[clang] [clang] Make "__GCC_HAVE_DWARF2_CFI_ASM" a proper predefined macro (PR #165731)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Cyndy Ishida (cyndyishida)

<details>
<summary>Changes</summary>

Use a flag to determine whether this macro should be set when intializing the preprocessor.

This macro was added to the driver in 9d117e7b2a399a9b2bcf53fb9b9c0946e82dc75c because it can be conditionally disabled, but before that, the flag to gate behavior was removed under the assumption it wasn't conditional in b5b622a03c5136fa10d245dbe1f8f278ebd98d1b. This patch is to connect the macro with the preexisting flag

---
Full diff: https://github.com/llvm/llvm-project/pull/165731.diff


5 Files Affected:

- (modified) clang/include/clang/Basic/DebugOptions.def (+2) 
- (modified) clang/include/clang/Driver/Options.td (+6-2) 
- (modified) clang/lib/Driver/ToolChains/Clang.cpp (+6-3) 
- (modified) clang/lib/Frontend/InitPreprocessor.cpp (+3) 
- (modified) clang/test/Preprocessor/unwind-tables.c (+2) 


``````````diff
diff --git a/clang/include/clang/Basic/DebugOptions.def b/clang/include/clang/Basic/DebugOptions.def
index a768b12fa4e0d..ea3636ffa1af1 100644
--- a/clang/include/clang/Basic/DebugOptions.def
+++ b/clang/include/clang/Basic/DebugOptions.def
@@ -46,6 +46,8 @@ ENUM_DEBUGOPT(EmitDwarfUnwind, EmitDwarfUnwindType, 2,
 DEBUGOPT(NoDwarfDirectoryAsm , 1, 0, Benign) ///< Set when -fno-dwarf-directory-asm
                                              ///< is enabled.
 
+DEBUGOPT(Dwarf2CFIAsm, 1, 0, NotCompatible) ///< Set when -fdwarf2-cfi-asm is enabled.
+
 DEBUGOPT(NoInlineLineTables, 1, 0, Benign) ///< Whether debug info should contain
                                            ///< inline line tables.
 
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index cb5cb888c6da7..bec05a40df1fa 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -2154,8 +2154,12 @@ defm dollars_in_identifiers : BoolFOption<"dollars-in-identifiers",
   PosFlag<SetTrue, [], [ClangOption], "Allow">,
   NegFlag<SetFalse, [], [ClangOption], "Disallow">,
   BothFlags<[], [ClangOption, CC1Option], " '$' in identifiers">>;
-def fdwarf2_cfi_asm : Flag<["-"], "fdwarf2-cfi-asm">, Group<clang_ignored_f_Group>;
-def fno_dwarf2_cfi_asm : Flag<["-"], "fno-dwarf2-cfi-asm">, Group<clang_ignored_f_Group>;
+
+defm dwarf2_cfi_asm
+    : BoolFOption<"dwarf2-cfi-asm", CodeGenOpts<"Dwarf2CFIAsm">, DefaultFalse,
+                  PosFlag<SetTrue, [], [ClangOption, CC1Option]>,
+                  NegFlag<SetFalse>>;
+
 defm dwarf_directory_asm : BoolFOption<"dwarf-directory-asm",
   CodeGenOpts<"NoDwarfDirectoryAsm">, DefaultFalse,
   NegFlag<SetTrue, [], [ClangOption, CC1Option]>,
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 4e8f63ea49480..b7e081663e782 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -7878,10 +7878,13 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                        !TC.getTriple().isAndroid() && TC.useIntegratedAs()))
     CmdArgs.push_back("-faddrsig");
 
-  if ((Triple.isOSBinFormatELF() || Triple.isOSBinFormatMachO()) &&
+  const bool HasDefaultDwarf2CFIASM =
+      (Triple.isOSBinFormatELF() || Triple.isOSBinFormatMachO()) &&
       (EH || UnwindTables || AsyncUnwindTables ||
-       DebugInfoKind != llvm::codegenoptions::NoDebugInfo))
-    CmdArgs.push_back("-D__GCC_HAVE_DWARF2_CFI_ASM=1");
+       DebugInfoKind != llvm::codegenoptions::NoDebugInfo);
+  if (Args.hasFlag(options::OPT_fdwarf2_cfi_asm,
+                   options::OPT_fno_dwarf2_cfi_asm, HasDefaultDwarf2CFIASM))
+    CmdArgs.push_back("-fdwarf2-cfi-asm");
 
   if (Arg *A = Args.getLastArg(options::OPT_fsymbol_partition_EQ)) {
     std::string Str = A->getAsString(Args);
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 47f1d5a6b636c..b374e4f665672 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -1516,6 +1516,9 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   if (LangOpts.PointerAuthIntrinsics)
     Builder.defineMacro("__PTRAUTH__");
 
+  if (CGOpts.Dwarf2CFIAsm)
+    Builder.defineMacro("__GCC_HAVE_DWARF2_CFI_ASM");
+
   // Get other target #defines.
   TI.getTargetDefines(LangOpts, Builder);
 }
diff --git a/clang/test/Preprocessor/unwind-tables.c b/clang/test/Preprocessor/unwind-tables.c
index 0a863d79adbf6..5ff990d0c40a6 100644
--- a/clang/test/Preprocessor/unwind-tables.c
+++ b/clang/test/Preprocessor/unwind-tables.c
@@ -1,11 +1,13 @@
 // RUN: %clang %s -dM -E -target x86_64-windows | FileCheck %s --check-prefix=NO
 // RUN: %clang %s -dM -E -target x86_64 -fno-asynchronous-unwind-tables | FileCheck %s --check-prefix=NO
+// RUN: %clang %s -dM -E -target x86_64 -fno-dwarf2-cfi-asm | FileCheck %s --check-prefix=NO
 
 // RUN: %clang %s -dM -E -target x86_64 | FileCheck %s
 // RUN: %clang %s -dM -E -target x86_64 -funwind-tables -fno-asynchronous-unwind-tables -g | FileCheck %s
 // RUN: %clang %s -dM -E -target aarch64-apple-darwin | FileCheck %s
 // RUN: %clang %s -dM -E -target x86_64 -fno-asynchronous-unwind-tables -g | FileCheck %s
 // RUN: %clang %s -dM -E -target x86_64 -fno-asynchronous-unwind-tables -fexceptions | FileCheck %s
+// RUN: %clang %s -dM -E -target x86_64-windows -fdwarf2-cfi-asm | FileCheck %s
 
 // NO-NOT: #define __GCC_HAVE_DWARF2_CFI_ASM
 // CHECK: #define __GCC_HAVE_DWARF2_CFI_ASM 1

``````````

</details>


https://github.com/llvm/llvm-project/pull/165731