[HIP] Fix default output file for -E

[yaxunl]

Summary

By convention the default output file for -E is "-" (stdout).
This is expected by tools like ccache, which uses output
of -E to determine if a file and its dependence has changed.

Currently clang does not use stdout as default output file for -E
for HIP, which causes ccache not working.

This patch fixes that.

[tra]

clang/test/Driver/hip-output-file-name.hip

13–15

What does it mean for -E to be used when we compile for host and multiple devices. I believe for CUDA clang errors out unless there's only one sub-compilation. What does HIP do when it's run with -E -o - ?

Looks like CUDA (and, maybe HIP, too) has a bug there. -E will run preprocess on all subcompilations. -E -o - will error out claiming that you can't use -o for multiple output files, even though -### shows the same -o - in all subcompilations in both cases.

[yaxunl]

clang/test/Driver/hip-output-file-name.hip

13–15

HIP will emit a clang-offload-bundler file in textual format. Clang is able to consume this file by unbundling it. I think ccache uses it to generate a hash to check if a file and its dependent header files have changed. Since this bundled file is in text format, ccache is able to use it to generate a hash which covers both host dependence and device dependence.

[tra]

LGTM.

clang/test/Driver/hip-output-file-name.hip

13–15

That would explain why I sometimes get a screenfull of noise when I do something like that with HIP. :-/
My expectation of -E [-o -] is that I get the text of preprocessed source. In this regard, CUDA's concatenate all preprocessd outputs is a bit better than HIPs' "here's a binary blob with preprocessed output inside".

This is a bit of a mess that's beyond the scope of this CL and should be dealt with separately.

clang/lib/Driver/Driver.cpp

if (!llvm::sys::path::has_extension(ArgValue)) {
     }
 
     llvm::sys::path::replace_extension(Filename, Extension);
   }
 
   return Args.MakeArgString(Filename.c_str());
 }
 
+static bool HasPreprocessOutput(const Action &JA) {
+  if (isa<PreprocessJobAction>(JA))
+    return true;
+  if (isa<OffloadAction>(JA) && isa<PreprocessJobAction>(JA.getInputs()[0]))
+    return true;
+  if (isa<OffloadBundlingJobAction>(JA) &&
+      HasPreprocessOutput(*(JA.getInputs()[0])))
+    return true;
+  return false;
+}
+
 const char *Driver::GetNamedOutputPath(Compilation &C, const JobAction &JA,
                                        const char *BaseInput,
                                        StringRef BoundArch, bool AtTopLevel,
                                        bool MultipleArchs,
                                        StringRef OffloadingPrefix) const {
   llvm::PrettyStackTraceString CrashInfo("Computing output path");
   // Output to a user requested destination?
   if (AtTopLevel && !isa<DsymutilJobAction>(JA) && !isa<VerifyJobAction>(JA)) {
if (C.getArgs().hasArg(options::OPT__SLASH_P)) {
     if (Arg *A = C.getArgs().getLastArg(options::OPT__SLASH_Fi))
       NameArg = A->getValue();
     return C.addResultFile(
         MakeCLOutputFilename(C.getArgs(), NameArg, BaseName, types::TY_PP_C),
         &JA);
   }
 
   // Default to writing to stdout?
-  if (AtTopLevel && !CCGenDiagnostics && isa<PreprocessJobAction>(JA))
+  if (AtTopLevel && !CCGenDiagnostics && HasPreprocessOutput(JA)) {
     return "-";
+  }
 
   // Is this the assembly listing for /FA?
   if (JA.getType() == types::TY_PP_Asm &&
       (C.getArgs().hasArg(options::OPT__SLASH_FA) ||
        C.getArgs().hasArg(options::OPT__SLASH_Fa))) {
     // Use /Fa and the input filename to determine the asm file name.
     StringRef BaseName = llvm::sys::path::filename(BaseInput);
     StringRef FaValue = C.getArgs().getLastArgValue(options::OPT__SLASH_Fa);

clang/test/Driver/hip-output-file-name.hip

 // REQUIRES: clang-driver
 // REQUIRES: x86-registered-target
 // REQUIRES: amdgpu-registered-target
 
 // RUN: %clang -### -c -target x86_64-linux-gnu -fgpu-rdc \
 // RUN:   --cuda-gpu-arch=gfx803 --cuda-gpu-arch=gfx900 %s \
 // RUN: 2>&1 | FileCheck %s
 
 // CHECK: {{.*}}clang-offload-bundler{{.*}}"-outputs=hip-output-file-name.o"
+
+// Check -E default output is "-" (stdout).
+
+// RUN: %clang -### -E -target x86_64-linux-gnu \
+// RUN:   --cuda-gpu-arch=gfx803 --cuda-gpu-arch=gfx900 %s \
+// RUN: 2>&1 | FileCheck -check-prefixes=DASH %s
+
+// RUN: %clang -### -E -save-temps -target x86_64-linux-gnu \
+// RUN:   --cuda-gpu-arch=gfx803 --cuda-gpu-arch=gfx900 %s \
+// RUN: 2>&1 | FileCheck -check-prefixes=DASH %s
+
+// DASH: {{.*}}clang-offload-bundler{{.*}}"-outputs=-"
+
+// Check -E with -o.
+
+// RUN: %clang -### -E -o test.cui -target x86_64-linux-gnu \
+// RUN:   --cuda-gpu-arch=gfx803 --cuda-gpu-arch=gfx900 %s \
+// RUN: 2>&1 | FileCheck -check-prefixes=OUT %s
+
+// RUN: %clang -### -E -o test.cui -save-temps -target x86_64-linux-gnu \
+// RUN:   --cuda-gpu-arch=gfx803 --cuda-gpu-arch=gfx900 %s \
+// RUN: 2>&1 | FileCheck -check-prefixes=OUT %s
+
+// OUT: {{.*}}clang-offload-bundler{{.*}}"-outputs=test.cui"