Basic support for new ABI experiment on Win64

1 files changed, 90 insertions, 21 deletions

diff --git a/src/llvm_abi.cpp b/src/llvm_abi.cpp
index 298041aa6..31773e1a2 100644
--- a/src/llvm_abi.cpp
+++ b/src/llvm_abi.cpp
@@ -1,3 +1,5 @@
+#define ALLOW_SPLIT_MULTI_RETURNS true
+
 enum lbArgKind {
 	lbArg_Direct,
 	lbArg_Indirect,
@@ -48,8 +50,16 @@ struct lbFunctionType {
 	ProcCallingConvention calling_convention;
 	Array<lbArgType> args;
 	lbArgType        ret;
+
+	LLVMTypeRef      multiple_return_original_type; // nullptr if not used
+	isize            original_arg_count;
 };
 
+gbAllocator lb_function_type_args_allocator(void) {
+	return heap_allocator();
+}
+
+
 i64 llvm_align_formula(i64 off, i64 a) {
 	return (off + a - 1) / a * a;
 }
@@ -100,7 +110,9 @@ LLVMTypeRef lb_function_type_to_llvm_raw(lbFunctionType *ft, bool is_var_arg) {
 			}
 			args[arg_index++] = arg_type;
 		} else if (arg->kind == lbArg_Indirect) {
-			GB_ASSERT(!lb_is_type_kind(arg->type, LLVMPointerTypeKind));
+			if (ft->multiple_return_original_type == nullptr || i < ft->original_arg_count) {
+				GB_ASSERT(!lb_is_type_kind(arg->type, LLVMPointerTypeKind));
+			}
 			args[arg_index++] = LLVMPointerType(arg->type, 0);
 		} else if (arg->kind == lbArg_Ignore) {
 			// ignore
@@ -147,6 +159,13 @@ void lb_add_function_type_attributes(LLVMValueRef fn, lbFunctionType *ft, ProcCa
 			LLVMAddAttributeAtIndex(fn, arg_index+1, arg->align_attribute);
 		}
 
+		if (ft->multiple_return_original_type) {
+			if (ft->original_arg_count <= i) {
+				LLVMAddAttributeAtIndex(fn, arg_index+1, noalias_attr);
+				LLVMAddAttributeAtIndex(fn, arg_index+1, nonnull_attr);
+			}
+		}
+
 		arg_index++;
 	}
 
@@ -307,7 +326,7 @@ i64 lb_alignof(LLVMTypeRef type) {
 }
 
 
-#define LB_ABI_INFO(name) lbFunctionType *name(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count, LLVMTypeRef return_type, bool return_is_defined, ProcCallingConvention calling_convention)
+#define LB_ABI_INFO(name) lbFunctionType *name(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count, LLVMTypeRef return_type, bool return_is_defined, bool return_is_tuple, ProcCallingConvention calling_convention)
 typedef LB_ABI_INFO(lbAbiInfoType);
 
 
@@ -353,7 +372,7 @@ namespace lbAbi386 {
 	}
 
 	Array<lbArgType> compute_arg_types(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count) {
-		auto args = array_make<lbArgType>(heap_allocator(), arg_count);
+		auto args = array_make<lbArgType>(lb_function_type_args_allocator(), arg_count);
 
 		for (unsigned i = 0; i < arg_count; i++) {
 			LLVMTypeRef t = arg_types[i];
@@ -392,19 +411,19 @@ namespace lbAbi386 {
 
 namespace lbAbiAmd64Win64 {
 	Array<lbArgType> compute_arg_types(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count);
-
+	lbArgType compute_return_type(lbFunctionType *ft, LLVMContextRef c, LLVMTypeRef return_type, bool return_is_defined, bool return_is_tuple);
 
 	LB_ABI_INFO(abi_info) {
 		lbFunctionType *ft = gb_alloc_item(permanent_allocator(), lbFunctionType);
 		ft->ctx = c;
 		ft->args = compute_arg_types(c, arg_types, arg_count);
-		ft->ret = lbAbi386::compute_return_type(c, return_type, return_is_defined);
+		ft->ret = compute_return_type(ft, c, return_type, return_is_defined, return_is_tuple);
 		ft->calling_convention = calling_convention;
 		return ft;
 	}
 
 	Array<lbArgType> compute_arg_types(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count) {
-		auto args = array_make<lbArgType>(heap_allocator(), arg_count);
+		auto args = array_make<lbArgType>(lb_function_type_args_allocator(), arg_count);
 
 		for (unsigned i = 0; i < arg_count; i++) {
 			LLVMTypeRef t = arg_types[i];
@@ -428,6 +447,45 @@ namespace lbAbiAmd64Win64 {
 		}
 		return args;
 	}
+
+	lbArgType compute_return_type(lbFunctionType *ft, LLVMContextRef c, LLVMTypeRef return_type, bool return_is_defined, bool return_is_tuple) {
+		if (!return_is_defined) {
+			return lb_arg_type_direct(LLVMVoidTypeInContext(c));
+		} else if (lb_is_type_kind(return_type, LLVMStructTypeKind) || lb_is_type_kind(return_type, LLVMArrayTypeKind)) {
+			i64 sz = lb_sizeof(return_type);
+			switch (sz) {
+			case 1: return lb_arg_type_direct(return_type, LLVMIntTypeInContext(c,  8), nullptr, nullptr);
+			case 2: return lb_arg_type_direct(return_type, LLVMIntTypeInContext(c, 16), nullptr, nullptr);
+			case 4: return lb_arg_type_direct(return_type, LLVMIntTypeInContext(c, 32), nullptr, nullptr);
+			case 8: return lb_arg_type_direct(return_type, LLVMIntTypeInContext(c, 64), nullptr, nullptr);
+			}
+
+			if (return_is_tuple) {
+				GB_ASSERT(lb_is_type_kind(return_type, LLVMStructTypeKind));
+				unsigned field_count = LLVMCountStructElementTypes(return_type);
+
+				if (field_count > 1) {
+					ft->original_arg_count = ft->args.count;
+					ft->multiple_return_original_type = return_type;
+
+					for (unsigned i = 0; i < field_count-1; i++) {
+						LLVMTypeRef field_type = LLVMStructGetTypeAtIndex(return_type, i);
+						LLVMTypeRef field_pointer_type = LLVMPointerType(field_type, 0);
+						lbArgType ret_partial = lb_arg_type_direct(field_pointer_type);
+						array_add(&ft->args, ret_partial);
+					}
+
+					// override the return type for the last field
+					LLVMTypeRef new_return_type = LLVMStructGetTypeAtIndex(return_type, field_count-1);
+					return compute_return_type(ft, c, new_return_type, true, false);
+				}
+			}
+
+			LLVMAttributeRef attr = lb_create_enum_attribute_with_type(c, "sret", return_type);
+			return lb_arg_type_indirect(return_type, attr);
+		}
+		return lbAbi386::non_struct(c, return_type, true);
+	}
 };
 
 // NOTE(bill): I hate `namespace` in C++ but this is just because I don't want to prefix everything
@@ -490,7 +548,7 @@ namespace lbAbiAmd64SysV {
 		ft->ctx = c;
 		ft->calling_convention = calling_convention;
 
-		ft->args = array_make<lbArgType>(heap_allocator(), arg_count);
+		ft->args = array_make<lbArgType>(lb_function_type_args_allocator(), arg_count);
 		for (unsigned i = 0; i < arg_count; i++) {
 			ft->args[i] = amd64_type(c, arg_types[i], Amd64TypeAttribute_ByVal, calling_convention);
 		}
@@ -1056,7 +1114,7 @@ namespace lbAbiArm64 {
 	}
     
 	Array<lbArgType> compute_arg_types(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count) {
-		auto args = array_make<lbArgType>(heap_allocator(), arg_count);
+		auto args = array_make<lbArgType>(lb_function_type_args_allocator(), arg_count);
 
 		for (unsigned i = 0; i < arg_count; i++) {
 			LLVMTypeRef type = arg_types[i];
@@ -1188,7 +1246,7 @@ namespace lbAbiWasm {
 	
 
 	Array<lbArgType> compute_arg_types(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count) {
-		auto args = array_make<lbArgType>(heap_allocator(), arg_count);
+		auto args = array_make<lbArgType>(lb_function_type_args_allocator(), arg_count);
 
 		for (unsigned i = 0; i < arg_count; i++) {
 			LLVMTypeRef t = arg_types[i];
@@ -1266,7 +1324,7 @@ namespace lbAbiArm32 {
 	}
 
 	Array<lbArgType> compute_arg_types(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count, ProcCallingConvention calling_convention) {
-		auto args = array_make<lbArgType>(heap_allocator(), arg_count);
+		auto args = array_make<lbArgType>(lb_function_type_args_allocator(), arg_count);
 
 		for (unsigned i = 0; i < arg_count; i++) {
 			LLVMTypeRef t = arg_types[i];
@@ -1307,14 +1365,14 @@ namespace lbAbiArm32 {
 };
 
 
-LB_ABI_INFO(lb_get_abi_info) {
+LB_ABI_INFO(lb_get_abi_info_internal) {
 	switch (calling_convention) {
 	case ProcCC_None:
 	case ProcCC_InlineAsm:
 		{
 			lbFunctionType *ft = gb_alloc_item(permanent_allocator(), lbFunctionType);
 			ft->ctx = c;
-			ft->args = array_make<lbArgType>(heap_allocator(), arg_count);
+			ft->args = array_make<lbArgType>(lb_function_type_args_allocator(), arg_count);
 			for (unsigned i = 0; i < arg_count; i++) {
 				ft->args[i] = lb_arg_type_direct(arg_types[i]);
 			}
@@ -1328,32 +1386,43 @@ LB_ABI_INFO(lb_get_abi_info) {
 		}
 	case ProcCC_Win64:
 		GB_ASSERT(build_context.metrics.arch == TargetArch_amd64);
-		return lbAbiAmd64Win64::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
+		return lbAbiAmd64Win64::abi_info(c, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention);
 	case ProcCC_SysV:
 		GB_ASSERT(build_context.metrics.arch == TargetArch_amd64);
-		return lbAbiAmd64SysV::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
+		return lbAbiAmd64SysV::abi_info(c, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention);
 	}
 
 	switch (build_context.metrics.arch) {
 	case TargetArch_amd64:
 		if (build_context.metrics.os == TargetOs_windows || build_context.metrics.abi == TargetABI_Win64) {
-			return lbAbiAmd64Win64::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
+			return lbAbiAmd64Win64::abi_info(c, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention);
 		} else if (build_context.metrics.abi == TargetABI_SysV) {
-			return lbAbiAmd64SysV::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
+			return lbAbiAmd64SysV::abi_info(c, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention);
 		} else {
-			return lbAbiAmd64SysV::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
+			return lbAbiAmd64SysV::abi_info(c, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention);
 		}
 	case TargetArch_i386:
-		return lbAbi386::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
+		return lbAbi386::abi_info(c, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention);
 	case TargetArch_arm32:
-		return lbAbiArm32::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
+		return lbAbiArm32::abi_info(c, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention);
 	case TargetArch_arm64:
-		return lbAbiArm64::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
+		return lbAbiArm64::abi_info(c, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention);
 	case TargetArch_wasm32:
 	case TargetArch_wasm64:
-		return lbAbiWasm::abi_info(c, arg_types, arg_count, return_type, return_is_defined, calling_convention);
+		return lbAbiWasm::abi_info(c, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention);
 	}
 
 	GB_PANIC("Unsupported ABI");
 	return {};
 }
+
+
+LB_ABI_INFO(lb_get_abi_info) {
+	lbFunctionType *ft = lb_get_abi_info_internal(c, arg_types, arg_count, return_type, return_is_defined, ALLOW_SPLIT_MULTI_RETURNS && return_is_tuple, calling_convention);
+	if (calling_convention == ProcCC_Odin) {
+		// append the `context` pointer
+		lbArgType context_param = lb_arg_type_direct(LLVMPointerType(LLVMInt8TypeInContext(c), 0));
+		array_add(&ft->args, context_param);
+	}
+	return ft;
+}