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

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

This macro was added to the driver in
9d117e7 because it can be conditionally
disabled, but before that, the flag to gate behavior was removed under
the assumption it wasn't conditional in
b5b622a. This patch is to connect the
macro with the preexisting flag

Author: cyndyishida

clang-tools-extra/test/pp-trace/pp-trace-include.cpp

@@ -39,7 +39,6 @@
 // CHECK-NEXT:   Reason: EnterFile
 // CHECK-NEXT:   FileType: C_User
 // CHECK-NEXT:   PrevFID: (invalid)
-// CHECK:      - Callback: MacroDefined
 // CHECK:      - Callback: FileChanged
 // CHECK-NEXT:   Loc: "<built-in>:1:1"
 // CHECK-NEXT:   Reason: ExitFile

clang-tools-extra/test/pp-trace/pp-trace-macro.cpp

@@ -40,7 +40,6 @@ X
 // CHECK-NEXT:   MacroNameTok: __STDC_EMBED_EMPTY__
 // CHECK-NEXT:   MacroDirective: MD_Define
 // CHECK:      - Callback: MacroDefined
-// CHECK:      - Callback: MacroDefined
 // CHECK-NEXT:   MacroNameTok: MACRO
 // CHECK-NEXT:   MacroDirective: MD_Define
 // CHECK-NEXT: - Callback: MacroExpands

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.
 

clang/include/clang/Driver/Options.td

@@ -2155,8 +2155,12 @@ 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]>,

clang/lib/Driver/ToolChains/Clang.cpp

@@ -7879,10 +7879,13 @@ 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);

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);
 }

clang/test/DebugInfo/KeyInstructions/flag.cpp

@@ -8,6 +8,9 @@
 
 // KEY-INSTRUCTIONS: "-gkey-instructions"
 // NO-KEY-INSTRUCTIONS-NOT: key-instructions
+
+// Only expect one dwarf related flag.
+// NO-DEBUG: -fdwarf2-cfi-asm
 // NO-DEBUG-NOT: debug-info-kind
 // NO-DEBUG-NOT: dwarf
 

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