Use the actual ABI-determined C calling convention for runtime

calls and declarations.

LLVM has a default CC determined by the target triple.  This is
not always the actual default CC for the ABI we've been asked to
target, and so we sometimes find ourselves annotating all user
functions with an explicit calling convention.  Since these
calling conventions usually agree for the simple set of argument
types passed to most runtime functions, using the LLVM-default CC
in principle has no effect.  However, the LLVM optimizer goes
into histrionics if it sees this kind of formal CC mismatch,
since it has no concept of CC compatibility.  Therefore, if this
module happens to define the "runtime" function, or got LTO'ed
with such a definition, we can miscompile;  so it's quite
important to get this right.

Defining runtime functions locally is quite common in embedded
applications.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176286 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 79 insertions, 6 deletions

diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 3bcf7d0f50..9f8aa39bc0 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -1894,6 +1894,85 @@ CodeGenFunction::AddObjCARCExceptionMetadata(llvm::Instruction *Inst) {
                       CGM.getNoObjCARCExceptionsMetadata());
 }
 
+/// Emits a call to the given no-arguments nounwind runtime function.
+llvm::CallInst *
+CodeGenFunction::EmitNounwindRuntimeCall(llvm::Value *callee,
+                                         const llvm::Twine &name) {
+  return EmitNounwindRuntimeCall(callee, ArrayRef<llvm::Value*>(), name);
+}
+
+/// Emits a call to the given nounwind runtime function.
+llvm::CallInst *
+CodeGenFunction::EmitNounwindRuntimeCall(llvm::Value *callee,
+                                         ArrayRef<llvm::Value*> args,
+                                         const llvm::Twine &name) {
+  llvm::CallInst *call = EmitRuntimeCall(callee, args, name);
+  call->setDoesNotThrow();
+  return call;
+}
+
+/// Emits a simple call (never an invoke) to the given no-arguments
+/// runtime function.
+llvm::CallInst *
+CodeGenFunction::EmitRuntimeCall(llvm::Value *callee,
+                                 const llvm::Twine &name) {
+  return EmitRuntimeCall(callee, ArrayRef<llvm::Value*>(), name);
+}
+
+/// Emits a simple call (never an invoke) to the given runtime
+/// function.
+llvm::CallInst *
+CodeGenFunction::EmitRuntimeCall(llvm::Value *callee,
+                                 ArrayRef<llvm::Value*> args,
+                                 const llvm::Twine &name) {
+  llvm::CallInst *call = Builder.CreateCall(callee, args, name);
+  call->setCallingConv(getRuntimeCC());
+  return call;
+}
+
+/// Emits a call or invoke to the given noreturn runtime function.
+void CodeGenFunction::EmitNoreturnRuntimeCallOrInvoke(llvm::Value *callee,
+                                               ArrayRef<llvm::Value*> args) {
+  if (getInvokeDest()) {
+    llvm::InvokeInst *invoke = 
+      Builder.CreateInvoke(callee,
+                           getUnreachableBlock(),
+                           getInvokeDest(),
+                           args);
+    invoke->setDoesNotReturn();
+    invoke->setCallingConv(getRuntimeCC());
+  } else {
+    llvm::CallInst *call = Builder.CreateCall(callee, args);
+    call->setDoesNotReturn();
+    call->setCallingConv(getRuntimeCC());
+    Builder.CreateUnreachable();
+  }
+}
+
+/// Emits a call or invoke instruction to the given nullary runtime
+/// function.
+llvm::CallSite
+CodeGenFunction::EmitRuntimeCallOrInvoke(llvm::Value *callee,
+                                         const Twine &name) {
+  return EmitRuntimeCallOrInvoke(callee, ArrayRef<llvm::Value*>(), name);
+}
+
+/// Emits a call or invoke instruction to the given runtime function.
+llvm::CallSite
+CodeGenFunction::EmitRuntimeCallOrInvoke(llvm::Value *callee,
+                                         ArrayRef<llvm::Value*> args,
+                                         const Twine &name) {
+  llvm::CallSite callSite = EmitCallOrInvoke(callee, args, name);
+  callSite.setCallingConv(getRuntimeCC());
+  return callSite;
+}
+
+llvm::CallSite
+CodeGenFunction::EmitCallOrInvoke(llvm::Value *Callee,
+                                  const Twine &Name) {
+  return EmitCallOrInvoke(Callee, ArrayRef<llvm::Value *>(), Name);
+}
+
 /// Emits a call or invoke instruction to the given function, depending
 /// on the current state of the EH stack.
 llvm::CallSite
@@ -1919,12 +1998,6 @@ CodeGenFunction::EmitCallOrInvoke(llvm::Value *Callee,
   return Inst;
 }
 
-llvm::CallSite
-CodeGenFunction::EmitCallOrInvoke(llvm::Value *Callee,
-                                  const Twine &Name) {
-  return EmitCallOrInvoke(Callee, ArrayRef<llvm::Value *>(), Name);
-}
-
 static void checkArgMatches(llvm::Value *Elt, unsigned &ArgNo,
                             llvm::FunctionType *FTy) {
   if (ArgNo < FTy->getNumParams())