[MSP430] Improve support of 'interrupt' attribute

* Accept as an argument constants in range 0..63 (aligned with TI headers and linker scripts provided with TI GCC toolchain).
* Emit function attribute 'interrupt'='xx' instead of aliases (used in the backend to create a section for particular interrupt vector).
* Add more diagnostics.

Patch by Kristina Bessonova!

Differential Revision: https://reviews.llvm.org/D56663

llvm-svn: 351344

2 files changed, 33 insertions, 16 deletions

diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 89ec73670a7..f5a770ed9d8 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -6774,21 +6774,19 @@ void MSP430TargetCodeGenInfo::setTargetAttributes(
   if (GV->isDeclaration())
     return;
   if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) {
-    if (const MSP430InterruptAttr *attr = FD->getAttr<MSP430InterruptAttr>()) {
-      // Handle 'interrupt' attribute:
-      llvm::Function *F = cast<llvm::Function>(GV);
+    const auto *InterruptAttr = FD->getAttr<MSP430InterruptAttr>();
+    if (!InterruptAttr)
+      return;
 
-      // Step 1: Set ISR calling convention.
-      F->setCallingConv(llvm::CallingConv::MSP430_INTR);
+    // Handle 'interrupt' attribute:
+    llvm::Function *F = cast<llvm::Function>(GV);
 
-      // Step 2: Add attributes goodness.
-      F->addFnAttr(llvm::Attribute::NoInline);
+    // Step 1: Set ISR calling convention.
+    F->setCallingConv(llvm::CallingConv::MSP430_INTR);
 
-      // Step 3: Emit ISR vector alias.
-      unsigned Num = attr->getNumber() / 2;
-      llvm::GlobalAlias::create(llvm::Function::ExternalLinkage,
-                                "__isr_" + Twine(Num), F);
-    }
+    // Step 2: Add attributes goodness.
+    F->addFnAttr(llvm::Attribute::NoInline);
+    F->addFnAttr("interrupt", llvm::utostr(InterruptAttr->getNumber()));
   }
 }
 
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 0e10804a2ec..eb95cc748b1 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -5377,6 +5377,27 @@ static void handleARMInterruptAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
 }
 
 static void handleMSP430InterruptAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+  // MSP430 'interrupt' attribute is applied to
+  // a function with no parameters and void return type.
+  if (!isFunctionOrMethod(D)) {
+    S.Diag(D->getLocation(), diag::warn_attribute_wrong_decl_type)
+        << "'interrupt'" << ExpectedFunctionOrMethod;
+    return;
+  }
+
+  if (hasFunctionProto(D) && getFunctionOrMethodNumParams(D) != 0) {
+    S.Diag(D->getLocation(), diag::warn_msp430_interrupt_attribute)
+        << 0;
+    return;
+  }
+
+  if (!getFunctionOrMethodResultType(D)->isVoidType()) {
+    S.Diag(D->getLocation(), diag::warn_msp430_interrupt_attribute)
+        << 1;
+    return;
+  }
+
+  // The attribute takes one integer argument.
   if (!checkAttributeNumArgs(S, AL, 1))
     return;
 
@@ -5386,8 +5407,6 @@ static void handleMSP430InterruptAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
     return;
   }
 
-  // FIXME: Check for decl - it should be void ()(void).
-
   Expr *NumParamsExpr = static_cast<Expr *>(AL.getArgAsExpr(0));
   llvm::APSInt NumParams(32);
   if (!NumParamsExpr->isIntegerConstantExpr(NumParams, S.Context)) {
@@ -5396,9 +5415,9 @@ static void handleMSP430InterruptAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
         << NumParamsExpr->getSourceRange();
     return;
   }
-
+  // The argument should be in range 0..63.
   unsigned Num = NumParams.getLimitedValue(255);
-  if ((Num & 1) || Num > 30) {
+  if (Num > 63) {
     S.Diag(AL.getLoc(), diag::err_attribute_argument_out_of_bounds)
         << AL << (int)NumParams.getSExtValue()
         << NumParamsExpr->getSourceRange();