Attempt 3: Resubmit "[Support] Expose flattenWindowsCommandLine."

I took some liberties and quoted fewer characters than before,
based on an article from MSDN which says that only certain characters
cause an arg to require quoting.  This seems to be incorrect, though,
and worse it seems to be a difference in Windows version.  The bot
that fails is Windows 7, and I can't reproduce the failure on Win
10.  But it's definitely related to quoting and special characters,
because both tests that fail have a * in the argument, which is one
of the special characters that would cause an argument to be quoted
before but not any longer after the new patch.

Since I don't have Win 7, all I can do is just guess that I need to
restore the old quoting rules.  So this patch does that in hopes that
it fixes the problem on Windows 7.

llvm-svn: 334375

1 files changed, 4 insertions, 6 deletions

diff --git a/llvm/lib/Support/Unix/Program.inc b/llvm/lib/Support/Unix/Program.inc
index 04840bf4448..be971555b82 100644
--- a/llvm/lib/Support/Unix/Program.inc
+++ b/llvm/lib/Support/Unix/Program.inc
@@ -434,7 +434,7 @@ llvm::sys::writeFileWithEncoding(StringRef FileName, StringRef Contents,
 }
 
 bool llvm::sys::commandLineFitsWithinSystemLimits(StringRef Program,
-                                                  ArrayRef<const char *> Args) {
+                                                  ArrayRef<StringRef> Args) {
   static long ArgMax = sysconf(_SC_ARG_MAX);
   // POSIX requires that _POSIX_ARG_MAX is 4096, which is the lowest possible
   // value for ARG_MAX on a POSIX compliant system.
@@ -456,18 +456,16 @@ bool llvm::sys::commandLineFitsWithinSystemLimits(StringRef Program,
   long HalfArgMax = EffectiveArgMax / 2;
 
   size_t ArgLength = Program.size() + 1;
-  for (const char* Arg : Args) {
-    size_t length = strlen(Arg);
-
+  for (StringRef Arg : Args) {
     // Ensure that we do not exceed the MAX_ARG_STRLEN constant on Linux, which
     // does not have a constant unlike what the man pages would have you
     // believe. Since this limit is pretty high, perform the check
     // unconditionally rather than trying to be aggressive and limiting it to
     // Linux only.
-    if (length >= (32 * 4096))
+    if (Arg.size() >= (32 * 4096))
       return false;
 
-    ArgLength += length + 1;
+    ArgLength += Arg.size() + 1;
     if (ArgLength > size_t(HalfArgMax)) {
       return false;
     }