Implement AVX ABI Warning/error

The x86-64 "avx" feature changes how >128 bit vector types are passed,
instead of being passed in separate 128 bit registers, they can be
passed in 256 bit registers.

"avx512f" does the same thing, except it switches from 256 bit registers
to 512 bit registers.

The result of both of these is an ABI incompatibility between functions
compiled with and without these features.

This patch implements a warning/error pair upon an attempt to call a
function that would run afoul of this. First, if a function is called
that would have its ABI changed, we issue a warning.

Second, if said call is made in a situation where the caller and callee
are known to have different calling conventions (such as the case of
'target'), we instead issue an error.

Differential Revision: https://reviews.llvm.org/D82562

1 files changed, 7 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 8724244..7af9869 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -4245,7 +4245,7 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
   llvm::FunctionType *IRFuncTy = getTypes().GetFunctionType(CallInfo);
 
   const Decl *TargetDecl = Callee.getAbstractInfo().getCalleeDecl().getDecl();
-  if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl))
+  if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl)) {
     // We can only guarantee that a function is called from the correct
     // context/function based on the appropriate target attributes,
     // so only check in the case where we have both always_inline and target
@@ -4256,6 +4256,12 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
         TargetDecl->hasAttr<TargetAttr>())
       checkTargetFeatures(Loc, FD);
 
+    // Some architectures (such as x86-64) have the ABI changed based on
+    // attribute-target/features. Give them a chance to diagnose.
+    CGM.getTargetCodeGenInfo().checkFunctionCallABI(
+        CGM, Loc, dyn_cast_or_null<FunctionDecl>(CurCodeDecl), FD, CallArgs);
+  }
+
 #ifndef NDEBUG
   if (!(CallInfo.isVariadic() && CallInfo.getArgStruct())) {
     // For an inalloca varargs function, we don't expect CallInfo to match the