Implement lowering of va_arg in clang directly. (This is 32-bit X86 only for now).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@58681 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index acce366..c4a33245 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -242,3 +242,38 @@
}
}
}
+
+llvm::Value *CodeGenFunction::EmitVAArg(llvm::Value *VAListAddr, QualType Ty)
+{
+ // FIXME: This entire method is hardcoded for 32-bit X86.
+
+ const char *TargetPrefix = getContext().Target.getTargetPrefix();
+
+ if (strcmp(TargetPrefix, "x86") != 0 ||
+ getContext().Target.getPointerWidth(0) != 32)
+ return 0;
+
+ const llvm::Type *BP = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
+ const llvm::Type *BPP = llvm::PointerType::getUnqual(BP);
+
+ llvm::Value *VAListAddrAsBPP = Builder.CreateBitCast(VAListAddr, BPP,
+ "ap");
+ llvm::Value *Addr = Builder.CreateLoad(VAListAddrAsBPP, "ap.cur");
+ llvm::Value *AddrTyped =
+ Builder.CreateBitCast(Addr,
+ llvm::PointerType::getUnqual(ConvertType(Ty)));
+
+ uint64_t SizeInBytes = getContext().getTypeSize(Ty) / 8;
+ const unsigned ArgumentSizeInBytes = 4;
+ if (SizeInBytes < ArgumentSizeInBytes)
+ SizeInBytes = ArgumentSizeInBytes;
+
+ llvm::Value *NextAddr =
+ Builder.CreateGEP(Addr,
+ llvm::ConstantInt::get(llvm::Type::Int32Ty, SizeInBytes),
+ "ap.next");
+ Builder.CreateStore(NextAddr, VAListAddrAsBPP);
+
+ return AddrTyped;
+}
+