[DebugInfo] make DW_LANG_C11 respect -gstrict-dwarf

[dblaikie]

clang/lib/CodeGen/CGDebugInfo.cpp

581–582

Generally, I think, we downgrade to the nearest/highest version? (for instance today when the user requests C17, they get C11, not C - and when they request C++17 they get C_plus_plus_14, not plain C_plus_plus) I see there's the same choice up in the C++ case too, but not sure it's the right one?

Should probably do the same thing for strict dwarf, and emit this as C99?

[shchenz]

address @dblaikie comments

[shchenz]

clang/lib/CodeGen/CGDebugInfo.cpp

581–582

Fair enough.

[dblaikie]

Looks good

clang/lib/CodeGen/CGDebugInfo.cpp

else
       LangTag = llvm::dwarf::DW_LANG_C_plus_plus;
   } else if (LO.ObjC) {
     LangTag = llvm::dwarf::DW_LANG_ObjC;
   } else if (LO.OpenCL && (!CGM.getCodeGenOpts().DebugStrictDwarf ||
                            CGM.getCodeGenOpts().DwarfVersion >= 5)) {
     LangTag = llvm::dwarf::DW_LANG_OpenCL;
   } else if (LO.RenderScript) {
     LangTag = llvm::dwarf::DW_LANG_GOOGLE_RenderScript;
-  } else if (LO.C11) {
+  } else if (LO.C11 && !(CGO.DebugStrictDwarf && CGO.DwarfVersion < 5)) {
       LangTag = llvm::dwarf::DW_LANG_C11;
   } else if (LO.C99) {
     LangTag = llvm::dwarf::DW_LANG_C99;
   } else {
     LangTag = llvm::dwarf::DW_LANG_C89;
   }
 
   std::string Producer = getClangFullVersion();
 

clang/test/CodeGen/debug-info-programming-language.c

 // RUN: %clang_cc1 -dwarf-version=3 -emit-llvm -triple %itanium_abi_triple %s -o - \
 // RUN:   -x c -std=c11 -O0 -disable-llvm-passes -debug-info-kind=limited \
 // RUN:   | FileCheck --check-prefix=CHECK-C11 %s
 // RUN: %clang_cc1 -dwarf-version=3 -emit-llvm -triple %itanium_abi_triple %s -o - \
 // RUN:   -x c -std=c17 -O0 -disable-llvm-passes -debug-info-kind=limited \
 // RUN:   | FileCheck --check-prefix=CHECK-C17 %s
+// RUN: %clang_cc1 -dwarf-version=3 -emit-llvm -triple %itanium_abi_triple %s -o - \
+// RUN:   -x c -std=c11 -O0 -disable-llvm-passes -debug-info-kind=limited \
+// RUN:   -gstrict-dwarf | FileCheck --check-prefix=CHECK-STRICT %s
+// RUN: %clang_cc1 -dwarf-version=5 -emit-llvm -triple %itanium_abi_triple %s -o - \
+// RUN:   -x c -std=c11 -O0 -disable-llvm-passes -debug-info-kind=limited \
+// RUN:   -gstrict-dwarf | FileCheck --check-prefix=CHECK-C11 %s
 
+// CHECK-STRICT: !DICompileUnit(language: DW_LANG_C99
 // CHECK-C11: !DICompileUnit(language: DW_LANG_C11
 // Update this check once support for DW_LANG_C17 is broadly supported/known in
 // consumers. Maybe we'll skip this and go to the DWARFv6 language+version
 // encoding that avoids the risk of regression when describing a language
 // version newer than what the consumer is aware of.
 // CHECK-C17: !DICompileUnit(language: DW_LANG_C11
 
 void f1(void) { }