+++ llvm/test/Instrumentation/InstrProfiling/profiling.ll
@@ -1,7 +1,8 @@
-; RUN: opt < %s -instrprof -S | FileCheck %s
-; RUN: opt < %s -passes=instrprof -S | FileCheck %s
+; RUN: opt < %s -mtriple=x86_64 -passes=instrprof -S | FileCheck %s --check-prefixes=CHECK,ELF
+; RUN: opt < %s -mtriple=x86_64-apple-macosx10.10.0 -passes=instrprof -S | FileCheck %s --check-prefixes=CHECK,MACHO
+; RUN: opt < %s -mtriple=x86_64-windows -passes=instrprof -S | FileCheck %s --check-prefixes=CHECK,WIN
 
-target triple = "x86_64-apple-macosx10.10.0"
+; RUN: opt < %s -mtriple=x86_64-apple-macosx10.10.0 -instrprof -S | FileCheck %s
 
 ; CHECK: @__llvm_profile_runtime = external global i32
 
@@ -12,22 +13,34 @@
 @__profn_baz = hidden constant [3 x i8] c"baz"
 ; CHECK-NOT: __profn_baz
 
-; CHECK: @__profc_foo = hidden global [1 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
-; CHECK: @__profd_foo = hidden {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
+; ELF:   @__profc_foo = hidden global [1 x i64] zeroinitializer, section "__llvm_prf_cnts", comdat($__profd_foo), align 8
+; ELF:   @__profd_foo = hidden {{.*}}, section "__llvm_prf_data", comdat, align 8
+; MACHO: @__profc_foo = hidden global [1 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
+; MACHO: @__profd_foo = hidden {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
+; WIN:   @__profc_foo = internal global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
+; WIN:   @__profd_foo = internal {{.*}}, section ".lprfd$M", align 8
 define void @foo() {
   call void @llvm.instrprof.increment(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @__profn_foo, i32 0, i32 0), i64 0, i32 1, i32 0)
   ret void
 }
 
-; CHECK: @__profc_bar = hidden global [1 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
-; CHECK: @__profd_bar = hidden {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
+; ELF:   @__profc_bar = hidden global [1 x i64] zeroinitializer, section "__llvm_prf_cnts", comdat($__profd_bar), align 8
+; ELF:   @__profd_bar = hidden {{.*}}, section "__llvm_prf_data", comdat, align 8
+; MACHO: @__profc_bar = hidden global [1 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
+; MACHO: @__profd_bar = hidden {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
+; WIN:   @__profc_bar = internal global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
+; WIN:   @__profd_bar = internal {{.*}}, section ".lprfd$M", align 8
 define void @bar() {
   call void @llvm.instrprof.increment(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @__profn_bar, i32 0, i32 0), i64 0, i32 1, i32 0)
   ret void
 }
 
-; CHECK: @__profc_baz = hidden global [3 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
-; CHECK: @__profd_baz = hidden {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
+; ELF:   @__profc_baz = hidden global [3 x i64] zeroinitializer, section "__llvm_prf_cnts", comdat($__profd_baz), align 8
+; ELF:   @__profd_baz = hidden {{.*}}, section "__llvm_prf_data", comdat, align 8
+; MACHO: @__profc_baz = hidden global [3 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
+; MACHO: @__profd_baz = hidden {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
+; WIN:   @__profc_baz = internal global [3 x i64] zeroinitializer, section ".lprfc$M", align 8
+; WIN:   @__profd_baz = internal {{.*}}, section ".lprfd$M", align 8
 define void @baz() {
   call void @llvm.instrprof.increment(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @__profn_baz, i32 0, i32 0), i64 0, i32 3, i32 0)
   call void @llvm.instrprof.increment(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @__profn_baz, i32 0, i32 0), i64 0, i32 3, i32 1)
@@ -37,4 +50,6 @@
 
 declare void @llvm.instrprof.increment(i8*, i64, i32, i32)
 
-; CHECK: @llvm.used = appending global {{.*}} @__profd_foo {{.*}} @__profd_bar {{.*}} @__profd_baz {{.*}} section "llvm.metadata"
+; ELF:   @llvm.compiler.used = appending global {{.*}} @__llvm_profile_runtime_user {{.*}} @__profd_foo {{.*}} @__profd_bar {{.*}} @__profd_baz
+; MACHO: @llvm.used = appending global {{.*}} @__llvm_profile_runtime_user {{.*}} @__profd_foo {{.*}} @__profd_bar {{.*}} @__profd_baz
+; WIN:   @llvm.used = appending global {{.*}} @__llvm_profile_runtime_user {{.*}} @__profd_foo {{.*}} @__profd_bar {{.*}} @__profd_baz
Index: llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -1086,7 +1086,16 @@
 }
 
 void InstrProfiling::emitUses() {
-  if (!UsedVars.empty())
+  // The metadata sections are parallel arrays. Optimizers (e.g.
+  // GlobalOpt/ConstantMerge) may not discard associated sections as a unit, so
+  // we conservatively retain all unconditionally in the compiler.
+  //
+  // On ELF, the linker can guarantee the associated sections will be retained
+  // or discarded as a unit, so llvm.compiler.used is sufficient. Otherwise,
+  // conservatively make all of them retained by the linker.
+  if (TT.isOSBinFormatELF())
+    appendToCompilerUsed(*M, UsedVars);
+  else
     appendToUsed(*M, UsedVars);
 }
 


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