Refactor ExecuteAndWait to take StringRefs.

This simplifies some code which had StringRefs to begin with, and
makes other code more complicated which had const char* to begin
with.

In the end, I think this makes for a more idiomatic and platform
agnostic API.  Not all platforms launch process with null terminated
c-string arrays for the environment pointer and argv, but the api
was designed that way because it allowed easy pass-through for
posix-based platforms.  There's a little additional overhead now
since on posix based platforms we'll be takign StringRefs which
were constructed from null terminated strings and then copying
them to null terminate them again, but from a readability and
usability standpoint of the API user, I think this API signature
is strictly better.

llvm-svn: 334518

1 files changed, 7 insertions, 14 deletions

diff --git a/llvm/lib/Support/Windows/Program.inc b/llvm/lib/Support/Windows/Program.inc
index 19a38c78432..cb68c5b10e5 100644
--- a/llvm/lib/Support/Windows/Program.inc
+++ b/llvm/lib/Support/Windows/Program.inc
@@ -149,15 +149,9 @@ static HANDLE RedirectIO(Optional<StringRef> Path, int fd,
 
 }
 
-static SmallVector<StringRef, 8> buildArgVector(const char **Args) {
-  SmallVector<StringRef, 8> Result;
-  for (unsigned I = 0; Args[I]; ++I)
-    Result.push_back(StringRef(Args[I]));
-  return Result;
-}
-
-static bool Execute(ProcessInfo &PI, StringRef Program, const char **Args,
-                    const char **Envp, ArrayRef<Optional<StringRef>> Redirects,
+static bool Execute(ProcessInfo &PI, StringRef Program,
+                    ArrayRef<StringRef> Args, Optional<ArrayRef<StringRef>> Env,
+                    ArrayRef<Optional<StringRef>> Redirects,
                     unsigned MemoryLimit, std::string *ErrMsg) {
   if (!sys::fs::can_execute(Program)) {
     if (ErrMsg)
@@ -176,19 +170,18 @@ static bool Execute(ProcessInfo &PI, StringRef Program, const char **Args,
   // Windows wants a command line, not an array of args, to pass to the new
   // process.  We have to concatenate them all, while quoting the args that
   // have embedded spaces (or are empty).
-  auto ArgVector = buildArgVector(Args);
-  std::string Command = flattenWindowsCommandLine(ArgVector);
+  std::string Command = flattenWindowsCommandLine(Args);
 
   // The pointer to the environment block for the new process.
   std::vector<wchar_t> EnvBlock;
 
-  if (Envp) {
+  if (Env) {
     // An environment block consists of a null-terminated block of
     // null-terminated strings. Convert the array of environment variables to
     // an environment block by concatenating them.
-    for (unsigned i = 0; Envp[i]; ++i) {
+    for (const auto E : *Env) {
       SmallVector<wchar_t, MAX_PATH> EnvString;
-      if (std::error_code ec = windows::UTF8ToUTF16(Envp[i], EnvString)) {
+      if (std::error_code ec = windows::UTF8ToUTF16(E, EnvString)) {
         SetLastError(ec.value());
         MakeErrMsg(ErrMsg, "Unable to convert environment variable to UTF-16");
         return false;