[llvm-rc] Use proper search algorithm for finding resources.

Previously we would only look in the current directory for a
resource, which might not be the same as the directory of the
rc file.  Furthermore, MSVC rc supports a /I option, and can
also look in the system environment.  This patch adds support
for this search algorithm.

Differential Revision: https://reviews.llvm.org/D38740

llvm-svn: 315499

1 files changed, 13 insertions, 4 deletions

diff --git a/llvm/lib/Support/Process.cpp b/llvm/lib/Support/Process.cpp
index caec993ee16..1c8cc6e83ad 100644
--- a/llvm/lib/Support/Process.cpp
+++ b/llvm/lib/Support/Process.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/Process.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Config/config.h"
 #include "llvm/Support/FileSystem.h"
@@ -26,9 +27,14 @@ using namespace sys;
 //===          independent code.
 //===----------------------------------------------------------------------===//
 
-Optional<std::string> Process::FindInEnvPath(const std::string& EnvName,
-                                             const std::string& FileName)
-{
+Optional<std::string> Process::FindInEnvPath(StringRef EnvName,
+                                             StringRef FileName) {
+  return FindInEnvPath(EnvName, FileName, {});
+}
+
+Optional<std::string> Process::FindInEnvPath(StringRef EnvName,
+                                             StringRef FileName,
+                                             ArrayRef<std::string> IgnoreList) {
   assert(!path::is_absolute(FileName));
   Optional<std::string> FoundPath;
   Optional<std::string> OptPath = Process::GetEnv(EnvName);
@@ -39,10 +45,13 @@ Optional<std::string> Process::FindInEnvPath(const std::string& EnvName,
   SmallVector<StringRef, 8> Dirs;
   SplitString(OptPath.getValue(), Dirs, EnvPathSeparatorStr);
 
-  for (const auto &Dir : Dirs) {
+  for (StringRef Dir : Dirs) {
     if (Dir.empty())
       continue;
 
+    if (any_of(IgnoreList, [&](StringRef S) { return fs::equivalent(S, Dir); }))
+      continue;
+
     SmallString<128> FilePath(Dir);
     path::append(FilePath, FileName);
     if (fs::exists(Twine(FilePath))) {