Re: [PATCH] D20454: Eliminate unnecessary file access checks in Clang driver on Windows

[Adrian McCarthy via cfe-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL270226: Eliminate unnecessary file access checks in Clang 
driver on Windows (authored by amccarth).

Changed prior to commit:
  http://reviews.llvm.org/D20454?vs=57872&id=57936#toc

Repository:
  rL LLVM

http://reviews.llvm.org/D20454

Files:
  cfe/trunk/lib/Driver/MSVCToolChain.cpp

Index: cfe/trunk/lib/Driver/MSVCToolChain.cpp
===
--- cfe/trunk/lib/Driver/MSVCToolChain.cpp
+++ cfe/trunk/lib/Driver/MSVCToolChain.cpp
@@ -408,7 +408,10 @@
 
 SmallString<128> FilePath(PathSegment);
 llvm::sys::path::append(FilePath, "cl.exe");
-if (llvm::sys::fs::can_execute(FilePath.c_str()) &&
+// Checking if cl.exe exists is a small optimization over calling
+// can_execute, which really only checks for existence but will also do
+// extra checks for cl.exe.exe.  These add up when walking a long path.
+if (llvm::sys::fs::exists(FilePath.c_str()) &&
 !llvm::sys::fs::equivalent(FilePath.c_str(), clangProgramPath)) {
   // If we found it on the PATH, use it exactly as is with no
   // modifications.


Index: cfe/trunk/lib/Driver/MSVCToolChain.cpp
===
--- cfe/trunk/lib/Driver/MSVCToolChain.cpp
+++ cfe/trunk/lib/Driver/MSVCToolChain.cpp
@@ -408,7 +408,10 @@
 
 SmallString<128> FilePath(PathSegment);
 llvm::sys::path::append(FilePath, "cl.exe");
-if (llvm::sys::fs::can_execute(FilePath.c_str()) &&
+// Checking if cl.exe exists is a small optimization over calling
+// can_execute, which really only checks for existence but will also do
+// extra checks for cl.exe.exe.  These add up when walking a long path.
+if (llvm::sys::fs::exists(FilePath.c_str()) &&
 !llvm::sys::fs::equivalent(FilePath.c_str(), clangProgramPath)) {
   // If we found it on the PATH, use it exactly as is with no
   // modifications.
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Re: [PATCH] D20454: Eliminate unnecessary file access checks in Clang driver on Windows

[David Majnemer via cfe-commits]

majnemer accepted this revision.
majnemer added a comment.
This revision is now accepted and ready to land.

LGTM


http://reviews.llvm.org/D20454



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[PATCH] D20454: Eliminate unnecessary file access checks in Clang driver on Windows

[Adrian McCarthy via cfe-commits]

amccarth created this revision.
amccarth added a reviewer: majnemer.
amccarth added a subscriber: cfe-commits.

This fixes the problem where the driver will look for cl.exe.exe while walking 
the PATH.

I looked into changing the Windows implementation of 
llvm::sys::fs::can_execute(), but there wasn't a satisfying way to preserve the 
extra checks for the callers that depend on it.  I also looked into having it 
actually check that the file is an executable, but this seemed to add little 
value at the cost of more file i/o.

http://reviews.llvm.org/D20454

Files:
  lib/Driver/MSVCToolChain.cpp

Index: lib/Driver/MSVCToolChain.cpp
===
--- lib/Driver/MSVCToolChain.cpp
+++ lib/Driver/MSVCToolChain.cpp
@@ -408,7 +408,10 @@
 
 SmallString<128> FilePath(PathSegment);
 llvm::sys::path::append(FilePath, "cl.exe");
-if (llvm::sys::fs::can_execute(FilePath.c_str()) &&
+// Checking if cl.exe exists is a small optimization over calling
+// can_execute, which really only checks for existence but will also do
+// extra checks for cl.exe.exe.  These add up when walking a long path.
+if (llvm::sys::fs::exists(FilePath.c_str()) &&
 !llvm::sys::fs::equivalent(FilePath.c_str(), clangProgramPath)) {
   // If we found it on the PATH, use it exactly as is with no
   // modifications.


Index: lib/Driver/MSVCToolChain.cpp
===
--- lib/Driver/MSVCToolChain.cpp
+++ lib/Driver/MSVCToolChain.cpp
@@ -408,7 +408,10 @@
 
 SmallString<128> FilePath(PathSegment);
 llvm::sys::path::append(FilePath, "cl.exe");
-if (llvm::sys::fs::can_execute(FilePath.c_str()) &&
+// Checking if cl.exe exists is a small optimization over calling
+// can_execute, which really only checks for existence but will also do
+// extra checks for cl.exe.exe.  These add up when walking a long path.
+if (llvm::sys::fs::exists(FilePath.c_str()) &&
 !llvm::sys::fs::equivalent(FilePath.c_str(), clangProgramPath)) {
   // If we found it on the PATH, use it exactly as is with no
   // modifications.
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