1 files changed, 18 insertions, 16 deletions

diff --git a/lib/Driver/Driver.cpp b/lib/Driver/Driver.cpp
index 8cca1de0fb2b..0f3ebef2cf2f 100644
--- a/lib/Driver/Driver.cpp
+++ b/lib/Driver/Driver.cpp
@@ -277,7 +277,8 @@ DerivedArgList *Driver::TranslateInputArgs(const InputArgList &Args) const {
   // Add a default value of -mlinker-version=, if one was given and the user
   // didn't specify one.
 #if defined(HOST_LINK_VERSION)
-  if (!Args.hasArg(options::OPT_mlinker_version_EQ)) {
+  if (!Args.hasArg(options::OPT_mlinker_version_EQ) &&
+      strlen(HOST_LINK_VERSION) > 0) {
     DAL->AddJoinedArg(0, Opts->getOption(options::OPT_mlinker_version_EQ),
                       HOST_LINK_VERSION);
     DAL->getLastArg(options::OPT_mlinker_version_EQ)->claim();
@@ -814,9 +815,12 @@ bool Driver::HandleImmediateArgs(const Compilation &C) {
   return true;
 }
 
+// Display an action graph human-readably.  Action A is the "sink" node
+// and latest-occuring action. Traversal is in pre-order, visiting the
+// inputs to each action before printing the action itself.
 static unsigned PrintActions1(const Compilation &C, Action *A,
                               std::map<Action*, unsigned> &Ids) {
-  if (Ids.count(A))
+  if (Ids.count(A)) // A was already visited.
     return Ids[A];
 
   std::string str;
@@ -847,6 +851,8 @@ static unsigned PrintActions1(const Compilation &C, Action *A,
   return Id;
 }
 
+// Print the action graphs in a compilation C.
+// For example "clang -c file1.c file2.c" is composed of two subgraphs.
 void Driver::PrintActions(const Compilation &C) const {
   std::map<Action*, unsigned> Ids;
   for (ActionList::const_iterator it = C.getActions().begin(),
@@ -1356,7 +1362,7 @@ Driver::ConstructPhaseAction(const ToolChain &TC, const ArgList &Args,
                                                types::TY_LLVM_BC);
   }
   case phases::Backend: {
-    if (IsUsingLTO(TC, Args)) {
+    if (IsUsingLTO(Args)) {
       types::ID Output =
         Args.hasArg(options::OPT_S) ? types::TY_LTO_IR : types::TY_LTO_BC;
       return llvm::make_unique<BackendJobAction>(std::move(Input), Output);
@@ -1377,14 +1383,8 @@ Driver::ConstructPhaseAction(const ToolChain &TC, const ArgList &Args,
   llvm_unreachable("invalid phase in ConstructPhaseAction");
 }
 
-bool Driver::IsUsingLTO(const ToolChain &TC, const ArgList &Args) const {
-  if (TC.getSanitizerArgs().needsLTO())
-    return true;
-
-  if (Args.hasFlag(options::OPT_flto, options::OPT_fno_lto, false))
-    return true;
-
-  return false;
+bool Driver::IsUsingLTO(const ArgList &Args) const {
+  return Args.hasFlag(options::OPT_flto, options::OPT_fno_lto, false);
 }
 
 void Driver::BuildJobs(Compilation &C) const {
@@ -1563,8 +1563,9 @@ void Driver::BuildJobsForAction(Compilation &C,
     if (Input.getOption().matches(options::OPT_INPUT)) {
       const char *Name = Input.getValue();
       Result = InputInfo(Name, A->getType(), Name);
-    } else
+    } else {
       Result = InputInfo(&Input, A->getType(), "");
+    }
     return;
   }
 
@@ -1738,7 +1739,7 @@ const char *Driver::GetNamedOutputPath(Compilation &C,
   // Determine what the derived output name should be.
   const char *NamedOutput;
 
-  if ((JA.getType() == types::TY_Object || JA.getType() == types::TY_LTO_BC) &&
+  if (JA.getType() == types::TY_Object &&
       C.getArgs().hasArg(options::OPT__SLASH_Fo, options::OPT__SLASH_o)) {
     // The /Fo or /o flag decides the object filename.
     StringRef Val = C.getArgs().getLastArg(options::OPT__SLASH_Fo,
@@ -2099,6 +2100,8 @@ const ToolChain &Driver::getToolChain(const ArgList &Args,
         TC = new toolchains::Hexagon_TC(*this, Target, Args);
       else if (Target.getArch() == llvm::Triple::xcore)
         TC = new toolchains::XCore(*this, Target, Args);
+      else if (Target.getArch() == llvm::Triple::shave)
+        TC = new toolchains::SHAVEToolChain(*this, Target, Args);
       else if (Target.isOSBinFormatELF())
         TC = new toolchains::Generic_ELF(*this, Target, Args);
       else if (Target.isOSBinFormatMachO())
@@ -2112,13 +2115,12 @@ const ToolChain &Driver::getToolChain(const ArgList &Args,
 }
 
 bool Driver::ShouldUseClangCompiler(const JobAction &JA) const {
-  // Check if user requested no clang, or clang doesn't understand this type (we
-  // only handle single inputs for now).
+  // Say "no" if there is not exactly one input of a type clang understands.
   if (JA.size() != 1 ||
       !types::isAcceptedByClang((*JA.begin())->getType()))
     return false;
 
-  // Otherwise make sure this is an action clang understands.
+  // And say "no" if this is not a kind of action clang understands.
   if (!isa<PreprocessJobAction>(JA) && !isa<PrecompileJobAction>(JA) &&
       !isa<CompileJobAction>(JA) && !isa<BackendJobAction>(JA))
     return false;