[x86] Front-end part of MCU psABI support

This patch implements two things in front-end for MCU psABI support:

1) "long double type is the same as double."
2) "New predefined C/C++ pre-processor symbols: iamcu and iamcu__.

Differential Revision: http://reviews.llvm.org/D14205

llvm-svn: 251786

3 files changed, 16 insertions, 1 deletions

diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index 2d41d7f3485..70fa6b3f1bf 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -2335,7 +2335,8 @@ class X86TargetInfo : public TargetInfo {
 public:
   X86TargetInfo(const llvm::Triple &Triple) : TargetInfo(Triple) {
     BigEndian = false;
-    LongDoubleFormat = &llvm::APFloat::x87DoubleExtended;
+    LongDoubleFormat = Triple.isOSIAMCU() ? &llvm::APFloat::IEEEdouble
+                                          : &llvm::APFloat::x87DoubleExtended;
   }
   unsigned getFloatEvalMethod() const override {
     // X87 evaluates with 80 bits "long double" precision.
@@ -3370,6 +3371,11 @@ void X86TargetInfo::getTargetDefines(const LangOptions &Opts,
   }
   if (CPU >= CK_i586)
     Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8");
+
+  if (getTriple().isOSIAMCU()) {
+    Builder.defineMacro("__iamcu");
+    Builder.defineMacro("__iamcu__");
+  }
 }
 
 bool X86TargetInfo::hasFeature(StringRef Feature) const {
diff --git a/clang/test/CodeGen/x86_32-arguments-iamcu.c b/clang/test/CodeGen/x86_32-arguments-iamcu.c
index 5b177bf8c63..bac2fb71a08 100644
--- a/clang/test/CodeGen/x86_32-arguments-iamcu.c
+++ b/clang/test/CodeGen/x86_32-arguments-iamcu.c
@@ -56,3 +56,7 @@ st12_t retLargeStruct(int i1, st12_t r) { return r; }
 // insane.
 // CHECK-LABEL: define i32 @varArgs(i32 inreg %i1, ...)
 int varArgs(int i1, ...) { return i1; }
+
+// CHECK-LABEL: define double @longDoubleArg(double %ld1)
+long double longDoubleArg(long double ld1) { return ld1; }
+
diff --git a/clang/test/Preprocessor/elfiamcu-predefines.c b/clang/test/Preprocessor/elfiamcu-predefines.c
new file mode 100644
index 00000000000..af5e40e3c8a
--- /dev/null
+++ b/clang/test/Preprocessor/elfiamcu-predefines.c
@@ -0,0 +1,5 @@
+// RUN: %clang_cc1 -E -dM -triple i586-intel-elfiamcu | FileCheck %s
+
+// CHECK: #define __iamcu
+// CHECK: #define __iamcu__
+