add support for linux_riscv64 and freestanding_riscv64

1 files changed, 260 insertions, 9 deletions

diff --git a/src/llvm_abi.cpp b/src/llvm_abi.cpp
index c21cd0a46..0837e40bf 100644
--- a/src/llvm_abi.cpp
+++ b/src/llvm_abi.cpp
@@ -332,7 +332,8 @@ gb_internal 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, bool return_is_tuple, ProcCallingConvention calling_convention, Type *original_type)
+#define LB_ABI_INFO(name) lbFunctionType *name(lbModule *m, LLVMTypeRef *arg_types, unsigned arg_count, LLVMTypeRef return_type, bool return_is_defined, bool return_is_tuple, ProcCallingConvention calling_convention, Type *original_type)
+#define LB_ABI_INFO_CTX(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, Type *original_type)
 typedef LB_ABI_INFO(lbAbiInfoType);
 
 #define LB_ABI_COMPUTE_RETURN_TYPE(name) lbArgType name(lbFunctionType *ft, LLVMContextRef c, LLVMTypeRef return_type, bool return_is_defined, bool return_is_tuple)
@@ -379,7 +380,7 @@ namespace lbAbi386 {
 	gb_internal Array<lbArgType> compute_arg_types(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count);
 	gb_internal LB_ABI_COMPUTE_RETURN_TYPE(compute_return_type);
 
-	gb_internal LB_ABI_INFO(abi_info) {
+	gb_internal LB_ABI_INFO_CTX(abi_info) {
 		lbFunctionType *ft = gb_alloc_item(permanent_allocator(), lbFunctionType);
 		ft->ctx = c;
 		ft->args = compute_arg_types(c, arg_types, arg_count);
@@ -460,7 +461,7 @@ namespace lbAbiAmd64Win64 {
 	gb_internal Array<lbArgType> compute_arg_types(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count);
 	gb_internal LB_ABI_COMPUTE_RETURN_TYPE(compute_return_type);
 
-	gb_internal LB_ABI_INFO(abi_info) {
+	gb_internal LB_ABI_INFO_CTX(abi_info) {
 		lbFunctionType *ft = gb_alloc_item(permanent_allocator(), lbFunctionType);
 		ft->ctx = c;
 		ft->args = compute_arg_types(c, arg_types, arg_count);
@@ -570,7 +571,7 @@ namespace lbAbiAmd64SysV {
 	gb_internal Array<RegClass> classify(LLVMTypeRef t);
 	gb_internal LLVMTypeRef llreg(LLVMContextRef c, Array<RegClass> const &reg_classes, LLVMTypeRef type);
 
-	gb_internal LB_ABI_INFO(abi_info) {
+	gb_internal LB_ABI_INFO_CTX(abi_info) {
 		lbFunctionType *ft = gb_alloc_item(permanent_allocator(), lbFunctionType);
 		ft->ctx = c;
 		ft->calling_convention = calling_convention;
@@ -1008,7 +1009,7 @@ namespace lbAbiArm64 {
 	gb_internal LB_ABI_COMPUTE_RETURN_TYPE(compute_return_type);
 	gb_internal bool is_homogenous_aggregate(LLVMContextRef c, LLVMTypeRef type, LLVMTypeRef *base_type_, unsigned *member_count_);
 
-	gb_internal LB_ABI_INFO(abi_info) {
+	gb_internal LB_ABI_INFO_CTX(abi_info) {
 		lbFunctionType *ft = gb_alloc_item(permanent_allocator(), lbFunctionType);
 		ft->ctx = c;
 		ft->args = compute_arg_types(c, arg_types, arg_count);
@@ -1242,7 +1243,7 @@ namespace lbAbiWasm {
 
 	enum {MAX_DIRECT_STRUCT_SIZE = 32};
 
-	gb_internal LB_ABI_INFO(abi_info) {
+	gb_internal LB_ABI_INFO_CTX(abi_info) {
 		lbFunctionType *ft = gb_alloc_item(permanent_allocator(), lbFunctionType);
 		ft->ctx = c;
 		ft->calling_convention = calling_convention;
@@ -1407,7 +1408,7 @@ namespace lbAbiArm32 {
 	gb_internal Array<lbArgType> compute_arg_types(LLVMContextRef c, LLVMTypeRef *arg_types, unsigned arg_count, ProcCallingConvention calling_convention);
 	gb_internal lbArgType compute_return_type(LLVMContextRef c, LLVMTypeRef return_type, bool return_is_defined);
 
-	gb_internal LB_ABI_INFO(abi_info) {
+	gb_internal LB_ABI_INFO_CTX(abi_info) {
 		lbFunctionType *ft = gb_alloc_item(permanent_allocator(), lbFunctionType);
 		ft->ctx = c;
 		ft->args = compute_arg_types(c, arg_types, arg_count, calling_convention);
@@ -1485,8 +1486,256 @@ namespace lbAbiArm32 {
 	}
 };
 
+namespace lbAbiRiscv64 {
+
+	gb_internal bool is_register(LLVMTypeRef type) {
+		LLVMTypeKind kind = LLVMGetTypeKind(type);
+		switch (kind) {
+		case LLVMIntegerTypeKind:
+		case LLVMHalfTypeKind:
+		case LLVMFloatTypeKind:
+		case LLVMDoubleTypeKind:
+		case LLVMPointerTypeKind:
+			return true;
+		}
+		return false;
+	}
+
+	gb_internal bool is_float(LLVMTypeRef type) {
+		LLVMTypeKind kind = LLVMGetTypeKind(type);
+		switch (kind) {
+		case LLVMHalfTypeKind:
+		case LLVMFloatTypeKind:
+		case LLVMDoubleTypeKind:
+			return true;
+		default:
+			return false;
+		}
+	}
+
+	gb_internal lbArgType non_struct(LLVMContextRef c, LLVMTypeRef type) {
+		LLVMAttributeRef attr = nullptr;
+		LLVMTypeRef i1 = LLVMInt1TypeInContext(c);
+		if (type == i1) {
+			attr = lb_create_enum_attribute(c, "zeroext");
+		}
+		return lb_arg_type_direct(type, nullptr, nullptr, attr);
+	}
+
+	gb_internal void flatten(lbModule *m, Array<LLVMTypeRef> *fields, LLVMTypeRef type, bool with_padding) {
+		LLVMTypeKind kind = LLVMGetTypeKind(type);
+		switch (kind) {
+		case LLVMStructTypeKind: {
+			if (LLVMIsPackedStruct(type)) {
+				array_add(fields, type);
+				break;
+			}
+
+			if (!with_padding) {
+				auto field_remapping = map_get(&m->struct_field_remapping, cast(void *)type);
+				if (field_remapping) {
+					auto remap = *field_remapping;
+					for_array(i, remap) {
+						flatten(m, fields, LLVMStructGetTypeAtIndex(type, remap[i]), with_padding);
+					}
+					break;
+				} else {
+					debugf("no field mapping for type: %s\n", LLVMPrintTypeToString(type));
+				}
+			}
+
+			unsigned elem_count = LLVMCountStructElementTypes(type);
+			for (unsigned i = 0; i < elem_count; i += 1) {
+				flatten(m, fields, LLVMStructGetTypeAtIndex(type, i), with_padding);
+			}
+			break;
+		}
+		case LLVMArrayTypeKind: {
+			unsigned len     = LLVMGetArrayLength(type);
+			LLVMTypeRef elem = OdinLLVMGetArrayElementType(type);
+			for (unsigned i = 0; i < len; i += 1) {
+				flatten(m, fields, elem, with_padding);
+			}
+			break;
+		}
+		default:
+			array_add(fields, type);
+		}
+	}
+
+	gb_internal lbArgType compute_arg_type(lbModule *m, LLVMTypeRef type, int *gprs_left, int *fprs_left, Type *odin_type) {
+		LLVMContextRef c = m->ctx;
+
+		int xlen = 8; // 8 byte int register size for riscv64.
+
+		// NOTE: we are requiring both of these to be enabled so we can just hard-code 8.
+		// int flen = 0;
+		// if (check_target_feature_is_enabled(str_lit("d"), nullptr)) {
+		// 	flen = 8; // Double precision floats are enabled.
+		// } else if (check_target_feature_is_enabled(str_lit("f"), nullptr)) {
+		// 	flen = 4; // Single precision floats are enabled.
+		// }
+		int flen = 8;
+
+		LLVMTypeKind kind = LLVMGetTypeKind(type);
+		i64 size = lb_sizeof(type);
+
+		if (size == 0) {
+			return lb_arg_type_direct(type, LLVMStructTypeInContext(c, nullptr, 0, false), nullptr, nullptr);
+		}
+
+		LLVMTypeRef orig_type = type;
+
+		// Flatten down the type so it is easier to check all the ABI conditions.
+		// Note that we also need to remove all implicit padding fields Odin adds so we keep ABI
+		// compatibility for struct declarations.
+		if (kind == LLVMStructTypeKind && size <= gb_max(2*xlen, 2*flen)) {
+			Array<LLVMTypeRef> fields = array_make<LLVMTypeRef>(temporary_allocator(), 0, LLVMCountStructElementTypes(type));
+			flatten(m, &fields, type, false);
+
+			if (fields.count == 1) {
+				type = fields[0];
+			} else {
+				type = LLVMStructTypeInContext(c, fields.data, cast(unsigned)fields.count, false);
+			}
+
+			kind = LLVMGetTypeKind(type);
+			size = lb_sizeof(type);
+			GB_ASSERT_MSG(size == lb_sizeof(orig_type), "flattened: %s of size %d, original: %s of size %d", LLVMPrintTypeToString(type), size, LLVMPrintTypeToString(orig_type), lb_sizeof(orig_type));
+		}
+
+		if (is_float(type) && size <= flen && *fprs_left >= 1) {
+			*fprs_left -= 1;
+			return non_struct(c, orig_type);
+		}
+
+		if (kind == LLVMStructTypeKind && size <= 2*flen) {
+			unsigned elem_count = LLVMCountStructElementTypes(type);
+			if (elem_count == 2) {
+				LLVMTypeRef ty1 = LLVMStructGetTypeAtIndex(type, 0);
+				i64 ty1s = lb_sizeof(ty1);
+				LLVMTypeRef ty2 = LLVMStructGetTypeAtIndex(type, 1);
+				i64 ty2s = lb_sizeof(ty2);
+
+				if (is_float(ty1) && is_float(ty2) && ty1s <= flen && ty2s <= flen && *fprs_left >= 2) {
+					*fprs_left -= 2;
+					return lb_arg_type_direct(orig_type, type, nullptr, nullptr);
+				}
+
+				if (is_float(ty1) && is_register(ty2) && ty1s <= flen && ty2s <= xlen && *fprs_left >= 1 && *gprs_left >= 1) {
+					*fprs_left -= 1;
+					*gprs_left -= 1;
+					return lb_arg_type_direct(orig_type, type, nullptr, nullptr);
+				}
+
+				if (is_register(ty1) && is_float(ty2) && ty1s <= xlen && ty2s <= flen && *gprs_left >= 1 && *fprs_left >= 1) {
+					*fprs_left -= 1;
+					*gprs_left -= 1;
+					return lb_arg_type_direct(orig_type, type, nullptr, nullptr);
+				}
+			}
+		}
+
+		// At this point all the cases for floating point registers are exhausted, fit it into
+		// integer registers or the stack.
+		// LLVM automatically handles putting args on the stack so we don't check the amount of registers that are left here.
+
+		if (size <= xlen) {
+			*gprs_left -= 1;
+			if (is_register(type)) {
+				return non_struct(c, orig_type);
+			} else {
+				return lb_arg_type_direct(orig_type, LLVMIntTypeInContext(c, cast(unsigned)(size*8)), nullptr, nullptr);
+			}
+		} else if (size <= 2*xlen) {
+			LLVMTypeRef *fields = gb_alloc_array(temporary_allocator(), LLVMTypeRef, 2);
+			fields[0] = LLVMIntTypeInContext(c, cast(unsigned)(xlen*8));
+			fields[1] = LLVMIntTypeInContext(c, cast(unsigned)((size-xlen)*8));
+
+			*gprs_left -= 2;
+			return lb_arg_type_direct(orig_type, LLVMStructTypeInContext(c, fields, 2, false), nullptr, nullptr);
+		} else {
+			return lb_arg_type_indirect(orig_type, nullptr);
+		}
+	}
+
+	gb_internal Array<lbArgType> compute_arg_types(lbModule *m, LLVMTypeRef *arg_types, unsigned arg_count, ProcCallingConvention calling_convention, Type *odin_type, int *gprs, int *fprs) {
+		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];
+			args[i] = compute_arg_type(m, type, gprs, fprs, odin_type);
+		}
+
+		return args;
+	}
+
+	gb_internal lbArgType compute_return_type(lbFunctionType *ft, lbModule *m, LLVMTypeRef return_type, bool return_is_defined, bool return_is_tuple, Type *odin_type, int *agprs) {
+		LLVMContextRef c = m->ctx;
+
+		if (!return_is_defined) {
+			return lb_arg_type_direct(LLVMVoidTypeInContext(c));
+		}
+
+		// There are two registers for return types.
+		int gprs = 2;
+		int fprs = 2;
+		lbArgType ret = compute_arg_type(m, return_type, &gprs, &fprs, odin_type);
+
+		// Return didn't fit into the return registers, so caller allocates and it is returned via
+		// an out-pointer.
+		if (ret.kind == lbArg_Indirect) {
+
+			// Transform multiple return into out pointers if possible.
+			if (return_is_tuple) {
+				if (lb_is_type_kind(return_type, LLVMStructTypeKind)) {
+					int field_count = cast(int)LLVMCountStructElementTypes(return_type);
+					if (field_count > 1 && field_count <= *agprs) {
+						ft->original_arg_count = ft->args.count;
+						ft->multiple_return_original_type = return_type;
+
+						for (int 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);
+							*agprs -= 1;
+						}
+						GB_ASSERT(*agprs >= 0);
+
+						// override the return type for the last field
+						LLVMTypeRef new_return_type = LLVMStructGetTypeAtIndex(return_type, field_count-1);
+						return compute_return_type(ft, m, new_return_type, true, false, odin_type, agprs);
+					}
+				}
+			}
+
+			LLVMAttributeRef attr = lb_create_enum_attribute_with_type(c, "sret", ret.type);
+			return lb_arg_type_indirect(ret.type, attr);
+		}
+
+		return ret;
+	}
+
+	gb_internal LB_ABI_INFO(abi_info) {
+		lbFunctionType *ft = gb_alloc_item(permanent_allocator(), lbFunctionType);
+		ft->ctx = m->ctx;
+		ft->calling_convention = calling_convention;
+
+		int gprs = 8;
+		int fprs = 8;
+
+		ft->args = compute_arg_types(m, arg_types, arg_count, calling_convention, original_type, &gprs, &fprs);
+		ft->ret = compute_return_type(ft, m, return_type, return_is_defined, return_is_tuple, original_type, &gprs);
+
+		return ft;
+	}
+}
+
 
 gb_internal LB_ABI_INFO(lb_get_abi_info_internal) {
+	LLVMContextRef c = m->ctx;
+
 	switch (calling_convention) {
 	case ProcCC_None:
 	case ProcCC_InlineAsm:
@@ -1534,6 +1783,8 @@ gb_internal LB_ABI_INFO(lb_get_abi_info_internal) {
 		return lbAbiWasm::abi_info(c, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention, original_type);
 	case TargetArch_wasm64p32:
 		return lbAbiWasm::abi_info(c, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention, original_type);
+	case TargetArch_riscv64:
+		return lbAbiRiscv64::abi_info(m, arg_types, arg_count, return_type, return_is_defined, return_is_tuple, calling_convention, original_type);
 	}
 
 	GB_PANIC("Unsupported ABI");
@@ -1543,7 +1794,7 @@ gb_internal LB_ABI_INFO(lb_get_abi_info_internal) {
 
 gb_internal LB_ABI_INFO(lb_get_abi_info) {
 	lbFunctionType *ft = lb_get_abi_info_internal(
-		c,
+		m,
 		arg_types, arg_count,
 		return_type, return_is_defined,
 		ALLOW_SPLIT_MULTI_RETURNS && return_is_tuple && is_calling_convention_odin(calling_convention),
@@ -1555,7 +1806,7 @@ gb_internal LB_ABI_INFO(lb_get_abi_info) {
 	// This is to make it consistent when and how it is handled
 	if (calling_convention == ProcCC_Odin) {
 		// append the `context` pointer
-		lbArgType context_param = lb_arg_type_direct(LLVMPointerType(LLVMInt8TypeInContext(c), 0));
+		lbArgType context_param = lb_arg_type_direct(LLVMPointerType(LLVMInt8TypeInContext(m->ctx), 0));
 		array_add(&ft->args, context_param);
 	}