From abc5db1075b4dd1e4faa8fdcc8593b08fca80c2a Mon Sep 17 00:00:00 2001
From: Martin Storsjo <martin@martin.st>
Date: Thu, 17 Aug 2017 05:58:27 +0000
Subject: [PATCH] [llvm-dlltool] Don't crash if no def file is provided or it
 can't be opened

Differential Revision: https://reviews.llvm.org/D36780

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311068 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../llvm-dlltool/DlltoolDriver.cpp            | 21 ++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp b/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp
index 40fc48f9803..64fe11a4e36 100644
--- a/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp
+++ b/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp
@@ -60,11 +60,13 @@ std::vector<std::unique_ptr<MemoryBuffer>> OwningMBs;
 
 // Opens a file. Path has to be resolved already.
 // Newly created memory buffers are owned by this driver.
-MemoryBufferRef openFile(StringRef Path) {
+Optional<MemoryBufferRef> openFile(StringRef Path) {
   ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MB = MemoryBuffer::getFile(Path);
 
-  if (std::error_code EC = MB.getError())
+  if (std::error_code EC = MB.getError()) {
     llvm::errs() << "fail openFile: " << EC.message() << "\n";
+    return None;
+  }
 
   MemoryBufferRef MBRef = MB.get()->getMemBufferRef();
   OwningMBs.push_back(std::move(MB.get())); // take ownership
@@ -115,11 +117,16 @@ int llvm::dlltoolDriverMain(llvm::ArrayRef<const char *> ArgsArr) {
   for (auto *Arg : Args.filtered(OPT_UNKNOWN))
     llvm::errs() << "ignoring unknown argument: " << Arg->getSpelling() << "\n";
 
-  MemoryBufferRef MB;
-  if (auto *Arg = Args.getLastArg(OPT_d))
-    MB = openFile(Arg->getValue());
+  if (!Args.hasArg(OPT_d)) {
+    llvm::errs() << "no definition file specified\n";
+    return 1;
+  }
+
+  Optional<MemoryBufferRef> MB = openFile(Args.getLastArg(OPT_d)->getValue());
+  if (!MB)
+    return 1;
 
-  if (!MB.getBufferSize()) {
+  if (!MB->getBufferSize()) {
     llvm::errs() << "definition file empty\n";
     return 1;
   }
@@ -134,7 +141,7 @@ int llvm::dlltoolDriverMain(llvm::ArrayRef<const char *> ArgsArr) {
   }
 
   Expected<COFFModuleDefinition> Def =
-      parseCOFFModuleDefinition(MB, Machine, true);
+      parseCOFFModuleDefinition(*MB, Machine, true);
 
   if (!Def) {
     llvm::errs() << "error parsing definition\n"
-- 
2.50.1