Start hoisting the logic for computing the target triple into its own

function. The logic for this, and I want to emphasize that this is the
logic for computing the *target* triple, is currently scattered
throughout various different HostInfo classes ToolChain factoring
functions. Best part, it is largely *duplicated* there. The goal is to
hoist all of that up to here where we can deal with it once, and in
a consistent manner.

Unfortunately, this uncovers more fun problems: the ToolChains assume
that the *actual* target triple is the one passed into them by these
factory functions, while the *host* triple is the one in the driver.
This already was a lie, and a damn lie, when the '-target' flag was
specified. It only really worked when the difference stemmed from '-m32'
and '-m64' flags. I'll have to fix that (and remove all the FIXMEs I've
introduced here to document the problem) before I can finish hoisting
the target-calculation logic.

It's bugs all the way down today it seems...

llvm-svn: 148839

1 files changed, 14 insertions, 8 deletions

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index c5007b820f9..217df02b7fd 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -237,6 +237,18 @@ DerivedArgList *Driver::TranslateInputArgs(const InputArgList &Args) const {
   return DAL;
 }
 
+/// \brief Compute target triple from args.
+///
+/// This routine provides the logic to compute a target triple from various
+/// args passed to the driver and the default triple string.
+static llvm::Triple computeTargetTriple(StringRef DefaultTargetTriple,
+                                        const ArgList &Args) {
+  if (const Arg *A = Args.getLastArg(options::OPT_target))
+    DefaultTargetTriple = A->getValue(Args);
+
+  return llvm::Triple(llvm::Triple::normalize(DefaultTargetTriple));
+}
+
 Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
   llvm::PrettyStackTraceString CrashInfo("Compilation construction");
 
@@ -305,10 +317,6 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
       Cur = Split.second;
     }
   }
-  // FIXME: We shouldn't overwrite the default host triple here, but we have
-  // nowhere else to put this currently.
-  if (const Arg *A = Args->getLastArg(options::OPT_target))
-    DefaultTargetTriple = A->getValue(*Args);
   if (const Arg *A = Args->getLastArg(options::OPT_ccc_install_dir))
     Dir = InstalledDir = A->getValue(*Args);
   for (arg_iterator it = Args->filtered_begin(options::OPT_B),
@@ -322,10 +330,8 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
   if (Args->hasArg(options::OPT_nostdlib))
     UseStdLib = false;
 
-  // Reset the target triple here as we may have adjusted the
-  // DefaultTargetTriple string for flags above.
-  // FIXME: Same fix is needed here when the above flag management is fixed.
-  TargetTriple = llvm::Triple(llvm::Triple::normalize(DefaultTargetTriple));
+  // Recompute the target triple based on the args.
+  TargetTriple = computeTargetTriple(DefaultTargetTriple, *Args);
   Host = GetHostInfo(TargetTriple);
 
   // Perform the default argument translations.