From a892974a4f1b55ce481c33b0250dbc07a37486c1 Mon Sep 17 00:00:00 2001
From: Adrian Prantl <aprantl@apple.com>
Date: Fri, 22 Jan 2016 17:43:43 +0000
Subject: [PATCH] Module Debugging: Use a nonzero DWO id for precompiled
headers. PCH files don't have a module signature and LLVM uses a nonzero DWO
id as an indicator for skeleton / module CUs. This change pins the DWO id for
PCH files to a known constant value. The correct long-term solution here is
to implement a module signature that is an actual dterministic hash (at the
moment module signatures are just random nonzero numbers) and then enable
this for PCH files as well.
<rdar://problem/24290667>
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@258507 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/CodeGen/CGDebugInfo.cpp | 5 ++++-
lib/CodeGen/ObjectFilePCHContainerOperations.cpp | 6 +++++-
test/Modules/ExtDebugInfo.cpp | 4 ++++
test/Modules/ModuleDebugInfo.cpp | 3 +--
4 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 28e28489681..4e0cc3f8574 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -1740,11 +1740,14 @@ CGDebugInfo::getOrCreateModuleRef(ExternalASTSource::ASTSourceDescriptor Mod,
bool IsRootModule = M ? !M->Parent : true;
if (CreateSkeletonCU && IsRootModule) {
+ // PCH files don't have a signature field in the control block,
+ // but LLVM detects skeleton CUs by looking for a non-zero DWO id.
+ uint64_t Signature = Mod.getSignature() ? Mod.getSignature() : ~1U;
llvm::DIBuilder DIB(CGM.getModule());
DIB.createCompileUnit(TheCU->getSourceLanguage(), Mod.getModuleName(),
Mod.getPath(), TheCU->getProducer(), true,
StringRef(), 0, Mod.getASTFile(),
- llvm::DIBuilder::FullDebug, Mod.getSignature());
+ llvm::DIBuilder::FullDebug, Signature);
DIB.finalize();
}
llvm::DIModule *Parent =
diff --git a/lib/CodeGen/ObjectFilePCHContainerOperations.cpp b/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
index cd17832554d..2178ec21c7a 100644
--- a/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
+++ b/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
@@ -219,7 +219,11 @@ public:
M->setTargetTriple(Ctx.getTargetInfo().getTriple().getTriple());
M->setDataLayout(Ctx.getTargetInfo().getDataLayoutString());
- Builder->getModuleDebugInfo()->setDwoId(Buffer->Signature);
+
+ // PCH files don't have a signature field in the control block,
+ // but LLVM detects DWO CUs by looking for a non-zero DWO id.
+ uint64_t Signature = Buffer->Signature ? Buffer->Signature : ~1U;
+ Builder->getModuleDebugInfo()->setDwoId(Signature);
// Finalize the Builder.
if (Builder)
diff --git a/test/Modules/ExtDebugInfo.cpp b/test/Modules/ExtDebugInfo.cpp
index b9eae12deda..c4c6a298234 100644
--- a/test/Modules/ExtDebugInfo.cpp
+++ b/test/Modules/ExtDebugInfo.cpp
@@ -102,3 +102,7 @@ void foo() {
// CHECK: !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !0, entity: !"_ZTSN8DebugCXX6StructE", line: 24)
+
+// CHECK: !DICompileUnit(
+// CHECK-SAME: splitDebugFilename:
+// CHECK-SAME: dwoId:
diff --git a/test/Modules/ModuleDebugInfo.cpp b/test/Modules/ModuleDebugInfo.cpp
index a2b735b3b70..73443972409 100644
--- a/test/Modules/ModuleDebugInfo.cpp
+++ b/test/Modules/ModuleDebugInfo.cpp
@@ -8,7 +8,6 @@
// RUN: %clang_cc1 -triple %itanium_abi_triple -x objective-c++ -std=c++11 -debug-info-kind=limited -fmodules -fmodule-format=obj -fimplicit-module-maps -DMODULES -fmodules-cache-path=%t %s -I %S/Inputs -I %t -emit-llvm -o %t.ll -mllvm -debug-only=pchcontainer &>%t-mod.ll
// RUN: cat %t-mod.ll | FileCheck %s
// RUN: cat %t-mod.ll | FileCheck --check-prefix=CHECK-NEG %s
-// RUN: cat %t-mod.ll | FileCheck --check-prefix=CHECK-DWO %s
// PCH:
// RUN: %clang_cc1 -triple %itanium_abi_triple -x c++ -std=c++11 -emit-pch -fmodule-format=obj -I %S/Inputs -o %t.pch %S/Inputs/DebugCXX.h -mllvm -debug-only=pchcontainer &>%t-pch.ll
@@ -22,7 +21,7 @@
// CHECK: distinct !DICompileUnit(language: DW_LANG_{{.*}}C_plus_plus,
// CHECK-SAME: isOptimized: false,
// CHECK-SAME-NOT: splitDebugFilename:
-// CHECK-DWO: dwoId:
+// CHECK: dwoId:
// CHECK: !DICompositeType(tag: DW_TAG_enumeration_type, name: "Enum"
// CHECK-SAME: identifier: "_ZTSN8DebugCXX4EnumE")
--
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