llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang-modules
Author: Michael Buch (Michael137)
<details>
<summary>Changes</summary>
In Objective-C, forward declarations are currently represented as:
```
DW_TAG_structure_type
DW_AT_name ("Foo")
DW_AT_declaration (true)
DW_AT_APPLE_runtime_class (DW_LANG_ObjC)
```
However, when compiling with `-gmodules`, when a class definition is turned
into a forward declaration within a `DW_TAG_module`, the DIE for the forward
declaration looks as follows:
```
DW_TAG_structure_type
DW_AT_name ("Foo")
DW_AT_declaration (true)
```
Note the absence of `DW_AT_APPLE_runtime_class`. With recent changes in LLDB,
not being able to differentiate between C++ and Objective-C forward
declarations has become problematic (see attached test-case and explanation in
https://github.com/llvm/llvm-project/pull/119860).
---
Full diff: https://github.com/llvm/llvm-project/pull/120154.diff
4 Files Affected:
- (modified) clang/lib/CodeGen/CGDebugInfo.cpp (+6-5)
- (modified) clang/test/Modules/ExtDebugInfo.m (+2-1)
- (modified) clang/test/Modules/ModuleDebugInfo.m (+1)
- (added) lldb/test/Shell/SymbolFile/DWARF/objc-gmodules-class-extension.test
(+34)
``````````diff
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp
b/clang/lib/CodeGen/CGDebugInfo.cpp
index 60f32f76109e9a..ff27690d47b080 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -2995,20 +2995,21 @@ llvm::DIType *CGDebugInfo::CreateType(const
ObjCInterfaceType *Ty,
if (!ID)
return nullptr;
+ auto RuntimeLang =
+ static_cast<llvm::dwarf::SourceLanguage>(TheCU->getSourceLanguage());
+
// Return a forward declaration if this type was imported from a clang
module,
// and this is not the compile unit with the implementation of the type
(which
// may contain hidden ivars).
if (DebugTypeExtRefs && ID->isFromASTFile() && ID->getDefinition() &&
!ID->getImplementation())
- return DBuilder.createForwardDecl(llvm::dwarf::DW_TAG_structure_type,
- ID->getName(),
- getDeclContextDescriptor(ID), Unit, 0);
+ return DBuilder.createForwardDecl(
+ llvm::dwarf::DW_TAG_structure_type, ID->getName(),
+ getDeclContextDescriptor(ID), Unit, 0, RuntimeLang);
// Get overall information about the record type for the debug info.
llvm::DIFile *DefUnit = getOrCreateFile(ID->getLocation());
unsigned Line = getLineNumber(ID->getLocation());
- auto RuntimeLang =
- static_cast<llvm::dwarf::SourceLanguage>(TheCU->getSourceLanguage());
// If this is just a forward declaration return a special forward-declaration
// debug type since we won't be able to lay out the entire type.
diff --git a/clang/test/Modules/ExtDebugInfo.m
b/clang/test/Modules/ExtDebugInfo.m
index b6a8b2676e5ba4..e2611ae5300634 100644
--- a/clang/test/Modules/ExtDebugInfo.m
+++ b/clang/test/Modules/ExtDebugInfo.m
@@ -75,7 +75,8 @@ int foo(ObjCClass *c) {
// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "ObjCClass",
// CHECK-SAME: scope: ![[MOD]],
-// CHECK-SAME: flags: DIFlagFwdDecl)
+// CHECK-SAME: flags: DIFlagFwdDecl,
+// CHECK-SAME: runtimeLang: DW_LANG_ObjC)
// CHECK-NOT: !DICompositeType(tag: DW_TAG_structure_type,
// CHECK: !DICompositeType(tag: DW_TAG_enumeration_type,
diff --git a/clang/test/Modules/ModuleDebugInfo.m
b/clang/test/Modules/ModuleDebugInfo.m
index 62c6fd68dd8546..c527c43a0f4a2c 100644
--- a/clang/test/Modules/ModuleDebugInfo.m
+++ b/clang/test/Modules/ModuleDebugInfo.m
@@ -39,6 +39,7 @@
// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "FwdDecl",
// CHECK-SAME: scope: ![[MODULE]],
+// CHECK-SAME: runtimeLang: DW_LANG_ObjC
// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "ObjCClass",
// CHECK-SAME: scope: ![[MODULE]],
diff --git
a/lldb/test/Shell/SymbolFile/DWARF/objc-gmodules-class-extension.test
b/lldb/test/Shell/SymbolFile/DWARF/objc-gmodules-class-extension.test
new file mode 100644
index 00000000000000..330a6b338c4723
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/objc-gmodules-class-extension.test
@@ -0,0 +1,34 @@
+# REQUIRES: system-darwin
+
+# Test that we can set a breakpoint in a method of a class extension.
+# This requires us to parse the method into an AST type, and the context
+# too (which in DWARF is just a forward declaration).
+#
+# RUN: split-file %s %t
+# RUN: %clangxx_host %t/lib.m -c -g -gmodules -fmodules -o %t/lib.o
+# RUN: %clangxx_host %t/main.m -g -gmodules -fmodules %t/lib.o -o %t/a.out
-framework Foundation
+#
+# RUN: %lldb %t/a.out -o "breakpoint set -f lib.m -l 6" -o exit | FileCheck %s
+
+# CHECK: (lldb) breakpoint set -f lib.m -l 6
+# CHECK: Breakpoint 1: where = a.out`-[NSObject(Foo) func]
+
+#--- main.m
+int main() {
+ return 0;
+}
+
+#--- lib.m
+#import <Foundation/Foundation.h>
+
+@implementation NSObject (Foo)
+- (NSError *)func {
+ NSLog(@"Hello, World!");
+ return 0;
+}
+@end
+
+NSObject * func() {
+ return 0;
+}
+
``````````
</details>
https://github.com/llvm/llvm-project/pull/120154
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