No longer emitting a PCH file when using -fsyntax-only on a header file. Fixes PR13343.

llvm-svn: 161019

3 files changed, 13 insertions, 3 deletions

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 5be60b8806f..671c0acaab2 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1210,8 +1210,14 @@ Action *Driver::ConstructPhaseAction(const ArgList &Args, phases::ID Phase,
     }
     return new PreprocessJobAction(Input, OutputTy);
   }
-  case phases::Precompile:
-    return new PrecompileJobAction(Input, types::TY_PCH);
+  case phases::Precompile: {
+    types::ID OutputTy = types::TY_PCH;
+    if (Args.hasArg(options::OPT_fsyntax_only)) {
+      // Syntax checks should not emit a PCH file
+      OutputTy = types::TY_Nothing;
+    }
+    return new PrecompileJobAction(Input, OutputTy);
+  }
   case phases::Compile: {
     if (Args.hasArg(options::OPT_fsyntax_only)) {
       return new CompileJobAction(Input, types::TY_Nothing);
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index e13f709185f..189ff5954a8 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -1537,7 +1537,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     // Use PCH if the user requested it.
     bool UsePCH = D.CCCUsePCH;
 
-    if (UsePCH)
+    if (JA.getType() == types::TY_Nothing)
+      CmdArgs.push_back("-fsyntax-only");
+    else if (UsePCH)
       CmdArgs.push_back("-emit-pch");
     else
       CmdArgs.push_back("-emit-pth");
diff --git a/clang/test/Driver/clang_f_opts.h b/clang/test/Driver/clang_f_opts.h
new file mode 100644
index 00000000000..e48d0cfc7c1
--- /dev/null
+++ b/clang/test/Driver/clang_f_opts.h
@@ -0,0 +1,2 @@
+// RUN: %clang -### -fsyntax-only %s 2>&1 | FileCheck %s
+// CHECK: -fsyntax-only