From 72404db31f76635f11d0aa4dcc02c149ef885b3d Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Sun, 28 Feb 2021 22:01:13 -0700
Subject: [PATCH] stage1: update to LLVM 12 sret callsite requirements

Without this, the LLVM IR that zig generates cannot be compiled by LLVM.
---
 src/stage1/codegen.cpp | 8 +-------
 src/zig_llvm.cpp       | 9 +++++++++
 src/zig_llvm.h         | 1 +
 3 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/stage1/codegen.cpp b/src/stage1/codegen.cpp
index 389ede91b7..1338f58e30 100644
--- a/src/stage1/codegen.cpp
+++ b/src/stage1/codegen.cpp
@@ -4037,12 +4037,6 @@ static void gen_set_stack_pointer(CodeGen *g, LLVMValueRef aligned_end_addr) {
     LLVMBuildCall(g->builder, write_register_fn_val, params, 2, "");
 }
 
-static void set_call_instr_sret(CodeGen *g, LLVMValueRef call_instr) {
-    unsigned attr_kind_id = LLVMGetEnumAttributeKindForName("sret", 4);
-    LLVMAttributeRef sret_attr = LLVMCreateEnumAttribute(LLVMGetGlobalContext(), attr_kind_id, 0);
-    LLVMAddCallSiteAttribute(call_instr, 1, sret_attr);
-}
-
 static void render_async_spills(CodeGen *g) {
     ZigType *fn_type = g->cur_fn->type_entry;
     ZigType *import = get_scope_import(&g->cur_fn->fndef_scope->base);
@@ -4558,7 +4552,7 @@ static LLVMValueRef ir_render_call(CodeGen *g, IrExecutableGen *executable, IrIn
     } else if (!ret_has_bits) {
         return nullptr;
     } else if (first_arg_ret) {
-        set_call_instr_sret(g, result);
+        ZigLLVMSetCallSret(result, get_llvm_type(g, src_return_type));
         return result_loc;
     } else if (handle_is_ptr(g, src_return_type)) {
         LLVMValueRef store_instr = LLVMBuildStore(g->builder, result, result_loc);
diff --git a/src/zig_llvm.cpp b/src/zig_llvm.cpp
index 55e507c6d0..5a7d60f83b 100644
--- a/src/zig_llvm.cpp
+++ b/src/zig_llvm.cpp
@@ -940,6 +940,15 @@ void ZigLLVMSetTailCall(LLVMValueRef Call) {
     unwrap<CallInst>(Call)->setTailCallKind(CallInst::TCK_MustTail);
 } 
 
+void ZigLLVMSetCallSret(LLVMValueRef Call, LLVMTypeRef return_type) {
+    const AttributeList attr_set = unwrap<CallInst>(Call)->getAttributes();
+    AttrBuilder attr_builder;
+    Type *llvm_type = unwrap<Type>(return_type);
+    attr_builder.addStructRetAttr(llvm_type);
+    const AttributeList new_attr_set = attr_set.addAttributes(unwrap<CallInst>(Call)->getContext(), 1, attr_builder);
+    unwrap<CallInst>(Call)->setAttributes(new_attr_set);
+}
+
 void ZigLLVMFunctionSetPrefixData(LLVMValueRef function, LLVMValueRef data) {
     unwrap<Function>(function)->setPrefixData(unwrap<Constant>(data));
 }
diff --git a/src/zig_llvm.h b/src/zig_llvm.h
index c8ffa32e81..0d08980835 100644
--- a/src/zig_llvm.h
+++ b/src/zig_llvm.h
@@ -264,6 +264,7 @@ ZIG_EXTERN_C struct ZigLLVMDILocation *ZigLLVMGetDebugLoc(unsigned line, unsigne
 
 ZIG_EXTERN_C void ZigLLVMSetFastMath(LLVMBuilderRef builder_wrapped, bool on_state);
 ZIG_EXTERN_C void ZigLLVMSetTailCall(LLVMValueRef Call);
+ZIG_EXTERN_C void ZigLLVMSetCallSret(LLVMValueRef Call, LLVMTypeRef return_type);
 ZIG_EXTERN_C void ZigLLVMFunctionSetPrefixData(LLVMValueRef fn, LLVMValueRef data);
 ZIG_EXTERN_C void ZigLLVMFunctionSetCallingConv(LLVMValueRef function, enum ZigLLVM_CallingConv cc);