[ARM] Error out if float-ab=hard and abi=apcs-gnu on macho platforms.

Error out if -mfloat-abi=hard or -mhard-float is specified on the command
line and the target ABI is APCS. Previously clang issued no warnings or
errors and just passed the option to the backend, which had no effect on
code generation for targets using APCS.

This commit corrects the patch commited in r245866, which didn't take into
account the fact that not all darwin targets use APCS.

rdar://problem/22257950

http://reviews.llvm.org/D12344

llvm-svn: 246054

2 files changed, 21 insertions, 4 deletions

diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index ba5dad5466f..6de6eeb011c 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -563,6 +563,13 @@ static void checkARMCPUName(const Driver &D, const Arg *A, const ArgList &Args,
     D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
 }
 
+static bool useAAPCSForMachO(const llvm::Triple &T) {
+  // The backend is hardwired to assume AAPCS for M-class processors, ensure
+  // the frontend matches that.
+  return T.getEnvironment() == llvm::Triple::EABI ||
+         T.getOS() == llvm::Triple::UnknownOS || isARMMProfile(T);
+}
+
 // Select the float ABI as determined by -msoft-float, -mhard-float, and
 // -mfloat-abi=.
 StringRef tools::arm::getARMFloatABI(const Driver &D, const ArgList &Args,
@@ -582,6 +589,13 @@ StringRef tools::arm::getARMFloatABI(const Driver &D, const ArgList &Args,
         FloatABI = "soft";
       }
     }
+
+    // It is incorrect to select hard float ABI on MachO platforms if the ABI is
+    // "apcs-gnu".
+    if (Triple.isOSBinFormatMachO() && !useAAPCSForMachO(Triple) &&
+        FloatABI == "hard")
+      D.Diag(diag::err_drv_unsupported_opt_for_target) << A->getAsString(Args)
+                                                       << Triple.getArchName();
   }
 
   // If unspecified, choose the default based on the platform.
@@ -856,10 +870,7 @@ void Clang::AddARMTargetArgs(const ArgList &Args, ArgStringList &CmdArgs,
   if (Arg *A = Args.getLastArg(options::OPT_mabi_EQ)) {
     ABIName = A->getValue();
   } else if (Triple.isOSBinFormatMachO()) {
-    // The backend is hardwired to assume AAPCS for M-class processors, ensure
-    // the frontend matches that.
-    if (Triple.getEnvironment() == llvm::Triple::EABI ||
-        Triple.getOS() == llvm::Triple::UnknownOS || isARMMProfile(Triple)) {
+    if (useAAPCSForMachO(Triple)) {
       ABIName = "aapcs";
     } else {
       ABIName = "apcs-gnu";
diff --git a/clang/test/Driver/arm-float-abi.c b/clang/test/Driver/arm-float-abi.c
new file mode 100644
index 00000000000..e5b42c96960
--- /dev/null
+++ b/clang/test/Driver/arm-float-abi.c
@@ -0,0 +1,6 @@
+// RUN: not %clang %s -target armv7-apple-ios -mfloat-abi=hard 2>&1 | FileCheck -check-prefix=ARMV7-ERROR %s
+// RUN: %clang %s -target armv7-apple-ios -mfloat-abi=softfp -### 2>&1 | FileCheck -check-prefix=NOERROR %s
+// RUN: %clang %s -arch armv7 -target thumbv7-apple-darwin-eabi -mfloat-abi=hard -### 2>&1 | FileCheck -check-prefix=NOERROR %s
+
+// ARMV7-ERROR: unsupported option '-mfloat-abi=hard' for target 'thumbv7'
+// NOERROR-NOT: unsupported option