Michael137 created this revision.
Michael137 added reviewers: aprantl, dblaikie.
Herald added a project: All.
Michael137 requested review of this revision.
Herald added projects: clang, LLDB.
Herald added subscribers: lldb-commits, cfe-commits.
**Summary**
This patch makes debug-info generation aware of the
`[[clang::preferred_name]]` attribute. The attribute tells clang
to print the annotated class template as some typedef (e.g., in
diagnostics).
When printing a typename for emission into `DW_AT_name` this patch now
uses the preferred_name (if available). This is behind an LLDB tuning
because by default we try to avoid diverging GCC and Clang typename
format (which is why the `PrintingPolicy::UsePreferredNames` has
previously been disabled by default in `CGDebugInfo`).
**Motivation**
This will reduce noise in type summaries when showing variable
types in LLDB. E.g.,:
(lldb) v
(std::vector<std::basic_string<char> >) vec = size=0 {}
becomes
(lldb) v
(std::vector<std::string>) vec = size=0 {}
**Testing**
- Added Clang test
- Adjusted LLDB API tests
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D143501
Files:
clang/lib/CodeGen/CGDebugInfo.cpp
clang/lib/CodeGen/CGDebugInfo.h
clang/test/CodeGen/debug-info-preferred-names.cpp
lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/shared_ptr/TestDataFormatterLibcxxSharedPtr.py
lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/unique_ptr/TestDataFormatterLibcxxUniquePtr.py
Index: lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/unique_ptr/TestDataFormatterLibcxxUniquePtr.py
===================================================================
--- lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/unique_ptr/TestDataFormatterLibcxxUniquePtr.py
+++ lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/unique_ptr/TestDataFormatterLibcxxUniquePtr.py
@@ -22,7 +22,7 @@
def make_expected_basic_string_ptr(self) -> str:
if self.expectedCompilerVersion(['>', '16.0']):
- return f'std::unique_ptr<std::basic_string<char> >'
+ return f'std::unique_ptr<std::string>'
else:
return 'std::unique_ptr<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, ' \
'std::default_delete<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >'
Index: lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/shared_ptr/TestDataFormatterLibcxxSharedPtr.py
===================================================================
--- lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/shared_ptr/TestDataFormatterLibcxxSharedPtr.py
+++ lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/shared_ptr/TestDataFormatterLibcxxSharedPtr.py
@@ -59,13 +59,13 @@
self.assertNotEqual(valobj.child[0].unsigned, 0)
if self.expectedCompilerVersion(['>', '16.0']):
- string_type = "std::basic_string<char>"
+ string_type = "std::string"
else:
- string_type = "std::basic_string<char, std::char_traits<char>, std::allocator<char> >"
+ string_type = "std::basic_string<char, std::char_traits<char>, std::allocator<char> > "
valobj = self.expect_var_path(
"sp_str",
- type="std::shared_ptr<" + string_type + " >",
+ type="std::shared_ptr<" + string_type + ">",
children=[ValueCheck(name="__ptr_", summary='"hello"')],
)
self.assertRegex(valobj.summary, r'^"hello"( strong=1)? weak=1$')
Index: clang/test/CodeGen/debug-info-preferred-names.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGen/debug-info-preferred-names.cpp
@@ -0,0 +1,42 @@
+// RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited %s -o - -debugger-tuning=lldb | FileCheck --check-prefixes=COMMON,LLDB %s
+// RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited %s -o - -debugger-tuning=gdb | FileCheck --check-prefixes=COMMON,GDB %s
+
+template<typename T>
+class Qux {};
+
+template<typename T>
+struct Foo;
+
+template<typename T>
+using Bar = Foo<T>;
+
+template<typename T>
+struct [[clang::preferred_name(Bar<T>)]] Foo {};
+
+int main() {
+ /* Trivial cases */
+
+ Bar<int> b;
+// COMMON: !DIDerivedType(tag: DW_TAG_typedef, name: "Bar<int>"
+
+ Foo<int> f1;
+// COMMON: !DICompositeType(tag: DW_TAG_structure_type, name: "Foo<int>"
+
+ /* Alias template case */
+
+ Bar<Foo<int>> f2;
+// GDB: !DIDerivedType(tag: DW_TAG_typedef, name: "Bar<Foo<int> >"
+// LLDB: !DIDerivedType(tag: DW_TAG_typedef, name: "Bar<Bar<int> >"
+
+ /* Nested cases */
+
+ Foo<Foo<int>> f3;
+// GDB: !DICompositeType(tag: DW_TAG_structure_type, name: "Foo<Foo<int> >"
+// LLDB: !DICompositeType(tag: DW_TAG_structure_type, name: "Foo<Bar<int> >"
+
+ Qux<Foo<int>> f4;
+// GDB: !DICompositeType(tag: DW_TAG_class_type, name: "Qux<Foo<int> >"
+// LLDB: !DICompositeType(tag: DW_TAG_class_type, name: "Qux<Bar<int> >"
+
+ return 0;
+}
Index: clang/lib/CodeGen/CGDebugInfo.h
===================================================================
--- clang/lib/CodeGen/CGDebugInfo.h
+++ clang/lib/CodeGen/CGDebugInfo.h
@@ -789,6 +789,11 @@
std::memcpy(Data + A.size(), B.data(), B.size());
return StringRef(Data, A.size() + B.size());
}
+
+ /// Returns the QualType of the typedef that the PreferredNameAttr
+ /// of 'orig' refers to, if any such attribute exists. Returns 'orig'
+ /// otherwise.
+ QualType maybeGetPreferredNameType(QualType orig) const;
};
/// A scoped helper to set the current debug location to the specified
Index: clang/lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- clang/lib/CodeGen/CGDebugInfo.cpp
+++ clang/lib/CodeGen/CGDebugInfo.cpp
@@ -250,7 +250,7 @@
PP.SuppressInlineNamespace = false;
PP.PrintCanonicalTypes = true;
- PP.UsePreferredNames = false;
+ PP.UsePreferredNames = CGM.getCodeGenOpts().getDebuggerTuning() == llvm::DebuggerKind::LLDB;
PP.AlwaysIncludeTypeForTemplateArgument = true;
PP.UseEnumerators = false;
@@ -2016,7 +2016,8 @@
switch (TA.getKind()) {
case TemplateArgument::Type: {
- llvm::DIType *TTy = getOrCreateType(TA.getAsType(), Unit);
+ llvm::DIType *TTy =
+ getOrCreateType(maybeGetPreferredNameType(TA.getAsType()), Unit);
TemplateParams.push_back(DBuilder.createTemplateTypeParameter(
TheCU, Name, TTy, defaultParameter));
@@ -2029,7 +2030,8 @@
} break;
case TemplateArgument::Declaration: {
const ValueDecl *D = TA.getAsDecl();
- QualType T = TA.getParamTypeForDecl().getDesugaredType(CGM.getContext());
+ QualType T = maybeGetPreferredNameType(
+ TA.getParamTypeForDecl().getDesugaredType(CGM.getContext()));
llvm::DIType *TTy = getOrCreateType(T, Unit);
llvm::Constant *V = nullptr;
// Skip retrieve the value if that template parameter has cuda device
@@ -4461,7 +4463,7 @@
if (VD->hasAttr<BlocksAttr>())
Ty = EmitTypeForVarWithBlocksAttr(VD, &XOffset).WrappedType;
else
- Ty = getOrCreateType(VD->getType(), Unit);
+ Ty = getOrCreateType(maybeGetPreferredNameType(VD->getType()), Unit);
// If there is no debug info for this type then do not emit debug info
// for this variable.
@@ -5760,3 +5762,12 @@
return llvm::DINode::FlagAllCallsDescribed;
}
+
+QualType CGDebugInfo::maybeGetPreferredNameType(QualType orig) const {
+ if (CGM.getCodeGenOpts().getDebuggerTuning() == llvm::DebuggerKind::LLDB)
+ if (auto *RecordDecl = orig->getAsCXXRecordDecl())
+ if (auto *Attr = RecordDecl->getAttr<PreferredNameAttr>())
+ return Attr->getTypedefType();
+
+ return orig;
+}
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