Extract openInputFile() into Support/FileUtilities

Multiple binaries have the needs to open input files. Use this function
to de-duplicate the code.

Also changed openOutputFile() to return errors using std::string since
it is a library call and accessing I/O in library call is not friendly.

PiperOrigin-RevId: 228878221

mlir/include/mlir/Support/FileUtilities.h

@@ -22,14 +22,28 @@
 #ifndef MLIR_SUPPORT_FILEUTILITIES_H_
 #define MLIR_SUPPORT_FILEUTILITIES_H_
 
-#include "mlir/Support/LLVM.h"
-#include "llvm/Support/ToolOutputFile.h"
 #include <memory>
+#include <string>
+
+namespace llvm {
+class MemoryBuffer;
+class ToolOutputFile;
+class StringRef;
+} // namespace llvm
 
 namespace mlir {
 
-/// Open the file specified by its name for writing.
-std::unique_ptr<llvm::ToolOutputFile> openOutputFile(StringRef outputFilename);
+/// Open the file specified by its name for reading. Write the error message to
+/// `errorMessage` if errors occur and `errorMessage` is not nullptr.
+std::unique_ptr<llvm::MemoryBuffer>
+openInputFile(llvm::StringRef inputFilename,
+              std::string *errorMessage = nullptr);
+
+/// Open the file specified by its name for writing. Write the error message to
+/// `errorMessage` if errors occur and `errorMessage` is not nullptr.
+std::unique_ptr<llvm::ToolOutputFile>
+openOutputFile(llvm::StringRef outputFilename,
+               std::string *errorMessage = nullptr);
 
 } // namespace mlir
 

mlir/lib/Support/FileUtilities.cpp

@@ -20,18 +20,35 @@
 //===----------------------------------------------------------------------===//
 
 #include "mlir/Support/FileUtilities.h"
+#include "mlir/Support/LLVM.h"
 #include "llvm/Support/FileUtilities.h"
+#include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/ToolOutputFile.h"
 
 using namespace mlir;
 
+std::unique_ptr<llvm::MemoryBuffer>
+mlir::openInputFile(StringRef inputFilename, std::string *errorMessage) {
+  auto fileOrErr = llvm::MemoryBuffer::getFileOrSTDIN(inputFilename);
+  if (std::error_code error = fileOrErr.getError()) {
+    if (errorMessage)
+      *errorMessage = "cannot open input file '" + inputFilename.str() +
+                      "': " + error.message();
+    return nullptr;
+  }
+
+  return std::move(*fileOrErr);
+}
+
 std::unique_ptr<llvm::ToolOutputFile>
-mlir::openOutputFile(StringRef outputFilename) {
+mlir::openOutputFile(StringRef outputFilename, std::string *errorMessage) {
   std::error_code error;
   auto result = llvm::make_unique<llvm::ToolOutputFile>(outputFilename, error,
                                                         llvm::sys::fs::F_None);
   if (error) {
-    llvm::errs() << error.message();
+    if (errorMessage)
+      *errorMessage = "cannot open output file '" + outputFilename.str() +
+                      "': " + error.message();
     return nullptr;
   }
 

mlir/lib/Target/LLVMIR/ConvertToLLVMIR.cpp

@@ -40,6 +40,7 @@
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Type.h"
+#include "llvm/Support/ToolOutputFile.h"
 
 using namespace mlir;
 

mlir/tools/mlir-opt/mlir-opt.cpp

@@ -29,6 +29,7 @@
 #include "mlir/IR/Module.h"
 #include "mlir/Parser.h"
 #include "mlir/Pass.h"
+#include "mlir/Support/FileUtilities.h"
 #include "mlir/Support/PassNameParser.h"
 #include "mlir/TensorFlow/ControlFlowOps.h"
 #include "mlir/TensorFlow/Passes.h"
@@ -71,20 +72,6 @@ static std::vector<const mlir::PassInfo *> *passList;
 
 enum OptResult { OptSuccess, OptFailure };
 
-/// Open the specified output file and return it, exiting if there is any I/O or
-/// other errors.
-static std::unique_ptr<ToolOutputFile> getOutputStream() {
-  std::error_code error;
-  auto result =
-      llvm::make_unique<ToolOutputFile>(outputFilename, error, sys::fs::F_None);
-  if (error) {
-    llvm::errs() << error.message() << '\n';
-    exit(1);
-  }
-
-  return result;
-}
-
 /// Given a MemoryBuffer along with a line and column within it, return the
 /// location being referenced.
 static SMLoc getLocFromLineAndCol(MemoryBuffer &membuf, unsigned lineNo,
@@ -150,8 +137,14 @@ static OptResult performActions(SourceMgr &sourceMgr, MLIRContext *context) {
       return OptFailure;
   }
 
+  std::string errorMessage;
+  auto output = openOutputFile(outputFilename, &errorMessage);
+  if (!output) {
+    llvm::errs() << errorMessage << "\n";
+    exit(1);
+  }
+
   // Print the output.
-  auto output = getOutputStream();
   module->print(output->os());
   output->keep();
   return OptSuccess;
@@ -381,17 +374,17 @@ int main(int argc, char **argv) {
   cl::ParseCommandLineOptions(argc, argv, "MLIR modular optimizer driver\n");
 
   // Set up the input file.
-  auto fileOrErr = MemoryBuffer::getFileOrSTDIN(inputFilename);
-  if (std::error_code error = fileOrErr.getError()) {
-    llvm::errs() << argv[0] << ": could not open input file '" << inputFilename
-                 << "': " << error.message() << "\n";
-    return 1;
+  std::string errorMessage;
+  auto file = openInputFile(inputFilename, &errorMessage);
+  if (!file) {
+    llvm::errs() << errorMessage << "\n";
+    return OptFailure;
   }
 
   // The split-input-file mode is a very specific mode that slices the file
   // up into small pieces and checks each independently.
   if (splitInputFile)
-    return splitAndProcessFile(std::move(*fileOrErr));
+    return splitAndProcessFile(std::move(file));
 
-  return processFile(std::move(*fileOrErr));
+  return processFile(std::move(file));
 }

mlir/tools/mlir-translate/mlir-translate.cpp

@@ -45,15 +45,15 @@ static llvm::cl::opt<std::string>
 
 static Module *parseMLIRInput(StringRef inputFilename, MLIRContext *context) {
   // Set up the input file.
-  auto fileOrErr = llvm::MemoryBuffer::getFileOrSTDIN(inputFilename);
-  if (std::error_code error = fileOrErr.getError()) {
-    llvm::errs() << "Could not open input file '" << inputFilename
-                 << "': " << error.message();
+  std::string errorMessage;
+  auto file = openInputFile(inputFilename, &errorMessage);
+  if (!file) {
+    llvm::errs() << errorMessage << "\n";
     return nullptr;
   }
 
   llvm::SourceMgr sourceMgr;
-  sourceMgr.AddNewSourceBuffer(std::move(*fileOrErr), llvm::SMLoc());
+  sourceMgr.AddNewSourceBuffer(std::move(file), llvm::SMLoc());
   return parseSourceFile(sourceMgr, context);
 }