ScanDirForExecutable on Windows fails to find executables with the "exe" extension in name

When the driver tries to locate a program by its name, e.g. a linker, it
scans the paths provided by the toolchain using the ScanDirForExecutable
function. If the lookup fails, the driver uses
llvm::sys::findProgramByName. Unlike llvm::sys::findProgramByName,
ScanDirForExecutable is not aware of file extensions. If the program has
the "exe" extension in its name, which is very common on Windows,
ScanDirForExecutable won't find it under the toolchain-provided paths.

This patch changes the Windows version of the "`can_execute`" function
called by ScanDirForExecutable to respect file extensions, similarly to
llvm::sys::findProgramByName.

Patch by Oleg Ranevskyy

Reviewers: rnk

Differential Revision: http://reviews.llvm.org/D12711

llvm-svn: 247358

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index a77efcca8f5..93e5654f284 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -325,6 +325,10 @@ std::error_code access(const Twine &Path, AccessMode Mode) {
   return std::error_code();
 }
 
+bool can_execute(const Twine &Path) {
+  return !access(Path, AccessMode::Execute);
+}
+
 bool equivalent(file_status A, file_status B) {
   assert(status_known(A) && status_known(B));
   return A.fs_st_dev == B.fs_st_dev &&