Commit d24345386274e3abcbcc676fe65bda127c06ce8e | zig

author	Andrew Kelley <andrew@ziglang.org> 2018-02-27 17:47:18-05:00
committer	Andrew Kelley <andrew@ziglang.org> 2018-02-27 17:47:18-05:00
log	d24345386274e3abcbcc676fe65bda127c06ce8e
tree	b5945c207d3ce6dff2631af9c30f35d2e72c6c55
parent	138d6f909321fb4fddeaa172357336c384c64eda

Revert "llvm coroutine workaround: sret functions return sret pointer"

This reverts commit 132e604aa399a3bcb91996e550cf8972bd88422c.

this workaround didn't work either

2 files changed, 4 insertions(+), 14 deletions(-)

src
- analyze.cpp
- codegen.cpp

src/analyze.cpp+1-4

...	@@ -1026,10 +1026,7 @@ TypeTableEntry get_fn_type(CodeGen g, FnTypeId *fn_type_id) {	...	@@ -1026,10 +1026,7 @@ TypeTableEntry get_fn_type(CodeGen g, FnTypeId *fn_type_id) {
1026	gen_param_index += 1;	1026	gen_param_index += 1;
1027	// after the gen_param_index += 1 because 0 is the return type	1027	// after the gen_param_index += 1 because 0 is the return type
1028	param_di_types[gen_param_index] = gen_type->di_type;	1028	param_di_types[gen_param_index] = gen_type->di_type;
1029		1029	gen_return_type = g->builtin_types.entry_void;
1030	// as a workaround for LLVM coroutines not understanding instruction dependencies,
1031	// we return the sret pointer argument instead of returning void
1032	gen_return_type = gen_type;
1033	} else {	1030	} else {
1034	gen_return_type = fn_type_id->return_type;	1031	gen_return_type = fn_type_id->return_type;
1035	}	1032	}

src/codegen.cpp+3-10

 @@ -547,10 +547,7 @@ static LLVMValueRef fn_llvm_value(CodeGen *g, FnTableEntry *fn_table_entry) {
     } else if (handle_is_ptr(return_type) &&
             calling_convention_does_first_arg_return(fn_type->data.fn.fn_type_id.cc))
     {
-        // We do not add the sret attribute, because it would require the return type to be void,
+        addLLVMArgAttr(fn_table_entry->llvm_value, 0, "sret");
-        // and we want the return value to return the sret pointer, to work around LLVM Coroutine
-        // transformation passes not understanding the data dependency.
-        //addLLVMArgAttr(fn_table_entry->llvm_value, 0, "sret");
         addLLVMArgAttr(fn_table_entry->llvm_value, 0, "nonnull");
     }
 @@ -1619,9 +1616,7 @@ static LLVMValueRef ir_render_return(CodeGen *g, IrExecutable *executable, IrIns
         if (calling_convention_does_first_arg_return(g->cur_fn->type_entry->data.fn.fn_type_id.cc)) {
             assert(g->cur_ret_ptr);
             gen_assign_raw(g, g->cur_ret_ptr, get_pointer_to_type(g, return_type, false), value);
-            // as a workaround for LLVM coroutines not understanding instruction dependencies,
+            LLVMBuildRetVoid(g->builder);
-            // we return the sret pointer argument instead of returning void
-            LLVMBuildRet(g->builder, g->cur_ret_ptr);
         } else {
             LLVMValueRef by_val_value = gen_load_untyped(g, value, 0, false, "");
             LLVMBuildRet(g->builder, by_val_value);
 @@ -2774,9 +2769,7 @@ static LLVMValueRef ir_render_call(CodeGen *g, IrExecutable *executable, IrInstr
     } else if (!ret_has_bits) {
         return nullptr;
     } else if (first_arg_ret) {
-        // instead of returning instruction->tmp_ptr here, we trust that the function returned the first arg.
+        return instruction->tmp_ptr;
-        // this is a workaround for llvm coroutines not understanding the data dependency
-        return result;
     } else {
         return result;
     }