[dxil2spv] Print missing runtime errors (#4481)

- Emit a diagnostic when input cannot be parsed.
- Add exception handling code, for exceptions that can originate from
  DXC utility code.

This cannot be easily tested with FileCheck because we would have to
negate the dxil2spv return code.

Author: kuhar

tools/clang/tools/dxil2spv/dxil2spvmain.cpp

@@ -34,6 +34,7 @@
 #include "dxc/Support/HLSLOptions.h"
 #include "dxc/Support/WinAdapter.h"
 #include "dxc/Support/dxcapi.use.h"
+#include "dxc/Support/exception.h"
 #include "dxc/dxcapi.h"
 #include "lib/dxil2spv.h"
 #include "clang/Frontend/CompilerInstance.h"
@@ -43,6 +44,8 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MSFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
+#include <cstdlib>
+#include <exception>
 #include <string>
 
 // Command line options for dxil2spv. The general approach is to mirror the
@@ -82,24 +85,37 @@ int main(int argc, const char **argv_) {
     return EXIT_SUCCESS;
   }
 
-  // Setup a compiler instance with diagnostics.
-  clang::CompilerInstance instance;
-  auto *diagnosticPrinter = new clang::TextDiagnosticPrinter(
-      llvm::errs(), new clang::DiagnosticOptions());
-  instance.createDiagnostics(diagnosticPrinter, false);
-  instance.setOutStream(&llvm::outs());
+  try {
+    // Setup a compiler instance with diagnostics.
+    clang::CompilerInstance instance;
+    auto *diagnosticPrinter = new clang::TextDiagnosticPrinter(
+        llvm::errs(), new clang::DiagnosticOptions());
+    instance.createDiagnostics(diagnosticPrinter, false);
+    instance.setOutStream(&llvm::outs());
 
-  // TODO: Allow configuration of targetEnv via options.
-  instance.getCodeGenOpts().SpirvOptions.targetEnv = "vulkan1.0";
+    // TODO: Allow configuration of targetEnv via options.
+    instance.getCodeGenOpts().SpirvOptions.targetEnv = "vulkan1.0";
 
-  // Set input and ouptut filenames.
-  instance.getCodeGenOpts().MainFileName = optInputFilename;
-  instance.getFrontendOpts().OutputFile = optOutputFilename;
+    // Set input and ouptut filenames.
+    instance.getCodeGenOpts().MainFileName = optInputFilename;
+    instance.getFrontendOpts().OutputFile = optOutputFilename;
 
-  // Run translator.
-  clang::dxil2spv::Translator translator(instance);
-  translator.Run();
+    // Run translator.
+    clang::dxil2spv::Translator translator(instance);
+    translator.Run();
 
-  return instance.getDiagnosticClient().getNumErrors() > 0 ? EXIT_FAILURE
-                                                           : EXIT_SUCCESS;
+    if (instance.getDiagnosticClient().getNumErrors() > 0)
+      return EXIT_FAILURE;
+  } catch (const hlsl::Exception& ex) {
+    llvm::errs() << "Exception: " << ex.msg << "(HRESULT: " << ex.hr << ")\n";
+    return EXIT_FAILURE;
+  } catch (const std::exception &ex) {
+    llvm::errs() << "Exception: " << ex.what() << "\n";
+    return EXIT_FAILURE;
+  } catch (...) {
+    llvm::errs() << "Unknown exception\n";
+    return EXIT_FAILURE;
+  }
+
+  return EXIT_SUCCESS;
 }

tools/clang/tools/dxil2spv/lib/dxil2spv.cpp

@@ -71,7 +71,11 @@ void Translator::Run() {
     // Get DXIL program from container.
     const hlsl::DxilPartHeader *partHeader =
         hlsl::GetDxilPartByType(blobHeader, hlsl::DxilFourCC::DFCC_DXIL);
-    IFTBOOL(partHeader != nullptr, DXC_E_MISSING_PART);
+    if (partHeader == nullptr) {
+      emitError("Could not process input. Missing DXContainer part header.");
+      return;
+    }
+
     const hlsl::DxilProgramHeader *programHeader =
         reinterpret_cast<const hlsl::DxilProgramHeader *>(
             GetDxilPartData(partHeader));