[Driver] Honor "-gdwarf-N" at any position for assembler sources

[ikudrin]

Summary

This fixes an issue when -gdwarf-N switch was ignored if it was given before another debug option.

[MaskRay]

clang/test/Driver/debug-options-as.c

65

Nit: use the more common spelling -fintegrated-as

-triple %itanium_abi_triple

msvc windows triples ideally don't need -dwarf-version=, but that can be a separate clean-up.

[ikudrin]

Thanks!

clang/test/Driver/debug-options-as.c

65

Nit: use the more common spelling -fintegrated-as

-integrated-as is what other tests in this file use. Is it OK if these lines will not follow the common template?

[MaskRay]

clang/test/Driver/debug-options-as.c

65

I think it should be fine...

[gregmiller]

Hello, we are seeing failures like below:

---

Note: Google Test filter = ParameterizedCovMapTest/CoverageMappingTest.skip_duplicate_function_record/0
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from ParameterizedCovMapTest/CoverageMappingTest
[ RUN ] ParameterizedCovMapTest/CoverageMappingTest.skip_duplicate_function_record/0
/scratch/build_jenkins/workspace/Downstream_Changes/llvm_cgt/llvm-project/llvm/unittests/ProfileData/CoverageMappingTest.cpp:889: Failure
Expected: 3U
Which is: 3
To be equal to: NumFuncs
Which is: 5
[ FAILED ] ParameterizedCovMapTest/CoverageMappingTest.skip_duplicate_function_record/0, where GetParam() = (false, false) (0 ms)

Do you have any suggestions on why we would start seeing above failures after you commit? Was passing before.

Thanks
Greg

[ikudrin]

In D96865#2575486, @gregmiller wrote:

Do you have any suggestions on why we would start seeing above failures after you commit? Was passing before.

From my understanding, the areas seem to be perfectly unrelated.

clang/lib/Driver/ToolChains/Clang.cpp

static unsigned DwarfVersionNum(StringRef ArgValue) {
   return llvm::StringSwitch<unsigned>(ArgValue)
       .Case("-gdwarf-2", 2)
       .Case("-gdwarf-3", 3)
       .Case("-gdwarf-4", 4)
       .Case("-gdwarf-5", 5)
       .Default(0);
 }
 
+// Find a DWARF format version option.
+// This function is a complementary for DwarfVersionNum().
+static const Arg *getDwarfNArg(const ArgList &Args) {
+  return Args.getLastArg(options::OPT_gdwarf_2, options::OPT_gdwarf_3,
+                         options::OPT_gdwarf_4, options::OPT_gdwarf_5,
+                         options::OPT_gdwarf);
+}
+
 static void RenderDebugEnablingArgs(const ArgList &Args, ArgStringList &CmdArgs,
                                     codegenoptions::DebugInfoKind DebugInfoKind,
                                     unsigned DwarfVersion,
                                     llvm::DebuggerKind DebuggerTuning) {
   switch (DebugInfoKind) {
   case codegenoptions::DebugDirectivesOnly:
     CmdArgs.push_back("-debug-info-kind=line-directives-only");
     break;
if (checkDebugInfoOption(A, Args, D, TC)) {
       else if (A->getOption().matches(options::OPT_gsce))
         DebuggerTuning = llvm::DebuggerKind::SCE;
       else
         DebuggerTuning = llvm::DebuggerKind::GDB;
     }
   }
 
   // If a -gdwarf argument appeared, remember it.
-  const Arg *GDwarfN = Args.getLastArg(
-      options::OPT_gdwarf_2, options::OPT_gdwarf_3, options::OPT_gdwarf_4,
-      options::OPT_gdwarf_5, options::OPT_gdwarf);
+  const Arg *GDwarfN = getDwarfNArg(Args);
   bool EmitDwarf = false;
   if (GDwarfN) {
     if (checkDebugInfoOption(GDwarfN, Args, D, TC))
       EmitDwarf = true;
     else
       GDwarfN = nullptr;
   }
 
void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
   while (SourceAction->getKind() != Action::InputClass) {
     assert(!SourceAction->getInputs().empty() && "unexpected root action!");
     SourceAction = SourceAction->getInputs()[0];
   }
 
   // Forward -g and handle debug info related flags, assuming we are dealing
   // with an actual assembly file.
   bool WantDebug = false;
-  unsigned DwarfVersion = 0;
   Args.ClaimAllArgs(options::OPT_g_Group);
-  if (Arg *A = Args.getLastArg(options::OPT_g_Group)) {
+  if (Arg *A = Args.getLastArg(options::OPT_g_Group))
     WantDebug = !A->getOption().matches(options::OPT_g0) &&
                 !A->getOption().matches(options::OPT_ggdb0);
-    if (WantDebug)
-      DwarfVersion = DwarfVersionNum(A->getSpelling());
-  }
 
-  unsigned DefaultDwarfVersion = ParseDebugDefaultVersion(getToolChain(), Args);
-  if (DwarfVersion == 0)
-    DwarfVersion = DefaultDwarfVersion;
+  unsigned DwarfVersion = ParseDebugDefaultVersion(getToolChain(), Args);
+  if (const Arg *GDwarfN = getDwarfNArg(Args))
+    DwarfVersion = DwarfVersionNum(GDwarfN->getSpelling());
 
   if (DwarfVersion == 0)
     DwarfVersion = getToolChain().GetDefaultDwarfVersion();
 
   codegenoptions::DebugInfoKind DebugInfoKind = codegenoptions::NoDebugInfo;
 
   if (SourceAction->getType() == types::TY_Asm ||
       SourceAction->getType() == types::TY_PP_Asm) {

clang/test/Driver/debug-options-as.c

 // RUN: %clang -### -c -gdwarf64 -gdwarf-4 -target i386-linux-gnu %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=GDWARF64_32ARCH %s
 // RUN: %clang -### -c -gdwarf64 -gdwarf-4 -target x86_64-apple-darwin %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=GDWARF64_ELF %s
 //
 // GDWARF64_VER:  error: invalid argument '-gdwarf64' only allowed with 'DWARFv3 or greater'
 // GDWARF64_32ARCH: error: invalid argument '-gdwarf64' only allowed with '64 bit architecture'
 // GDWARF64_ELF: error: invalid argument '-gdwarf64' only allowed with 'ELF platforms'
+
+// Check that -gdwarf-N can be placed before other options of the "-g" group.
+// RUN: %clang -### -c -g -gdwarf-3 -target %itanium_abi_triple -fintegrated-as -x assembler %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=DWARF3 %s
+// RUN: %clang -### -c -gdwarf-3 -g -target %itanium_abi_triple -fintegrated-as -x assembler %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=DWARF3 %s
+// RUN: %clang -### -c -g -gdwarf-5 -target %itanium_abi_triple -fintegrated-as -x assembler %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=DWARF5 %s
+// RUN: %clang -### -c -gdwarf-5 -g -target %itanium_abi_triple -fintegrated-as -x assembler %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=DWARF5 %s
+
+// DWARF3: "-cc1as"
+// DWARF3: "-dwarf-version=3"
+// DWARF5: "-cc1as"
+// DWARF5: "-dwarf-version=5"