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

Summary:
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.

Reviewers: faisalv, echristo, aprantl

Reviewed By: aprantl

Subscribers: aprantl, cfe-commits, JDevlieghere, rogfer01

Differential Revision: https://reviews.llvm.org/D45255

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@330442 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index ca6267dad4e3afbce18bfc09d6247a1b80bf5770..5290d8ad482d0bcaa2485dce0ce07910f6955852 100644 (file)
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -396,7 +396,10 @@ def O_flag : Flag<["-"], "O">, Flags<[CC1Option]>, Alias<O>, AliasArgs<["2"]>;
 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;

diff --git a/include/clang/Frontend/CodeGenOptions.def b/include/clang/Frontend/CodeGenOptions.def
index 684f99e1de308cd6e25d0cd65476789894a764a8..1684dbdb5576d062ab8e359b5c78022901c2f73f 100644 (file)
--- a/include/clang/Frontend/CodeGenOptions.def
+++ b/include/clang/Frontend/CodeGenOptions.def
@@ -69,6 +69,7 @@ CODEGENOPT(EmitDeclMetadata  , 1, 0) ///< Emit special metadata indicating what
                                      ///< 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.

diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index bdd326d70e4028771d44d9716d31b3d893538e6a..474018c065e6aeadd86fbdd5884afc0910df1d41 100644 (file)
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -577,7 +577,8 @@ void CGDebugInfo::CreateCompileUnit() {
                           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,

diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 17d9db3399f29eb71cc1d2cd7a1c7745c93058d8..707b826418aabb3f1a68a4f9d3911dc5dc28f4ef 100644 (file)
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -571,7 +571,8 @@ void CodeGenModule::Release() {
   if (DebugInfo)
     DebugInfo->finalize();
 
-  EmitVersionIdentMetadata();
+  if (getCodeGenOpts().EmitVersionIdentMetadata)
+    EmitVersionIdentMetadata();
 
   EmitTargetMetadata();
 }

diff --git a/lib/Driver/ToolChains/Clang.cpp b/lib/Driver/ToolChains/Clang.cpp
index a3cb0f21ed557328450a8f8bdc6ac5ac2d049d0e..6c5e2caae4acda894f3fc4a72bd84cb89403cffe 100644 (file)
--- a/lib/Driver/ToolChains/Clang.cpp
+++ b/lib/Driver/ToolChains/Clang.cpp
@@ -4408,6 +4408,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
+  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,

diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 67e15b41add119b54d073c39cd455900780d9b61..f904e65e7243d34fe6cd740c9e847091fe5ffbc0 100644 (file)
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1112,6 +1112,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.EmitCheckPathComponentsToStrip = getLastArgIntValue(
       Args, OPT_fsanitize_undefined_strip_path_components_EQ, 0, Diags);
 
+  Opts.EmitVersionIdentMetadata = Args.hasFlag(OPT_Qy, OPT_Qn, true);
+
   return Success;
 }
 

diff --git a/test/CodeGen/no-ident-version.c b/test/CodeGen/no-ident-version.c
new file mode 100644 (file)
index 0000000..35f84f0
--- /dev/null
+++ b/test/CodeGen/no-ident-version.c
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited -o - %s \
+// RUN:   | FileCheck --check-prefix=CHECK-NONE %s
+// RUN: %clang_cc1 -Qn -emit-llvm -debug-info-kind=limited -o - %s \
+// RUN:   | FileCheck --check-prefix=CHECK-QN %s
+// RUN: %clang_cc1 -Qy -emit-llvm -debug-info-kind=limited -o - %s \
+// RUN:   | FileCheck --check-prefix=CHECK-QY %s
+
+// CHECK-NONE: define i32 @main()
+// CHECK-NONE: llvm.ident
+// CHECK-NONE: producer:
+
+// CHECK-QN: define i32 @main()
+// CHECK-QN-NOT: llvm.ident
+// CHECK-QN-NOT: producer:
+
+// CHECK-QY: define i32 @main()
+// CHECK-QY: llvm.ident
+// CHECK-QY: producer:
+int main(void) {}