Roll back r82348, which introduced an infinite loop in ParseCStringVector() that

a trivial unittest would have caught.  This revision also adds the trivial
unittest.

llvm-svn: 82675

1 files changed, 33 insertions, 22 deletions

diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
index 43686c07cce..204145396e4 100644
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -351,31 +351,42 @@ static bool EatsUnboundedNumberOfValues(const Option *O) {
 /// using strdup(), so it is the caller's responsibility to free()
 /// them later.
 ///
-static void ParseCStringVector(std::vector<char *> &OutputVector,
-                               const char *Input) {
+static void ParseCStringVector(std::vector<char *> &output,
+                               const char *input) {
   // Characters which will be treated as token separators:
-  StringRef Delims = " \v\f\t\r\n";
-
-  StringRef WorkStr(Input);
-  while (!WorkStr.empty()) {
-    // If the first character is a delimiter, strip them off.
-    if (Delims.find(WorkStr[0]) != StringRef::npos) {
-      size_t Pos = WorkStr.find_first_not_of(Delims);
-      if (Pos == StringRef::npos) Pos = WorkStr.size();
-      WorkStr = WorkStr.substr(Pos);
-      continue;
+  static const char *const delims = " \v\f\t\r\n";
+
+  std::string work(input);
+  // Skip past any delims at head of input string.
+  size_t pos = work.find_first_not_of(delims);
+  // If the string consists entirely of delims, then exit early.
+  if (pos == std::string::npos) return;
+  // Otherwise, jump forward to beginning of first word.
+  work = work.substr(pos);
+  // Find position of first delimiter.
+  pos = work.find_first_of(delims);
+
+  while (!work.empty() && pos != std::string::npos) {
+    // Everything from 0 to POS is the next word to copy.
+    output.push_back(strdup(work.substr(0,pos).c_str()));
+    // Is there another word in the string?
+    size_t nextpos = work.find_first_not_of(delims, pos + 1);
+    if (nextpos != std::string::npos) {
+      // Yes? Then remove delims from beginning ...
+      work = work.substr(work.find_first_not_of(delims, pos + 1));
+      // and find the end of the word.
+      pos = work.find_first_of(delims);
+    } else {
+      // No? (Remainder of string is delims.) End the loop.
+      work = "";
+      pos = std::string::npos;
     }
-    
-    // Find position of first delimiter.
-    size_t Pos = WorkStr.find_first_of(Delims);
-    if (Pos == StringRef::npos) Pos = WorkStr.size();
-    
-    // Everything from 0 to Pos is the next word to copy.
-    char *NewStr = (char*)malloc(Pos+1);
-    memcpy(NewStr, WorkStr.data(), Pos);
-    NewStr[Pos] = 0;
-    OutputVector.push_back(NewStr);
   }
+
+  // If `input' ended with non-delim char, then we'll get here with
+  // the last word of `input' in `work'; copy it now.
+  if (!work.empty())
+    output.push_back(strdup(work.c_str()));
 }
 
 /// ParseEnvironmentOptions - An alternative entry point to the