[PATCH] D92809: [Driver] Add -gno-split-dwarf which can disable debug fission

[Fangrui Song via Phabricator via cfe-commits]

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

Currently when -gsplit-dwarf is specified (could be buried in a build system),
there is no convenient way to cancel debug fission without affecting the debug
information amount (all of -g0, -g1 -fsplit-dwarf-inlining, and -gline-directives-only
can, but they affect the debug information amount).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D92809

Files:
  clang/include/clang/Driver/Options.td
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/test/Driver/split-debug.c


Index: clang/test/Driver/split-debug.c
===================================================================
--- clang/test/Driver/split-debug.c
+++ clang/test/Driver/split-debug.c
@@ -17,12 +17,21 @@
 // RUN: %clang -### -c -target amdgcn-amd-amdhsa -gsplit-dwarf -g %s 2>&1 | FileCheck %s --check-prefix=SPLIT
 
 /// -gsplit-dwarf is a no-op on a non-ELF platform.
-// RUN: %clang -### -c -target x86_64-apple-darwin  -gsplit-dwarf -g %s 2>&1 | FileCheck %s --check-prefix=NOSPLIT
-// NOSPLIT-NOT: "-split-dwarf
+// RUN: %clang -### -c -target x86_64-apple-darwin  -gsplit-dwarf -g %s 2>&1 | FileCheck %s --check-prefix=DARWIN
+// DARWIN:     "-debug-info-kind=standalone"
+// DARWIN-NOT: "-split-dwarf
 
 /// -gsplit-dwarf is a no-op if no -g is specified.
 // RUN: %clang -### -c -target x86_64 -gsplit-dwarf %s 2>&1 | FileCheck %s --check-prefix=G0
 
+/// -gno-split-dwarf disables debug fission.
+// RUN: %clang -### -c -target x86_64 -gsplit-dwarf -g -gno-split-dwarf %s 2>&1 | FileCheck %s --check-prefix=NOSPLIT
+// RUN: %clang -### -c -target x86_64 -gsplit-dwarf=single -g -gno-split-dwarf %s 2>&1 | FileCheck %s --check-prefix=NOSPLIT
+// RUN: %clang -### -c -target x86_64 -gno-split-dwarf -g -gsplit-dwarf %s 2>&1 | FileCheck %s --check-prefixes=NOINLINE,SPLIT
+
+// NOSPLIT:     "-debug-info-kind=limited"
+// NOSPLIT-NOT: "-split-dwarf
+
 /// Test -gsplit-dwarf=single.
 // RUN: %clang -### -c -target x86_64 -gsplit-dwarf=single -g %s 2>&1 | FileCheck %s --check-prefix=SINGLE
 
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -3705,9 +3705,9 @@
 
 static DwarfFissionKind getDebugFissionKind(const Driver &D,
                                             const ArgList &Args, Arg *&Arg) {
-  Arg =
-      Args.getLastArg(options::OPT_gsplit_dwarf, options::OPT_gsplit_dwarf_EQ);
-  if (!Arg)
+  Arg = Args.getLastArg(options::OPT_gsplit_dwarf, options::OPT_gsplit_dwarf_EQ,
+                        options::OPT_gno_split_dwarf);
+  if (!Arg || Arg->getOption().matches(options::OPT_gno_split_dwarf))
     return DwarfFissionKind::None;
 
   if (Arg->getOption().matches(options::OPT_gsplit_dwarf))
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -2208,6 +2208,7 @@
 def gsplit_dwarf_EQ : Joined<["-"], "gsplit-dwarf=">, Group<g_flags_Group>,
   HelpText<"Set DWARF fission mode to either 'split' or 'single'">,
   Values<"split,single">;
+def gno_split_dwarf : Flag<["-"], "gno-split-dwarf">, Group<g_flags_Group>;
 def ggnu_pubnames : Flag<["-"], "ggnu-pubnames">, Group<g_flags_Group>, Flags<[CC1Option]>;
 def gno_gnu_pubnames : Flag<["-"], "gno-gnu-pubnames">, Group<g_flags_Group>;
 def gpubnames : Flag<["-"], "gpubnames">, Group<g_flags_Group>, Flags<[CC1Option]>;


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