Fix PR17239 by changing the semantics of the RemainingArgsClass Option kind

This patch aims at fixing PR17239.

This bug happens because the /link (clang-cl.exe argument) is marked as
"consume all remaining arguments". However, when inside a response file,
/link should only consume all remaining arguments inside the response
file where it is located, not the entire command line after expansion.
The LLVM side of the patch will change the semantics of the
RemainingArgsClass kind to always consume only until the end of the
response file when the option originally came from a response file.
There are only two options in this class: dash dash (--) and /link.

This is the Clang side of the patch in http://reviews.llvm.org/D4899

Reviewered By: rafael, rnk

Differential Revision: http://reviews.llvm.org/D4900

Patch by Rafael Auler!

llvm-svn: 216281

clang/lib/Driver/Driver.cpp

@@ -83,6 +83,9 @@ void Driver::ParseDriverMode(ArrayRef<const char *> Args) {
     getOpts().getOption(options::OPT_driver_mode).getPrefixedName();
 
   for (size_t I = 0, E = Args.size(); I != E; ++I) {
+    // Ingore nullptrs, they are response file's EOL markers
+    if (Args[I] == nullptr)
+      continue;
     const StringRef Arg = Args[I];
     if (!Arg.startswith(OptName))
       continue;
@@ -102,7 +105,7 @@ void Driver::ParseDriverMode(ArrayRef<const char *> Args) {
   }
 }
 
-InputArgList *Driver::ParseArgStrings(ArrayRef<const char *> ArgList) {
+InputArgList *Driver::ParseArgStrings(ArrayRef<const char *> ArgStrings) {
   llvm::PrettyStackTraceString CrashInfo("Command line argument parsing");
 
   unsigned IncludedFlagsBitmask;
@@ -111,7 +114,7 @@ InputArgList *Driver::ParseArgStrings(ArrayRef<const char *> ArgList) {
     getIncludeExcludeOptionFlagMasks();
 
   unsigned MissingArgIndex, MissingArgCount;
-  InputArgList *Args = getOpts().ParseArgs(ArgList.begin(), ArgList.end(),
+  InputArgList *Args = getOpts().ParseArgs(ArgStrings.begin(), ArgStrings.end(),
                                            MissingArgIndex, MissingArgCount,
                                            IncludedFlagsBitmask,
                                            ExcludedFlagsBitmask);

clang/test/Driver/Inputs/cc1-response.txt

@@ -0,0 +1,4 @@
+
+
+-cc1
+-triple i686-pc-windows-msvc

clang/test/Driver/cc1-response-files.c

@@ -0,0 +1,2 @@
+// RUN: %clang @%S/Inputs/cc1-response.txt -fsyntax-only -disable-llvm-optzns
+int main() {}

clang/test/Driver/cl-link-at-file.c

@@ -0,0 +1,22 @@
+// PR17239 - The /link option, when inside a response file, should only extend
+// until the end of the response file (and not the entire command line)
+
+// Don't attempt slash switches on msys bash.
+// REQUIRES: shell-preserves-root
+
+// Note: %s must be preceded by -- or bound to another option, otherwise it may
+// be interpreted as a command-line option, e.g. on Mac where %s is commonly
+// under /Users.
+
+// RUN: echo /link bar.lib baz.lib > %t.args
+// RUN: touch %t.obj
+// RUN: %clang_cl -### @%t.args -- %t.obj 2>&1 | FileCheck %s -check-prefix=ARGS
+// If the "/link" option captures all remaining args beyond its response file,
+// it will also capture "--" and our input argument. In this case, Clang will
+// be clueless and will emit "argument unused" warnings. If PR17239 is properly
+// fixed, this should not happen because the "/link" option is restricted to
+// consume only remaining args in its response file.
+// ARGS-NOT: warning
+// ARGS-NOT: argument unused during compilation
+// Identify the linker command
+// ARGS: link.exe

clang/tools/driver/driver.cpp

@@ -116,6 +116,9 @@ static void ApplyOneQAOverride(raw_ostream &OS,
     ReplPattern = ReplPattern.slice(0, ReplPattern.size()-1);
 
     for (unsigned i = 1, e = Args.size(); i != e; ++i) {
+      // Ignore end-of-line response file markers
+      if (Args[i] == nullptr)
+        continue;
       std::string Repl = llvm::Regex(MatchPattern).sub(ReplPattern, Args[i]);
 
       if (Repl != Args[i]) {
@@ -142,6 +145,9 @@ static void ApplyOneQAOverride(raw_ostream &OS,
   } else if (Edit[0] == 'O') {
     for (unsigned i = 1; i < Args.size();) {
       const char *A = Args[i];
+      // Ignore end-of-line response file markers
+      if (A == nullptr)
+        continue;
       if (A[0] == '-' && A[1] == 'O' &&
           (A[2] == '\0' ||
            (A[3] == '\0' && (A[2] == 's' || A[2] == 'z' ||
@@ -384,14 +390,33 @@ int main(int argc_, const char **argv_) {
 
   std::set<std::string> SavedStrings;
   StringSetSaver Saver(SavedStrings);
-  llvm::cl::ExpandResponseFiles(Saver, llvm::cl::TokenizeGNUCommandLine, argv);
 
-  // Handle -cc1 integrated tools.
+  // Determines whether we want nullptr markers in argv to indicate response
+  // files end-of-lines. We only use this for the /LINK driver argument.
+  bool MarkEOLs = true;
   if (argv.size() > 1 && StringRef(argv[1]).startswith("-cc1"))
+    MarkEOLs = false;
+  llvm::cl::ExpandResponseFiles(Saver, llvm::cl::TokenizeGNUCommandLine, argv,
+                                MarkEOLs);
+
+  // Handle -cc1 integrated tools, even if -cc1 was expanded from a response
+  // file.
+  auto FirstArg = std::find_if(argv.begin() + 1, argv.end(),
+                               [](const char *A) { return A != nullptr; });
+  if (FirstArg != argv.end() && StringRef(*FirstArg).startswith("-cc1")) {
+    // If -cc1 came from a response file, remove the EOL sentinels.
+    if (MarkEOLs) {
+      auto newEnd = std::remove(argv.begin(), argv.end(), nullptr);
+      argv.resize(newEnd - argv.begin());
+    }
     return ExecuteCC1Tool(argv, argv[1] + 4);
+  }
 
   bool CanonicalPrefixes = true;
   for (int i = 1, size = argv.size(); i < size; ++i) {
+    // Skip end-of-line response file markers
+    if (argv[i] == nullptr)
+      continue;
     if (StringRef(argv[i]) == "-no-canonical-prefixes") {
       CanonicalPrefixes = false;
       break;