[AVR] Add support for the 'interrupt' and 'naked' attributes

Summary:
This teaches clang how to parse and lower the 'interrupt' and 'naked'
attributes.

This allows interrupt signal handlers to be written.

Reviewers: aaron.ballman

Subscribers: malcolm.parsons, cfe-commits

Differential Revision: https://reviews.llvm.org/D28451

llvm-svn: 294402

1 files changed, 28 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index f0a27f9d560..19b63ce6213 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -6900,6 +6900,31 @@ MIPSTargetCodeGenInfo::initDwarfEHRegSizeTable(CodeGen::CodeGenFunction &CGF,
 }
 
 //===----------------------------------------------------------------------===//
+// AVR ABI Implementation.
+//===----------------------------------------------------------------------===//
+
+namespace {
+class AVRTargetCodeGenInfo : public TargetCodeGenInfo {
+public:
+  AVRTargetCodeGenInfo(CodeGenTypes &CGT)
+    : TargetCodeGenInfo(new DefaultABIInfo(CGT)) { }
+
+  void setTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
+                           CodeGen::CodeGenModule &CGM) const override {
+    const auto *FD = dyn_cast_or_null<FunctionDecl>(D);
+    if (!FD) return;
+    auto *Fn = cast<llvm::Function>(GV);
+
+    if (FD->getAttr<AVRInterruptAttr>())
+      Fn->addFnAttr("interrupt");
+
+    if (FD->getAttr<AVRSignalAttr>())
+      Fn->addFnAttr("signal");
+  }
+};
+}
+
+//===----------------------------------------------------------------------===//
 // TCE ABI Implementation (see http://tce.cs.tut.fi). Uses mostly the defaults.
 // Currently subclassed only to implement custom OpenCL C function attribute
 // handling.
@@ -8402,6 +8427,9 @@ const TargetCodeGenInfo &CodeGenModule::getTargetCodeGenInfo() {
   case llvm::Triple::mips64el:
     return SetCGInfo(new MIPSTargetCodeGenInfo(Types, false));
 
+  case llvm::Triple::avr:
+    return SetCGInfo(new AVRTargetCodeGenInfo(Types));
+
   case llvm::Triple::aarch64:
   case llvm::Triple::aarch64_be: {
     AArch64ABIInfo::ABIKind Kind = AArch64ABIInfo::AAPCS;