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error return traces use a zig-provided function to save binary size

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This commit is contained in:
Andrew Kelley 2018-01-14 16:26:06 -05:00
parent fa024f8092
commit f0df2cdde9
2 changed files with 86 additions and 26 deletions
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2
src/all_types.hpp
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@ -1574,6 +1574,8 @@ struct CodeGen {
size_t largest_err_name_len;
LLVMValueRef safety_crash_err_fn;
LLVMValueRef return_err_fn;
IrInstruction *invalid_instruction;
ConstExprValue const_void_val;

110
src/codegen.cpp
View File

@ -892,7 +892,8 @@ static void gen_panic(CodeGen *g, LLVMValueRef msg_arg, LLVMValueRef stack_trace
msg_arg,
stack_trace_arg,
};
ZigLLVMBuildCall(g->builder, fn_val, args, 2, llvm_cc, ZigLLVM_FnInlineAuto, "");
LLVMValueRef call_instruction = ZigLLVMBuildCall(g->builder, fn_val, args, 2, llvm_cc, ZigLLVM_FnInlineAuto, "");
LLVMSetTailCall(call_instruction, true);
LLVMBuildUnreachable(g->builder);
}
@ -919,6 +920,79 @@ static LLVMValueRef get_memcpy_fn_val(CodeGen *g) {
return g->memcpy_fn_val;
}
static LLVMValueRef get_return_err_fn(CodeGen *g) {
if (g->return_err_fn != nullptr)
return g->return_err_fn;
assert(g->err_tag_type != nullptr);
LLVMTypeRef ptr_u8 = LLVMPointerType(LLVMInt8Type(), 0);
LLVMTypeRef arg_types[] = {
// error return trace pointer
get_ptr_to_stack_trace_type(g)->type_ref,
// return address
ptr_u8,
};
LLVMTypeRef fn_type_ref = LLVMFunctionType(LLVMVoidType(), arg_types, 2, false);
Buf *fn_name = get_mangled_name(g, buf_create_from_str("__zig_return_error"), false);
LLVMValueRef fn_val = LLVMAddFunction(g->module, buf_ptr(fn_name), fn_type_ref);
addLLVMFnAttr(fn_val, "cold");
LLVMSetLinkage(fn_val, LLVMInternalLinkage);
LLVMSetFunctionCallConv(fn_val, get_llvm_cc(g, CallingConventionUnspecified));
addLLVMFnAttr(fn_val, "nounwind");
add_uwtable_attr(g, fn_val);
addLLVMArgAttr(fn_val, (unsigned)0, "nonnull");
addLLVMArgAttr(fn_val, (unsigned)1, "nonnull");
if (g->build_mode == BuildModeDebug) {
ZigLLVMAddFunctionAttr(fn_val, "no-frame-pointer-elim", "true");
ZigLLVMAddFunctionAttr(fn_val, "no-frame-pointer-elim-non-leaf", nullptr);
}
LLVMBasicBlockRef entry_block = LLVMAppendBasicBlock(fn_val, "Entry");
LLVMBasicBlockRef prev_block = LLVMGetInsertBlock(g->builder);
LLVMValueRef prev_debug_location = LLVMGetCurrentDebugLocation(g->builder);
LLVMPositionBuilderAtEnd(g->builder, entry_block);
ZigLLVMClearCurrentDebugLocation(g->builder);
LLVMTypeRef usize_type_ref = g->builtin_types.entry_usize->type_ref;
// stack_trace.instruction_addresses[stack_trace.index % stack_trace_ptr_count] = return_address;
LLVMValueRef err_ret_trace_ptr = LLVMGetParam(fn_val, 0);
size_t index_field_index = g->stack_trace_type->data.structure.fields[0].gen_index;
LLVMValueRef index_field_ptr = LLVMBuildStructGEP(g->builder, err_ret_trace_ptr, (unsigned)index_field_index, "");
size_t addresses_field_index = g->stack_trace_type->data.structure.fields[1].gen_index;
LLVMValueRef addresses_field_ptr = LLVMBuildStructGEP(g->builder, err_ret_trace_ptr, (unsigned)addresses_field_index, "");
LLVMValueRef index_val = gen_load_untyped(g, index_field_ptr, 0, false, "");
LLVMValueRef modded_val = LLVMBuildURem(g->builder, index_val, LLVMConstInt(usize_type_ref, stack_trace_ptr_count, false), "");
LLVMValueRef address_indices[] = {
LLVMConstNull(usize_type_ref),
modded_val,
};
LLVMValueRef address_slot = LLVMBuildInBoundsGEP(g->builder, addresses_field_ptr, address_indices, 2, "");
LLVMValueRef return_address = LLVMBuildPtrToInt(g->builder, LLVMGetParam(fn_val, 1), usize_type_ref, "");
LLVMValueRef address_value = LLVMBuildPtrToInt(g->builder, return_address, usize_type_ref, "");
gen_store_untyped(g, address_value, address_slot, 0, false);
// stack_trace.index += 1;
LLVMValueRef index_plus_one_val = LLVMBuildAdd(g->builder, index_val, LLVMConstInt(usize_type_ref, 1, false), "");
gen_store_untyped(g, index_plus_one_val, index_field_ptr, 0, false);
// return;
LLVMBuildRetVoid(g->builder);
LLVMPositionBuilderAtEnd(g->builder, prev_block);
LLVMSetCurrentDebugLocation(g->builder, prev_debug_location);
g->return_err_fn = fn_val;
return fn_val;
}
static LLVMValueRef get_safety_crash_err_fn(CodeGen *g) {
if (g->safety_crash_err_fn != nullptr)
return g->safety_crash_err_fn;
@ -1053,8 +1127,9 @@ static void gen_debug_safety_crash_for_err(CodeGen *g, LLVMValueRef err_val) {
err_val,
err_ret_trace_val,
};
ZigLLVMBuildCall(g->builder, safety_crash_err_fn, args, 2, get_llvm_cc(g, CallingConventionUnspecified),
LLVMValueRef call_instruction = ZigLLVMBuildCall(g->builder, safety_crash_err_fn, args, 2, get_llvm_cc(g, CallingConventionUnspecified),
ZigLLVM_FnInlineAuto, "");
LLVMSetTailCall(call_instruction, true);
LLVMBuildUnreachable(g->builder);
}
@ -1346,36 +1421,19 @@ static LLVMValueRef ir_render_return(CodeGen *g, IrExecutable *executable, IrIns
is_err_return = true;
}
if (is_err_return) {
LLVMTypeRef usize_type_ref = g->builtin_types.entry_usize->type_ref;
// stack_trace.instruction_addresses[stack_trace.index % stack_trace_ptr_count] = @instructionPointer();
// stack_trace.index += 1;
LLVMBasicBlockRef return_block = LLVMAppendBasicBlock(g->cur_fn_val, "ReturnError");
LLVMValueRef block_address = LLVMBlockAddress(g->cur_fn_val, return_block);
size_t index_field_index = g->stack_trace_type->data.structure.fields[0].gen_index;
LLVMValueRef index_field_ptr = LLVMBuildStructGEP(g->builder, g->cur_err_ret_trace_val, (unsigned)index_field_index, "");
size_t addresses_field_index = g->stack_trace_type->data.structure.fields[1].gen_index;
LLVMValueRef addresses_field_ptr = LLVMBuildStructGEP(g->builder, g->cur_err_ret_trace_val, (unsigned)addresses_field_index, "");
// stack_trace.instruction_addresses[stack_trace.index % stack_trace_ptr_count] = @instructionPointer();
LLVMValueRef index_val = gen_load_untyped(g, index_field_ptr, 0, false, "");
LLVMValueRef modded_val = LLVMBuildURem(g->builder, index_val, LLVMConstInt(usize_type_ref, stack_trace_ptr_count, false), "");
LLVMValueRef address_indices[] = {
LLVMConstNull(usize_type_ref),
modded_val,
LLVMValueRef return_err_fn = get_return_err_fn(g);
LLVMValueRef args[] = {
g->cur_err_ret_trace_val,
block_address,
};
LLVMValueRef address_slot = LLVMBuildInBoundsGEP(g->builder, addresses_field_ptr, address_indices, 2, "");
LLVMValueRef address_value = LLVMBuildPtrToInt(g->builder, block_address, usize_type_ref, "");
gen_store_untyped(g, address_value, address_slot, 0, false);
// stack_trace.index += 1;
LLVMValueRef index_plus_one_val = LLVMBuildAdd(g->builder, index_val, LLVMConstInt(usize_type_ref, 1, false), "");
gen_store_untyped(g, index_plus_one_val, index_field_ptr, 0, false);
LLVMBuildBr(g->builder, return_block);
LLVMPositionBuilderAtEnd(g->builder, return_block);
LLVMValueRef call_instruction = ZigLLVMBuildCall(g->builder, return_err_fn, args, 2,
get_llvm_cc(g, CallingConventionUnspecified), ZigLLVM_FnInlineAuto, "");
LLVMSetTailCall(call_instruction, true);
}
if (handle_is_ptr(return_type)) {
if (calling_convention_does_first_arg_return(g->cur_fn->type_entry->data.fn.fn_type_id.cc)) {