[MemProf] Update the DISubprogram linkageName for clones (#145385)

This corrects the debug information for the cloned functions so that it
contains the correct linkage name.

Author: teresajohnson

llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp

@@ -4001,6 +4001,9 @@ ModuleCallsiteContextGraph::cloneFunctionForCallsite(
   std::string Name = getMemProfFuncName(Func.func()->getName(), CloneNo);
   assert(!Func.func()->getParent()->getFunction(Name));
   NewFunc->setName(Name);
+  if (auto *SP = NewFunc->getSubprogram())
+    SP->replaceLinkageName(
+        MDString::get(NewFunc->getParent()->getContext(), Name));
   for (auto &Inst : CallsWithMetadataInFunc) {
     // This map always has the initial version in it.
     assert(Inst.cloneNo() == 0);
@@ -4939,6 +4942,9 @@ static SmallVector<std::unique_ptr<ValueToValueMapTy>, 4> createFunctionClones(
       PrevF->eraseFromParent();
     } else
       NewF->setName(Name);
+    if (auto *SP = NewF->getSubprogram())
+      SP->replaceLinkageName(
+          MDString::get(NewF->getParent()->getContext(), Name));
     ORE.emit(OptimizationRemark(DEBUG_TYPE, "MemprofClone", &F)
              << "created clone " << ore::NV("NewFunction", NewF));
 

llvm/test/ThinLTO/X86/memprof-basic.ll

@@ -100,7 +100,7 @@ declare void @_ZdaPv()
 
 declare i32 @sleep()
 
-define internal ptr @_Z3barv() #0 {
+define internal ptr @_Z3barv() #0 !dbg !15 {
 entry:
   %call = call ptr @_Znam(i64 0), !memprof !2, !callsite !7
   ret ptr null
@@ -125,6 +125,9 @@ uselistorder ptr @_Z3foov, { 1, 0 }
 
 attributes #0 = { noinline optnone }
 
+!llvm.dbg.cu = !{!13}
+!llvm.module.flags = !{!20, !21}
+
 !0 = !{i64 8632435727821051414}
 !1 = !{i64 -3421689549917153178}
 !2 = !{!3, !5}
@@ -138,7 +141,15 @@ attributes #0 = { noinline optnone }
 !10 = !{i64 123, i64 100}
 !11 = !{i64 456, i64 200}
 !12 = !{i64 789, i64 300}
-
+!13 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !14, producer: "clang version 21.0.0git ([email protected]:llvm/llvm-project.git e391301e0e4d9183fe06e69602e87b0bc889aeda)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
+!14 = !DIFile(filename: "basic.cc", directory: "", checksumkind: CSK_MD5, checksum: "8636c46e81402013b9d54e8307d2f149")
+!15 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !14, file: !14, line: 1, type: !16, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !13)
+!16 = !DISubroutineType(types: !17)
+!17 = !{!18}
+!18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !19, size: 64)
+!19 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+!20 = !{i32 7, !"Dwarf Version", i32 5}
+!21 = !{i32 2, !"Debug Info Version", i32 3}
 
 ; DUMP: CCG before cloning:
 ; DUMP: Callsite Context Graph:
@@ -301,14 +312,16 @@ attributes #0 = { noinline optnone }
 ; IR:   call {{.*}} @_Z3barv()
 ; IR: define internal {{.*}} @_Z3foov()
 ; IR:   call {{.*}} @_Z3bazv()
-; IR: define internal {{.*}} @_Z3barv.memprof.1()
+; IR: define internal {{.*}} @_Z3barv.memprof.1() {{.*}} !dbg ![[SP:[0-9]+]]
 ; IR:   call {{.*}} @_Znam(i64 0) #[[COLD:[0-9]+]]
 ; IR: define internal {{.*}} @_Z3bazv.memprof.1()
 ; IR:   call {{.*}} @_Z3barv.memprof.1()
 ; IR: define internal {{.*}} @_Z3foov.memprof.1()
 ; IR:   call {{.*}} @_Z3bazv.memprof.1()
 ; IR: attributes #[[NOTCOLD]] = { "memprof"="notcold" }
 ; IR: attributes #[[COLD]] = { "memprof"="cold" }
+;; Make sure the clone's linkageName was updated.
+; IR: ![[SP]] = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv.memprof.1"
 
 
 ; STATS: 1 memprof-context-disambiguation - Number of cold static allocations (possibly cloned)

llvm/test/Transforms/MemProfContextDisambiguation/basic.ll

@@ -71,7 +71,7 @@ declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg) #1
 ; Function Attrs: nobuiltin
 declare void @_ZdaPv() #2
 
-define internal ptr @_Z3barv() #3 {
+define internal ptr @_Z3barv() #3 !dbg !15 {
 entry:
   %call = call noalias noundef nonnull ptr @_Znam(i64 noundef 10) #6, !memprof !2, !callsite !7
   ret ptr null
@@ -103,6 +103,9 @@ attributes #4 = { "stack-protector-buffer-size"="8" }
 attributes #5 = { noinline }
 attributes #6 = { builtin }
 
+!llvm.dbg.cu = !{!13}
+!llvm.module.flags = !{!20, !21}
+
 !0 = !{i64 8632435727821051414}
 !1 = !{i64 -3421689549917153178}
 !2 = !{!3, !5}
@@ -116,7 +119,15 @@ attributes #6 = { builtin }
 !10 = !{i64 123, i64 100}
 !11 = !{i64 456, i64 200}
 !12 = !{i64 789, i64 300}
-
+!13 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !14, producer: "clang version 21.0.0git ([email protected]:llvm/llvm-project.git e391301e0e4d9183fe06e69602e87b0bc889aeda)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
+!14 = !DIFile(filename: "basic.cc", directory: "", checksumkind: CSK_MD5, checksum: "8636c46e81402013b9d54e8307d2f149")
+!15 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !14, file: !14, line: 1, type: !16, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !13)
+!16 = !DISubroutineType(types: !17)
+!17 = !{!18}
+!18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !19, size: 64)
+!19 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+!20 = !{i32 7, !"Dwarf Version", i32 5}
+!21 = !{i32 2, !"Debug Info Version", i32 3}
 
 ; DUMP: CCG before cloning:
 ; DUMP: Callsite Context Graph:
@@ -270,14 +281,16 @@ attributes #6 = { builtin }
 ; IR:   call {{.*}} @_Z3barv()
 ; IR: define internal {{.*}} @_Z3foov()
 ; IR:   call {{.*}} @_Z3bazv()
-; IR: define internal {{.*}} @_Z3barv.memprof.1()
+; IR: define internal {{.*}} @_Z3barv.memprof.1() {{.*}} !dbg ![[SP:[0-9]+]]
 ; IR:   call {{.*}} @_Znam(i64 noundef 10) #[[COLD:[0-9]+]]
 ; IR: define internal {{.*}} @_Z3bazv.memprof.1()
 ; IR:   call {{.*}} @_Z3barv.memprof.1()
 ; IR: define internal {{.*}} @_Z3foov.memprof.1()
 ; IR:   call {{.*}} @_Z3bazv.memprof.1()
 ; IR: attributes #[[NOTCOLD]] = { builtin "memprof"="notcold" }
 ; IR: attributes #[[COLD]] = { builtin "memprof"="cold" }
+;; Make sure the clone's linkageName was updated.
+; IR: ![[SP]] = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv.memprof.1"
 
 
 ; STATS: 1 memprof-context-disambiguation - Number of cold static allocations (possibly cloned)