authorgravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2019-08-05 03:10:14-04:00
committergravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2019-08-05 03:10:14-04:00
log20f63e588e62c4a7250bc96c9e5b54c8106ad1af
treebc138766dfe7938b12891e3856e2cab3a4eece26
parentdfe8c5a2e9b1778c1911e987c9286d05db307fe7
signaturelock-open Commit is signed but in an unrecognized format.

async functions have error return traces where appropriate

however the traces are not merged on `await` or async function calls yet. When an async function has an error set or error union as its return type, it has a `StackTrace` before the args in the frame, so that it is accessible from `anyframe->T` awaiters. However when it does not have an errorable return type, but it does call or await an errorable, it has a stack trace just before the locals. This way when doing an `@asyncCall` on an async function pointer, it can populate the args (which are after the `StackTrace`) because it knows the offset of the args based only on the return type. This sort of matches normal functions, where a stack trace pointer could be supplied by a parameter, or it could be supplied by the stack of the function, depending on whether the function itself is errorable.

6 files changed, 91 insertions(+), 70 deletions(-)

BRANCH_TODO+1-1
......@@ -1,5 +1,5 @@
1 * error return tracing - handle `await` and function calls
12 * go over the commented out tests
2 * error return tracing
33 * compile error for error: expected anyframe->T, found 'anyframe'
44 * compile error for error: expected anyframe->T, found 'i32'
55 * await of a non async function
src/analyze.cpp+14-14
......@@ -5230,9 +5230,8 @@ static Error resolve_coro_frame(CodeGen *g, ZigType *frame_type) {
52305230 field_names.append("@result");
52315231 field_types.append(fn_type_id->return_type);
52325232
5233 if (codegen_fn_has_err_ret_tracing(g, fn_type_id->return_type)) {
5234 field_names.append("@ptr_stack_trace");
5235 field_types.append(get_ptr_to_stack_trace_type(g));
5233 if (codegen_fn_has_err_ret_tracing_arg(g, fn_type_id->return_type)) {
5234 (void)get_ptr_to_stack_trace_type(g); // populate g->stack_trace_type
52365235
52375236 field_names.append("@stack_trace");
52385237 field_types.append(g->stack_trace_type);
......@@ -5256,6 +5255,16 @@ static Error resolve_coro_frame(CodeGen *g, ZigType *frame_type) {
52565255 field_types.append(param_type);
52575256 }
52585257
5258 if (codegen_fn_has_err_ret_tracing_stack(g, fn)) {
5259 (void)get_ptr_to_stack_trace_type(g); // populate g->stack_trace_type
5260
5261 field_names.append("@stack_trace");
5262 field_types.append(g->stack_trace_type);
5263
5264 field_names.append("@instruction_addresses");
5265 field_types.append(get_array_type(g, g->builtin_types.entry_usize, stack_trace_ptr_count));
5266 }
5267
52595268 for (size_t alloca_i = 0; alloca_i < fn->alloca_gen_list.length; alloca_i += 1) {
52605269 IrInstructionAllocaGen *instruction = fn->alloca_gen_list.at(alloca_i);
52615270 ZigType *ptr_type = instruction->base.value.type;
......@@ -7563,8 +7572,7 @@ static void resolve_llvm_types_any_frame(CodeGen *g, ZigType *any_frame_type, Re
75637572 if (have_result_type) {
75647573 field_types.append(get_llvm_type(g, ptr_result_type)); // ptr_result
75657574 field_types.append(get_llvm_type(g, result_type)); // result
7566 if (codegen_fn_has_err_ret_tracing(g, result_type)) {
7567 field_types.append(get_llvm_type(g, get_ptr_to_stack_trace_type(g))); // ptr_stack_trace
7575 if (codegen_fn_has_err_ret_tracing_arg(g, result_type)) {
75687576 field_types.append(get_llvm_type(g, g->stack_trace_type)); // stack_trace
75697577 field_types.append(get_llvm_type(g, get_array_type(g, g->builtin_types.entry_usize, stack_trace_ptr_count))); // instruction_addresses
75707578 }
......@@ -7614,15 +7622,7 @@ static void resolve_llvm_types_any_frame(CodeGen *g, ZigType *any_frame_type, Re
76147622 8*LLVMOffsetOfElement(g->target_data_ref, frame_header_type, di_element_types.length),
76157623 ZigLLVM_DIFlags_Zero, get_llvm_di_type(g, result_type)));
76167624
7617 if (codegen_fn_has_err_ret_tracing(g, result_type)) {
7618 di_element_types.append(
7619 ZigLLVMCreateDebugMemberType(g->dbuilder,
7620 ZigLLVMTypeToScope(any_frame_type->llvm_di_type), "ptr_stack_trace",
7621 di_file, line,
7622 8*LLVMABISizeOfType(g->target_data_ref, field_types.at(di_element_types.length)),
7623 8*LLVMABIAlignmentOfType(g->target_data_ref, field_types.at(di_element_types.length)),
7624 8*LLVMOffsetOfElement(g->target_data_ref, frame_header_type, di_element_types.length),
7625 ZigLLVM_DIFlags_Zero, get_llvm_di_type(g, get_ptr_to_stack_trace_type(g))));
7625 if (codegen_fn_has_err_ret_tracing_arg(g, result_type)) {
76267626 di_element_types.append(
76277627 ZigLLVMCreateDebugMemberType(g->dbuilder,
76287628 ZigLLVMTypeToScope(any_frame_type->llvm_di_type), "stack_trace",
src/codegen.cpp+61-44
......@@ -298,7 +298,7 @@ static LLVMLinkage to_llvm_linkage(GlobalLinkageId id) {
298298}
299299
300300// label (grep this): [coro_frame_struct_layout]
301static uint32_t frame_index_trace(CodeGen *g, FnTypeId *fn_type_id) {
301static uint32_t frame_index_trace_arg(CodeGen *g, FnTypeId *fn_type_id) {
302302 // [0] *ReturnType
303303 // [1] ReturnType
304304 uint32_t return_field_count = type_has_bits(fn_type_id->return_type) ? 2 : 0;
......@@ -307,14 +307,25 @@ static uint32_t frame_index_trace(CodeGen *g, FnTypeId *fn_type_id) {
307307
308308// label (grep this): [coro_frame_struct_layout]
309309static uint32_t frame_index_arg(CodeGen *g, FnTypeId *fn_type_id) {
310 bool have_stack_trace = g->have_err_ret_tracing && codegen_fn_has_err_ret_tracing(g, fn_type_id->return_type);
311 // [0] *StackTrace
312 // [1] StackTrace
313 // [2] [stack_trace_ptr_count]usize
314 uint32_t trace_field_count = have_stack_trace ? 3 : 0;
315 return frame_index_trace(g, fn_type_id) + trace_field_count;
310 bool have_stack_trace = codegen_fn_has_err_ret_tracing_arg(g, fn_type_id->return_type);
311 // [0] StackTrace
312 // [1] [stack_trace_ptr_count]usize
313 uint32_t trace_field_count = have_stack_trace ? 2 : 0;
314 return frame_index_trace_arg(g, fn_type_id) + trace_field_count;
316315}
317316
317// label (grep this): [coro_frame_struct_layout]
318static uint32_t frame_index_trace_stack(CodeGen *g, FnTypeId *fn_type_id) {
319 uint32_t result = frame_index_arg(g, fn_type_id);
320 for (size_t i = 0; i < fn_type_id->param_count; i += 1) {
321 if (type_has_bits(fn_type_id->param_info->type)) {
322 result += 1;
323 }
324 }
325 return result;
326}
327
328
318329static uint32_t get_err_ret_trace_arg_index(CodeGen *g, ZigFn *fn_table_entry) {
319330 if (!g->have_err_ret_tracing) {
320331 return UINT32_MAX;
......@@ -1287,9 +1298,6 @@ static LLVMValueRef get_cur_err_ret_trace_val(CodeGen *g, Scope *scope) {
12871298 if (!g->have_err_ret_tracing) {
12881299 return nullptr;
12891300 }
1290 if (fn_is_async(g->cur_fn)) {
1291 return LLVMBuildLoad(g->builder, g->cur_err_ret_trace_val_arg, "");
1292 }
12931301 if (g->cur_err_ret_trace_val_stack != nullptr) {
12941302 return g->cur_err_ret_trace_val_stack;
12951303 }
......@@ -3441,6 +3449,10 @@ static void render_async_spills(CodeGen *g) {
34413449 gen_var_debug_decl(g, var);
34423450 }
34433451 }
3452 // label (grep this): [coro_frame_struct_layout]
3453 if (codegen_fn_has_err_ret_tracing_stack(g, g->cur_fn)) {
3454 async_var_index += 2;
3455 }
34443456 for (size_t alloca_i = 0; alloca_i < g->cur_fn->alloca_gen_list.length; alloca_i += 1) {
34453457 IrInstructionAllocaGen *instruction = g->cur_fn->alloca_gen_list.at(alloca_i);
34463458 ZigType *ptr_type = instruction->base.value.type;
......@@ -3525,7 +3537,7 @@ static LLVMValueRef ir_render_call(CodeGen *g, IrExecutable *executable, IrInstr
35253537 CallingConvention cc = fn_type->data.fn.fn_type_id.cc;
35263538
35273539 bool first_arg_ret = ret_has_bits && want_first_arg_sret(g, fn_type_id);
3528 bool prefix_arg_err_ret_stack = codegen_fn_has_err_ret_tracing(g, fn_type_id->return_type);
3540 bool prefix_arg_err_ret_stack = codegen_fn_has_err_ret_tracing_arg(g, fn_type_id->return_type);
35293541 bool is_var_args = fn_type_id->is_var_args;
35303542 ZigList<LLVMValueRef> gen_param_values = {};
35313543 LLVMValueRef result_loc = instruction->result_loc ? ir_llvm_value(g, instruction->result_loc) : nullptr;
......@@ -3572,28 +3584,8 @@ static LLVMValueRef ir_render_call(CodeGen *g, IrExecutable *executable, IrInstr
35723584 }
35733585 }
35743586
3575 if (prefix_arg_err_ret_stack) {
3576 uint32_t trace_field_index = frame_index_trace(g, fn_type_id);
3577 LLVMValueRef trace_field_ptr_ptr = LLVMBuildStructGEP(g->builder, frame_result_loc,
3578 trace_field_index, "");
3579 LLVMValueRef trace_field_ptr = LLVMBuildStructGEP(g->builder, frame_result_loc,
3580 trace_field_index + 1, "");
3581 LLVMValueRef trace_field_addrs = LLVMBuildStructGEP(g->builder, frame_result_loc,
3582 trace_field_index + 2, "");
3583 LLVMBuildStore(g->builder, trace_field_ptr, trace_field_ptr_ptr);
3584
3585 LLVMValueRef index_ptr = LLVMBuildStructGEP(g->builder, trace_field_ptr, 0, "");
3586 LLVMBuildStore(g->builder, zero, index_ptr);
3587
3588 LLVMValueRef addrs_slice_ptr = LLVMBuildStructGEP(g->builder, trace_field_ptr, 1, "");
3589 LLVMValueRef addrs_ptr_ptr = LLVMBuildStructGEP(g->builder, addrs_slice_ptr, slice_ptr_index, "");
3590 LLVMValueRef indices[] = { LLVMConstNull(usize_type_ref), LLVMConstNull(usize_type_ref) };
3591 LLVMValueRef trace_field_addrs_as_ptr = LLVMBuildInBoundsGEP(g->builder, trace_field_addrs, indices, 2, "");
3592 LLVMBuildStore(g->builder, trace_field_addrs_as_ptr, addrs_ptr_ptr);
3593
3594 LLVMValueRef addrs_len_ptr = LLVMBuildStructGEP(g->builder, addrs_slice_ptr, slice_len_index, "");
3595 LLVMBuildStore(g->builder, LLVMConstInt(usize_type_ref, stack_trace_ptr_count, false), addrs_len_ptr);
3596 }
3587 // even if prefix_arg_err_ret_stack is true, let the async function do its own
3588 // initialization.
35973589 } else if (callee_is_async) {
35983590 frame_result_loc = ir_llvm_value(g, instruction->frame_result_loc);
35993591 awaiter_init_val = LLVMBuildPtrToInt(g->builder, g->cur_ret_ptr, usize_type_ref, ""); // caller's own frame pointer
......@@ -3607,13 +3599,8 @@ static LLVMValueRef ir_render_call(CodeGen *g, IrExecutable *executable, IrInstr
36073599 }
36083600 }
36093601
3610 if (prefix_arg_err_ret_stack) {
3611 uint32_t trace_field_index = frame_index_trace(g, fn_type_id);
3612 LLVMValueRef trace_field_ptr = LLVMBuildStructGEP(g->builder, frame_result_loc, trace_field_index, "");
3613 LLVMValueRef err_trace_val = get_cur_err_ret_trace_val(g, instruction->base.scope);
3614 LLVMBuildStore(g->builder, err_trace_val, trace_field_ptr);
3615 }
3616
3602 // even if prefix_arg_err_ret_stack is true, let the async function do its
3603 // error return tracing normally, and then we'll invoke merge_error_return_traces like normal.
36173604 }
36183605 if (instruction->is_async || callee_is_async) {
36193606 assert(frame_result_loc != nullptr);
......@@ -6790,9 +6777,16 @@ static void do_code_gen(CodeGen *g) {
67906777 g->cur_async_awaiter_ptr = LLVMBuildStructGEP(g->builder, g->cur_ret_ptr, coro_awaiter_index, "");
67916778 LLVMValueRef resume_index_ptr = LLVMBuildStructGEP(g->builder, g->cur_ret_ptr, coro_resume_index, "");
67926779 g->cur_async_resume_index_ptr = resume_index_ptr;
6793 if (codegen_fn_has_err_ret_tracing(g, fn_type_id->return_type)) {
6794 uint32_t field_index = frame_index_trace(g, fn_type_id);
6795 g->cur_err_ret_trace_val_arg = LLVMBuildStructGEP(g->builder, g->cur_ret_ptr, field_index, "");
6780 LLVMValueRef err_ret_trace_val = nullptr;
6781 uint32_t trace_field_index;
6782 if (codegen_fn_has_err_ret_tracing_arg(g, fn_type_id->return_type)) {
6783 trace_field_index = frame_index_trace_arg(g, fn_type_id);
6784 err_ret_trace_val = LLVMBuildStructGEP(g->builder, g->cur_ret_ptr, trace_field_index, "");
6785 g->cur_err_ret_trace_val_arg = err_ret_trace_val;
6786 } else if (codegen_fn_has_err_ret_tracing_stack(g, fn_table_entry)) {
6787 trace_field_index = frame_index_trace_stack(g, fn_type_id);
6788 err_ret_trace_val = LLVMBuildStructGEP(g->builder, g->cur_ret_ptr, trace_field_index, "");
6789 g->cur_err_ret_trace_val_stack = err_ret_trace_val;
67966790 }
67976791
67986792 LLVMValueRef resume_index = LLVMBuildLoad(g->builder, resume_index_ptr, "");
......@@ -6804,6 +6798,24 @@ static void do_code_gen(CodeGen *g) {
68046798 LLVMAddCase(switch_instr, zero, entry_block->llvm_block);
68056799 g->cur_resume_block_count += 1;
68066800 LLVMPositionBuilderAtEnd(g->builder, entry_block->llvm_block);
6801 if (err_ret_trace_val != nullptr) {
6802 LLVMValueRef trace_field_ptr = LLVMBuildStructGEP(g->builder, g->cur_ret_ptr,
6803 trace_field_index, "");
6804 LLVMValueRef trace_field_addrs = LLVMBuildStructGEP(g->builder, g->cur_ret_ptr,
6805 trace_field_index + 1, "");
6806
6807 LLVMValueRef index_ptr = LLVMBuildStructGEP(g->builder, trace_field_ptr, 0, "");
6808 LLVMBuildStore(g->builder, zero, index_ptr);
6809
6810 LLVMValueRef addrs_slice_ptr = LLVMBuildStructGEP(g->builder, trace_field_ptr, 1, "");
6811 LLVMValueRef addrs_ptr_ptr = LLVMBuildStructGEP(g->builder, addrs_slice_ptr, slice_ptr_index, "");
6812 LLVMValueRef indices[] = { LLVMConstNull(usize_type_ref), LLVMConstNull(usize_type_ref) };
6813 LLVMValueRef trace_field_addrs_as_ptr = LLVMBuildInBoundsGEP(g->builder, trace_field_addrs, indices, 2, "");
6814 LLVMBuildStore(g->builder, trace_field_addrs_as_ptr, addrs_ptr_ptr);
6815
6816 LLVMValueRef addrs_len_ptr = LLVMBuildStructGEP(g->builder, addrs_slice_ptr, slice_len_index, "");
6817 LLVMBuildStore(g->builder, LLVMConstInt(usize_type_ref, stack_trace_ptr_count, false), addrs_len_ptr);
6818 }
68076819 render_async_var_decls(g, entry_block->instruction_list.at(0)->scope);
68086820 } else {
68096821 // create debug variable declarations for parameters
......@@ -9707,8 +9719,13 @@ CodeGen *codegen_create(Buf *main_pkg_path, Buf *root_src_path, const ZigTarget
97079719 return g;
97089720}
97099721
9710bool codegen_fn_has_err_ret_tracing(CodeGen *g, ZigType *return_type) {
9722bool codegen_fn_has_err_ret_tracing_arg(CodeGen *g, ZigType *return_type) {
97119723 return g->have_err_ret_tracing &&
97129724 (return_type->id == ZigTypeIdErrorUnion ||
97139725 return_type->id == ZigTypeIdErrorSet);
97149726}
9727
9728bool codegen_fn_has_err_ret_tracing_stack(CodeGen *g, ZigFn *fn) {
9729 return g->have_err_ret_tracing && fn->calls_or_awaits_errorable_fn &&
9730 !codegen_fn_has_err_ret_tracing_arg(g, fn->type_entry->data.fn.fn_type_id.return_type);
9731}
src/codegen.hpp+2-1
......@@ -61,6 +61,7 @@ Buf *codegen_generate_builtin_source(CodeGen *g);
6161TargetSubsystem detect_subsystem(CodeGen *g);
6262
6363void codegen_release_caches(CodeGen *codegen);
64bool codegen_fn_has_err_ret_tracing(CodeGen *g, ZigType *return_type);
64bool codegen_fn_has_err_ret_tracing_arg(CodeGen *g, ZigType *return_type);
65bool codegen_fn_has_err_ret_tracing_stack(CodeGen *g, ZigFn *fn);
6566
6667#endif
src/ir.cpp+4-3
......@@ -15560,9 +15560,6 @@ static IrInstruction *ir_analyze_fn_call(IrAnalyze *ira, IrInstructionCallSrc *c
1556015560 break;
1556115561 }
1556215562 }
15563 if (call_instruction->is_async) {
15564 zig_panic("TODO async call");
15565 }
1556615563
1556715564 auto existing_entry = ira->codegen->generic_table.put_unique(generic_id, impl_fn);
1556815565 if (existing_entry) {
......@@ -24483,6 +24480,10 @@ static IrInstruction *ir_analyze_instruction_await(IrAnalyze *ira, IrInstruction
2448324480 fn_entry->inferred_async_node = instruction->base.source_node;
2448424481 }
2448524482
24483 if (type_can_fail(result_type)) {
24484 fn_entry->calls_or_awaits_errorable_fn = true;
24485 }
24486
2448624487 IrInstruction *result = ir_build_await(&ira->new_irb,
2448724488 instruction->base.scope, instruction->base.source_node, frame);
2448824489 result->value.type = result_type;
test/stage1/behavior/coroutines.zig+9-7
......@@ -337,19 +337,21 @@ test "async fn with inferred error set" {
337337//test "error return trace across suspend points - early return" {
338338// const p = nonFailing();
339339// resume p;
340// const p2 = try async<allocator> printTrace(p);
341// cancel p2;
340// const p2 = async printTrace(p);
342341//}
343342//
344343//test "error return trace across suspend points - async return" {
345344// const p = nonFailing();
346// const p2 = try async<std.debug.global_allocator> printTrace(p);
345// const p2 = async printTrace(p);
347346// resume p;
348// cancel p2;
349347//}
350348//
351349//fn nonFailing() (anyframe->anyerror!void) {
352// return async<std.debug.global_allocator> suspendThenFail() catch unreachable;
350// const Static = struct {
351// var frame: @Frame(suspendThenFail) = undefined;
352// };
353// Static.frame = async suspendThenFail();
354// return &Static.frame;
353355//}
354356//async fn suspendThenFail() anyerror!void {
355357// suspend;
......@@ -361,8 +363,8 @@ test "async fn with inferred error set" {
361363// if (@errorReturnTrace()) |trace| {
362364// expect(trace.index == 1);
363365// } else switch (builtin.mode) {
364// builtin.Mode.Debug, builtin.Mode.ReleaseSafe => @panic("expected return trace"),
365// builtin.Mode.ReleaseFast, builtin.Mode.ReleaseSmall => {},
366// .Debug, .ReleaseSafe => @panic("expected return trace"),
367// .ReleaseFast, .ReleaseSmall => {},
366368// }
367369// };
368370//}