vsk created this revision.
vsk added reviewers: teemperor, jasonmolenda, rjmccall.
LLDB may synthesize decls using asm labels. These decls cannot have a
mangle different than the one specified in the label name. I.e., the
mangle-suppression prefix should not be added.
Fixes an expression evaluation failure in lldb's TestVirtual.py on iOS.
rdar://45827323
https://reviews.llvm.org/D67774
Files:
clang/include/clang/AST/ExternalASTSource.h
clang/lib/AST/Mangle.cpp
clang/test/Import/asm-label-mangle/Inputs/asm-label.cpp
clang/test/Import/asm-label-mangle/test.cpp
clang/tools/clang-import-test/clang-import-test.cpp
lldb/include/lldb/Symbol/ClangExternalASTSourceCommon.h
Index: lldb/include/lldb/Symbol/ClangExternalASTSourceCommon.h
===================================================================
--- lldb/include/lldb/Symbol/ClangExternalASTSourceCommon.h
+++ lldb/include/lldb/Symbol/ClangExternalASTSourceCommon.h
@@ -132,6 +132,11 @@
static ClangExternalASTSourceCommon *Lookup(clang::ExternalASTSource *source);
+ // Request that no "hidden" prefix is added to the mangle for asm labels.
+ // LLDB synthesizes many decls as simple asm labels: these synthesized decls
+ // cannot have a mangle different than the one specified in the label name.
+ bool UseGlobalPrefixInAsmLabelMangle() override { return false; }
+
private:
typedef llvm::DenseMap<const void *, ClangASTMetadata> MetadataMap;
Index: clang/tools/clang-import-test/clang-import-test.cpp
===================================================================
--- clang/tools/clang-import-test/clang-import-test.cpp
+++ clang/tools/clang-import-test/clang-import-test.cpp
@@ -231,6 +231,18 @@
namespace {
+// A mock ExternalASTMerger, used for testing purposes.
+class MockExternalASTMerger : public clang::ExternalASTMerger {
+public:
+ MockExternalASTMerger(const ImporterTarget &Target,
+ llvm::ArrayRef<ImporterSource> Sources)
+ : clang::ExternalASTMerger(Target, Sources) {}
+
+ // Disallow use of a global prefix in the mangle for asm labels. This is
+ // required by lldb.
+ bool UseGlobalPrefixInAsmLabelMangle() override { return false; }
+};
+
/// A container for a CompilerInstance (possibly with an ExternalASTMerger
/// attached to its ASTContext).
///
@@ -265,7 +277,7 @@
for (CIAndOrigins &Import : Imports)
Sources.push_back({Import.getASTContext(), Import.getFileManager(),
Import.getOriginMap()});
- auto ES = std::make_unique<ExternalASTMerger>(Target, Sources);
+ auto ES = std::make_unique<MockExternalASTMerger>(Target, Sources);
CI.getASTContext().setExternalSource(ES.release());
CI.getASTContext().getTranslationUnitDecl()->setHasExternalVisibleStorage();
}
Index: clang/test/Import/asm-label-mangle/test.cpp
===================================================================
--- /dev/null
+++ clang/test/Import/asm-label-mangle/test.cpp
@@ -0,0 +1,9 @@
+// RUN: clang-import-test -dump-ir -import %S/Inputs/asm-label.cpp -expression %s | FileCheck %s
+
+// The asm label mangle should not include a mangle-suppression prefix.
+
+// CHECK: define void @someotherfunc
+
+void expr() {
+ S1().func1();
+}
Index: clang/test/Import/asm-label-mangle/Inputs/asm-label.cpp
===================================================================
--- /dev/null
+++ clang/test/Import/asm-label-mangle/Inputs/asm-label.cpp
@@ -0,0 +1,4 @@
+struct S1 {
+ void func1() __asm("someotherfunc") {
+ }
+};
Index: clang/lib/AST/Mangle.cpp
===================================================================
--- clang/lib/AST/Mangle.cpp
+++ clang/lib/AST/Mangle.cpp
@@ -127,10 +127,13 @@
// tricks normally used for producing aliases (PR9177). Fortunately the
// llvm mangler on ELF is a nop, so we can just avoid adding the \01
// marker. We also avoid adding the marker if this is an alias for an
- // LLVM intrinsic.
+ // LLVM intrinsic, or if the external AST source which provided the decl
+ // opts out of this behavior.
char GlobalPrefix =
getASTContext().getTargetInfo().getDataLayout().getGlobalPrefix();
- if (GlobalPrefix && !ALA->getLabel().startswith("llvm."))
+ ExternalASTSource *Source = getASTContext().getExternalSource();
+ if (GlobalPrefix && !ALA->getLabel().startswith("llvm.") &&
+ (!Source || Source->UseGlobalPrefixInAsmLabelMangle()))
Out << '\01'; // LLVM IR Marker for __asm("foo")
Out << ALA->getLabel();
Index: clang/include/clang/AST/ExternalASTSource.h
===================================================================
--- clang/include/clang/AST/ExternalASTSource.h
+++ clang/include/clang/AST/ExternalASTSource.h
@@ -104,6 +104,10 @@
/// The default implementation of this method is a no-op.
virtual Decl *GetExternalDecl(uint32_t ID);
+ /// Allow use of a global prefix (as defined in DataLayout) in the mangle
+ /// for asm labels. Defaults to true.
+ virtual bool UseGlobalPrefixInAsmLabelMangle() { return true; }
+
/// Resolve a selector ID into a selector.
///
/// This operation only needs to be implemented if the AST source
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