[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

2 files changed, 60 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;
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index c6a5bc74145..7d3793e2fd6 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -5126,6 +5126,32 @@ static void handleAnyX86InterruptAttr(Sema &S, Decl *D,
   D->addAttr(UsedAttr::CreateImplicit(S.Context));
 }
 
+static void handleAVRInterruptAttr(Sema &S, Decl *D, const AttributeList &Attr) {
+  if (!isFunctionOrMethod(D)) {
+    S.Diag(D->getLocation(), diag::warn_attribute_wrong_decl_type)
+        << "'interrupt'" << ExpectedFunction;
+    return;
+  }
+
+  if (!checkAttributeNumArgs(S, Attr, 0))
+    return;
+
+  handleSimpleAttribute<AVRInterruptAttr>(S, D, Attr);
+}
+
+static void handleAVRSignalAttr(Sema &S, Decl *D, const AttributeList &Attr) {
+  if (!isFunctionOrMethod(D)) {
+    S.Diag(D->getLocation(), diag::warn_attribute_wrong_decl_type)
+        << "'signal'" << ExpectedFunction;
+    return;
+  }
+
+  if (!checkAttributeNumArgs(S, Attr, 0))
+    return;
+
+  handleSimpleAttribute<AVRSignalAttr>(S, D, Attr);
+}
+
 static void handleInterruptAttr(Sema &S, Decl *D, const AttributeList &Attr) {
   // Dispatch the interrupt attribute based on the current target.
   switch (S.Context.getTargetInfo().getTriple().getArch()) {
@@ -5140,6 +5166,9 @@ static void handleInterruptAttr(Sema &S, Decl *D, const AttributeList &Attr) {
   case llvm::Triple::x86_64:
     handleAnyX86InterruptAttr(S, D, Attr);
     break;
+  case llvm::Triple::avr:
+    handleAVRInterruptAttr(S, D, Attr);
+    break;
   default:
     handleARMInterruptAttr(S, D, Attr);
     break;
@@ -5700,6 +5729,9 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
   case AttributeList::AT_AMDGPUNumVGPR:
     handleAMDGPUNumVGPRAttr(S, D, Attr);
     break;
+  case AttributeList::AT_AVRSignal:
+    handleAVRSignalAttr(S, D, Attr);
+    break;
   case AttributeList::AT_IBAction:
     handleSimpleAttribute<IBActionAttr>(S, D, Attr);
     break;