[PATCH] D105835: [Driver] Let -fno-integrated-as -gdwarf-5 use -fdwarf-directory-asm

[Fangrui Song via Phabricator via cfe-commits]

MaskRay created this revision.
MaskRay added reviewers: debug-info, dblaikie, osandov.
MaskRay requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

While GNU as only allows the directory form of the .file directive for DWARF v5,
the integrated prefers the directory form on all DWARF versions (-fdwarf-directory-asm).

We currently set -fno-dwarf-directory-asm for -fno-integrated-as -gdwarf-5
which will cause the directory entry 0 and the filename entry 0 to be incorrect
(see D105662 <https://reviews.llvm.org/D105662>). This patch makes -fno-integrated-as -gdwarf-5 use -fdwarf-directory-asm as well.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D105835

Files:
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/test/Driver/debug-options.c


Index: clang/test/Driver/debug-options.c
===================================================================
--- clang/test/Driver/debug-options.c
+++ clang/test/Driver/debug-options.c
@@ -424,3 +424,14 @@
 // 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'
+
+/// Default to -fno-dwarf-directory-asm for -fno-integrated-as before DWARF v5.
+// RUN: %clang -### -target x86_64 -c -gdwarf-2 %s 2>&1 | FileCheck --check-prefix=DIRECTORY %s
+// RUN: %clang -### -target x86_64 -c -gdwarf-5 %s 2>&1 | FileCheck --check-prefix=DIRECTORY %s
+// RUN: %clang -### -target x86_64 -c -gdwarf-4 -fno-integrated-as %s 2>&1 | FileCheck --check-prefix=NODIRECTORY %s
+// RUN: %clang -### -target x86_64 -c -gdwarf-5 -fno-integrated-as %s 2>&1 | FileCheck --check-prefix=DIRECTORY %s
+
+// RUN: %clang -### -target x86_64 -c -gdwarf-4 -fno-dwarf-directory-asm %s 2>&1 | FileCheck --check-prefix=NODIRECTORY %s
+
+// DIRECTORY-NOT: "-fno-dwarf-directory-asm"
+// NODIRECTORY: "-fno-dwarf-directory-asm"
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -490,14 +490,6 @@
                       Default);
 }
 
-static bool ShouldDisableDwarfDirectory(const ArgList &Args,
-                                        const ToolChain &TC) {
-  bool UseDwarfDirectory =
-      Args.hasFlag(options::OPT_fdwarf_directory_asm,
-                   options::OPT_fno_dwarf_directory_asm, TC.useIntegratedAs());
-  return !UseDwarfDirectory;
-}
-
 // Convert an arg of the form "-gN" or "-ggdbN" or one of their aliases
 // to the corresponding DebugInfoKind.
 static codegenoptions::DebugInfoKind DebugLevelToInfoKind(const Arg &A) {
@@ -4175,6 +4167,14 @@
     }
   }
 
+  // To avoid join/split of directory+filename, the integrated assembler prefers
+  // the directory form of .file on all DWARF versions. GNU as doesn't allow the
+  // form before DWARF v5.
+  if (!Args.hasFlag(options::OPT_fdwarf_directory_asm,
+                    options::OPT_fno_dwarf_directory_asm,
+                    TC.useIntegratedAs() || EffectiveDWARFVersion >= 5))
+    CmdArgs.push_back("-fno-dwarf-directory-asm");
+
   // Decide how to render forward declarations of template instantiations.
   // SCE wants full descriptions, others just get them in the name.
   if (DebuggerTuning == llvm::DebuggerKind::SCE)
@@ -5506,9 +5506,6 @@
       CmdArgs.push_back("-fno-gnu-keywords");
   }
 
-  if (ShouldDisableDwarfDirectory(Args, TC))
-    CmdArgs.push_back("-fno-dwarf-directory-asm");
-
   if (!ShouldEnableAutolink(Args, TC, JA))
     CmdArgs.push_back("-fno-autolink");
 


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