[PATCH] D45255: [CodeGen] Add an option to suppress output of llvm.ident

[Mikhail Maltsev via Phabricator via cfe-commits]

miyuki created this revision.
miyuki added a reviewer: faisalv.
Herald added subscribers: JDevlieghere, aprantl.

By default Clang outputs its version (including git commit hash, in
case of trunk builds) into object and assembly files. It might be
useful to have an option to disable this, especially for debugging
purposes.
This patch implements new command line flags -Qn and -Qy (the names
are chosen for compatibility with GCC). -Qn disables output of
the 'llvm.ident' metadata string and the 'producer' debug info. -Qy
(enabled by default) does the opposite.


https://reviews.llvm.org/D45255

Files:
  include/clang/Driver/Options.td
  include/clang/Frontend/CodeGenOptions.def
  lib/CodeGen/CGDebugInfo.cpp
  lib/CodeGen/CodeGenModule.cpp
  lib/Driver/ToolChains/Clang.cpp
  lib/Frontend/CompilerInvocation.cpp
  test/CodeGen/no-ident-version.c


Index: test/CodeGen/no-ident-version.c
===================================================================
--- /dev/null
+++ test/CodeGen/no-ident-version.c
@@ -0,0 +1,5 @@
+// RUN: %clang_cc1 -Qn -emit-llvm -debug-info-kind=limited -o - %s | FileCheck %s
+
+// CHECK-NOT: llvm.ident
+// CHECK-NOT: producer:
+int main(void) {}
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -1070,6 +1070,8 @@
   Opts.EmitCheckPathComponentsToStrip = getLastArgIntValue(
       Args, OPT_fsanitize_undefined_strip_path_components_EQ, 0, Diags);
 
+  Opts.EmitVersionIdentMetadata = Args.hasFlag(OPT_Qy, OPT_Qn, true);
+
   return Success;
 }
 
Index: lib/Driver/ToolChains/Clang.cpp
===================================================================
--- lib/Driver/ToolChains/Clang.cpp
+++ lib/Driver/ToolChains/Clang.cpp
@@ -4392,6 +4392,9 @@
     }
   }
 
+  if (!Args.hasFlag(options::OPT_Qy, options::OPT_Qn, true))
+    CmdArgs.push_back("-Qn");
+
   // -fcommon is the default unless compiling kernel code or the target says so
   bool NoCommonDefault = KernelOrKext || isNoCommonDefault(RawTriple);
   if (!Args.hasFlag(options::OPT_fcommon, options::OPT_fno_common,
Index: lib/CodeGen/CodeGenModule.cpp
===================================================================
--- lib/CodeGen/CodeGenModule.cpp
+++ lib/CodeGen/CodeGenModule.cpp
@@ -568,7 +568,8 @@
   if (DebugInfo)
     DebugInfo->finalize();
 
-  EmitVersionIdentMetadata();
+  if (getCodeGenOpts().EmitVersionIdentMetadata)
+    EmitVersionIdentMetadata();
 
   EmitTargetMetadata();
 }
Index: lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- lib/CodeGen/CGDebugInfo.cpp
+++ lib/CodeGen/CGDebugInfo.cpp
@@ -577,7 +577,8 @@
                           remapDIPath(getCurrentDirname()),
                           CSInfo,
                           getSource(SM, SM.getMainFileID())),
-      Producer, LO.Optimize || CGOpts.PrepareForLTO || CGOpts.EmitSummaryIndex,
+      CGOpts.EmitVersionIdentMetadata ? Producer : "",
+      LO.Optimize || CGOpts.PrepareForLTO || CGOpts.EmitSummaryIndex,
       CGOpts.DwarfDebugFlags, RuntimeVers,
       CGOpts.EnableSplitDwarf ? "" : CGOpts.SplitDwarfFile, EmissionKind,
       0 /* DWOid */, CGOpts.SplitDwarfInlining, CGOpts.DebugInfoForProfiling,
Index: include/clang/Frontend/CodeGenOptions.def
===================================================================
--- include/clang/Frontend/CodeGenOptions.def
+++ include/clang/Frontend/CodeGenOptions.def
@@ -68,6 +68,7 @@
                                      ///< Decl* various IR entities came from.
                                      ///< Only useful when running CodeGen as a
                                      ///< subroutine.
+CODEGENOPT(EmitVersionIdentMetadata , 1, 1) ///< Emit compiler version metadata.
 CODEGENOPT(EmitGcovArcs      , 1, 0) ///< Emit coverage data files, aka. GCDA.
 CODEGENOPT(EmitGcovNotes     , 1, 0) ///< Emit coverage "notes" files, aka GCNO.
 CODEGENOPT(EmitOpenCLArgMetadata , 1, 0) ///< Emit OpenCL kernel arg metadata.
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -396,7 +396,10 @@
 def Ofast : Joined<["-"], "Ofast">, Group<O_Group>, Flags<[CC1Option]>;
 def P : Flag<["-"], "P">, Flags<[CC1Option]>, Group<Preprocessor_Group>,
   HelpText<"Disable linemarker output in -E mode">;
-def Qn : Flag<["-"], "Qn">, IgnoredGCCCompat;
+def Qy : Flag<["-"], "Qy">, Flags<[CC1Option]>,
+  HelpText<"Emit metadata containing compiler name and version">;
+def Qn : Flag<["-"], "Qn">, Flags<[CC1Option]>,
+  HelpText<"Do not emit metadata containing compiler name and version">;
 def Qunused_arguments : Flag<["-"], "Qunused-arguments">, Flags<[DriverOption, CoreOption]>,
   HelpText<"Don't emit warning for unused driver arguments">;
 def Q : Flag<["-"], "Q">, IgnoredGCCCompat;


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D45255.140943.patch
Type: text/x-patch
Size: 4098 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20180404/eef7ec18/attachment.bin>