Merging r323813:

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r323813 | tejohnson | 2018-01-30 21:16:32 +0100 (Tue, 30 Jan 2018) | 14 lines

Teach ValueMapper to use ODR uniqued types when available

Summary:
This is exposed during ThinLTO compilation, when we import an alias by
creating a clone of the aliasee. Without this fix the debug type is
unnecessarily cloned and we get a duplicate, undoing the uniquing.

Fixes PR36089.

Reviewers: mehdi_amini, pcc

Subscribers: eraman, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D41669
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llvm-svn: 323854

llvm/lib/Transforms/Utils/ValueMapper.cpp

@@ -25,6 +25,7 @@
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/Constant.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalAlias.h"
@@ -536,13 +537,23 @@ Optional<Metadata *> MDNodeMapper::tryToMapOperand(const Metadata *Op) {
   return None;
 }
 
+static Metadata *cloneOrBuildODR(const MDNode &N) {
+  auto *CT = dyn_cast<DICompositeType>(&N);
+  // If ODR type uniquing is enabled, we would have uniqued composite types
+  // with identifiers during bitcode reading, so we can just use CT.
+  if (CT && CT->getContext().isODRUniquingDebugTypes() &&
+      CT->getIdentifier() != "")
+    return const_cast<DICompositeType *>(CT);
+  return MDNode::replaceWithDistinct(N.clone());
+}
+
 MDNode *MDNodeMapper::mapDistinctNode(const MDNode &N) {
   assert(N.isDistinct() && "Expected a distinct node");
   assert(!M.getVM().getMappedMD(&N) && "Expected an unmapped node");
-  DistinctWorklist.push_back(cast<MDNode>(
-      (M.Flags & RF_MoveDistinctMDs)
-          ? M.mapToSelf(&N)
-          : M.mapToMetadata(&N, MDNode::replaceWithDistinct(N.clone()))));
+  DistinctWorklist.push_back(
+      cast<MDNode>((M.Flags & RF_MoveDistinctMDs)
+                       ? M.mapToSelf(&N)
+                       : M.mapToMetadata(&N, cloneOrBuildODR(N))));
   return DistinctWorklist.back();
 }
 

llvm/test/ThinLTO/X86/Inputs/dicompositetype-unique-alias.ll

@@ -0,0 +1,39 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-scei-ps4"
+
+%struct.CFVS = type { %struct.Vec }
+%struct.Vec = type { i8 }
+%struct.S = type { i8 }
+
+@_ZN4CFVSD1Ev = alias void (%struct.CFVS*), void (%struct.CFVS*)* @_ZN4CFVSD2Ev
+
+define void @_ZN4CFVSD2Ev(%struct.CFVS* %this) unnamed_addr align 2 !dbg !8 {
+entry:
+  %this.addr = alloca %struct.CFVS*, align 8
+  store %struct.CFVS* %this, %struct.CFVS** %this.addr, align 8
+  %this1 = load %struct.CFVS*, %struct.CFVS** %this.addr, align 8
+  %m_val = getelementptr inbounds %struct.CFVS, %struct.CFVS* %this1, i32 0, i32 0
+  ret void
+}
+
+declare dereferenceable(1) %struct.S* @_Z3Getv()
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 6.0.0 (trunk 321360) (llvm/trunk 321359)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "bz188598-b.cpp", directory: "")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 2}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!8 = distinct !DISubprogram(name: "~CFVS", linkageName: "_ZN4CFVSD2Ev", scope: !9, file: !1, line: 2, type: !28, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false, unit: !0, declaration: !27, variables: !2)
+!9 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "CFVS", file: !10, line: 7, size: 8, elements: !11, identifier: "_ZTS4CFVS")
+!10 = !DIFile(filename: "./bz188598.h", directory: "")
+!11 = !{!35}
+!27 = !DISubprogram(name: "~CFVS", scope: !9, file: !10, line: 8, type: !28, isLocal: false, isDefinition: false, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false)
+!28 = !DISubroutineType(types: !29)
+!29 = !{null, !30}
+!30 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !9, size: 64, flags: DIFlagArtificial | DIFlagObjectPointer)
+!35 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)

llvm/test/ThinLTO/X86/dicompositetype-unique-alias.ll

@@ -0,0 +1,62 @@
+; RUN: opt -module-summary -o %t1.bc %s
+; RUN: opt -module-summary -o %t2.bc %S/Inputs/dicompositetype-unique-alias.ll
+; RUN: llvm-lto --thinlto-action=run %t1.bc %t2.bc -thinlto-save-temps=%t3.
+; RUN: llvm-dis %t3.0.3.imported.bc -o - | FileCheck %s
+; RUN: llvm-lto2 run %t1.bc %t2.bc -o %t --save-temps \
+; RUN: -r %t1.bc,_ZN1CD2Ev,pl \
+; RUN: -r %t1.bc,_ZN4CFVSD1Ev,l \
+; RUN: -r %t1.bc,_ZN4CFVSD2Ev,l \
+; RUN: -r %t1.bc,_Z3Getv,l \
+; RUN: -r %t2.bc,_ZN4CFVSD1Ev,pl \
+; RUN: -r %t2.bc,_ZN4CFVSD2Ev,pl \
+; RUN: -r %t2.bc,_Z3Getv,l
+; RUN: llvm-dis %t.1.3.import.bc -o - | FileCheck %s
+
+; Only llvm-lto2 adds the dso_local keyword, hence the {{.*}}
+; CHECK: define available_externally{{.*}} void @_ZN4CFVSD1Ev
+
+; Confirm that we only have a single DICompositeType after importing
+; both an alias and its aliasee, since ODR Type Uniquing is enabled.
+; CHECK: DICompositeType
+; CHECK-NOT: DICompositeType
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-scei-ps4"
+
+%class.C = type <{ i32 (...)**, %class.A, %struct.CFVS, [6 x i8] }>
+%class.A = type { %struct.Vec }
+%struct.Vec = type { i8 }
+%struct.CFVS = type { %struct.Vec }
+%struct.S = type { i8 }
+
+define void @_ZN1CD2Ev(%class.C* %this) unnamed_addr align 2 {
+entry:
+  %this.addr = alloca %class.C*, align 8
+  %this1 = load %class.C*, %class.C** %this.addr, align 8
+  %m = getelementptr inbounds %class.C, %class.C* %this1, i32 0, i32 2
+  call void @_ZN4CFVSD1Ev(%struct.CFVS* %m), !dbg !50
+  call void @_ZN4CFVSD2Ev(%struct.CFVS* %m), !dbg !50
+  ret void
+}
+
+declare void @_ZN4CFVSD1Ev(%struct.CFVS*) unnamed_addr
+declare void @_ZN4CFVSD2Ev(%struct.CFVS*) unnamed_addr
+
+declare dereferenceable(1) %struct.S* @_Z3Getv()
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 6.0.0 (trunk 321360) (llvm/trunk 321359)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "bz188598-a.cpp", directory: ".")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 2}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!8 = distinct !DISubprogram(name: "~C", linkageName: "_ZN1CD2Ev", scope: !1, file: !1, line: 9, type: !47, isLocal: false, isDefinition: true, scopeLine: 9, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
+!47 = !DISubroutineType(types: !48)
+!48 = !{!55}
+!50 = !DILocation(line: 9, scope: !51)
+!51 = distinct !DILexicalBlock(scope: !8, file: !1, line: 9)
+!55 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)