[PATCH] [Support][Program] Add findProgramByName(Name, OptionalPaths)

[Michael Spencer]

================
Comment at: lib/Support/Unix/Program.inc:107
@@ +106,3 @@
+  // Check some degenerate cases
+  if (Name.empty()) // no program
+    return std::errc::no_such_file_or_directory;
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rafael wrote:
> assert
K.

================
Comment at: lib/Support/Unix/Program.inc:116
@@ +115,3 @@
+    SmallVector<StringRef, 16> SearchPaths;
+    SplitString(std::getenv("PATH"), SearchPaths, ":");
+    return findProgramByName(Name, SearchPaths);
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rafael wrote:
> on windows it is ; instead of :, no.
This is UNIX only code.

================
Comment at: lib/Support/Unix/Program.inc:120
@@ +119,3 @@
+
+  if (Paths.empty())
+    return std::errc::no_such_file_or_directory;
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rafael wrote:
> Redundant if. Just let the for iterate 0 times.
K.

================
Comment at: lib/Support/Unix/Program.inc:130
@@ +129,3 @@
+    sys::path::append(FilePath, Name);
+    if (sys::fs::can_execute(Twine(FilePath)))
+      return std::string(FilePath.str()); // Found the executable!
----------------
rafael wrote:
> .c_str() since we have a SmallString anyway.
K.

http://reviews.llvm.org/D6067