From 5f18f6e4d684d57b8f2430e5199e60a31ef78db0 Mon Sep 17 00:00:00 2001
From: Daniel Dunbar <daniel@zuster.org>
Date: Mon, 22 Oct 2012 18:30:51 +0000
Subject: [PATCH] driver/Darwin: Default to AAPCS for M-class CPUs.

 - This is an assumption that is currently hardwired into the backend, we need
   to do this in order for the frontend and backend to agree.

llvm-svn: 166428
---
 clang/lib/Driver/Tools.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index edaa1dbefeec..7848b488d37b 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -683,6 +683,7 @@ void Clang::AddARMTargetArgs(const ArgList &Args,
   // Get the effective triple, which takes into account the deployment target.
   std::string TripleStr = getToolChain().ComputeEffectiveClangTriple(Args);
   llvm::Triple Triple(TripleStr);
+  std::string CPUName = getARMTargetCPU(Args, Triple);
 
   // Select the ABI to use.
   //
@@ -690,6 +691,14 @@ void Clang::AddARMTargetArgs(const ArgList &Args,
   const char *ABIName = 0;
   if (Arg *A = Args.getLastArg(options::OPT_mabi_EQ)) {
     ABIName = A->getValue(Args);
+  } else if (Triple.isOSDarwin()) {
+    // The backend is hardwired to assume AAPCS for M-class processors, ensure
+    // the frontend matches that.
+    if (StringRef(CPUName).startswith("cortex-m")) {
+      ABIName = "aapcs";
+    } else {
+      ABIName = "apcs-gnu";
+    }
   } else {
     // Select the default based on the platform.
     switch(Triple.getEnvironment()) {
@@ -710,7 +719,7 @@ void Clang::AddARMTargetArgs(const ArgList &Args,
 
   // Set the CPU based on -march= and -mcpu=.
   CmdArgs.push_back("-target-cpu");
-  CmdArgs.push_back(Args.MakeArgString(getARMTargetCPU(Args, Triple)));
+  CmdArgs.push_back(Args.MakeArgString(CPUName));
 
   // Determine floating point ABI from the options & target defaults.
   StringRef FloatABI = getARMFloatABI(D, Args, Triple);