[Lldb-commits] [lldb] 4346318 - [LLDB] Recognize `std::noop_coroutine()` in `std::coroutine_handle` pretty printer
Adrian Vogelsgesang via lldb-commits
lldb-commits at lists.llvm.org
Sun Nov 20 11:19:07 PST 2022
Author: Adrian Vogelsgesang
Date: 2022-11-20T11:18:52-08:00
New Revision: 4346318f5c700f4e85f866610fb8328fc429319b
URL: https://github.com/llvm/llvm-project/commit/4346318f5c700f4e85f866610fb8328fc429319b
DIFF: https://github.com/llvm/llvm-project/commit/4346318f5c700f4e85f866610fb8328fc429319b.diff
LOG: [LLDB] Recognize `std::noop_coroutine()` in `std::coroutine_handle` pretty printer
With this commit, the `std::coroutine_handle` pretty printer now
recognizes `std::noop_coroutine()` handles. For noop coroutine handles,
we identify use the summary string `noop_coroutine` and we don't print
children
Instead of
```
(std::coroutine_handle<void>) $3 = coro frame = 0x555555559058 {
resume = 0x00005555555564f0 (a.out`std::__1::coroutine_handle<std::__1::noop_coroutine_promise>::__noop_coroutine_frame_ty_::__dummy_resume_destroy_func() at noop_coroutine_handle.h:79)
destroy = 0x00005555555564f0 (a.out`std::__1::coroutine_handle<std::__1::noop_coroutine_promise>::__noop_coroutine_frame_ty_::__dummy_resume_destroy_func() at noop_coroutine_handle.h:79)
}
```
we now print
```
(std::coroutine_handle<void>) $3 = noop_coroutine
```
Differential Revision: https://reviews.llvm.org/D132735
Added:
Modified:
lldb/source/Plugins/Language/CPlusPlus/Coroutines.cpp
lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/coroutine_handle/TestCoroutineHandle.py
lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/coroutine_handle/main.cpp
Removed:
################################################################################
diff --git a/lldb/source/Plugins/Language/CPlusPlus/Coroutines.cpp b/lldb/source/Plugins/Language/CPlusPlus/Coroutines.cpp
index bd9ff99db67b8..aa6a6ef7e56ae 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/Coroutines.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/Coroutines.cpp
@@ -35,7 +35,7 @@ static ValueObjectSP GetCoroFramePtrFromHandle(ValueObject &valobj) {
return ptr_sp;
}
-static Function *ExtractDestroyFunction(ValueObjectSP &frame_ptr_sp) {
+static Function *ExtractFunction(ValueObjectSP &frame_ptr_sp, int offset) {
lldb::TargetSP target_sp = frame_ptr_sp->GetTargetSP();
lldb::ProcessSP process_sp = frame_ptr_sp->GetProcessSP();
auto ptr_size = process_sp->GetAddressByteSize();
@@ -47,24 +47,64 @@ static Function *ExtractDestroyFunction(ValueObjectSP &frame_ptr_sp) {
lldbassert(addr_type == AddressType::eAddressTypeLoad);
Status error;
- // The destroy pointer is the 2nd pointer inside the compiler-generated
- // `pair<resumePtr,destroyPtr>`.
- auto destroy_func_ptr_addr = frame_ptr_addr + ptr_size;
- lldb::addr_t destroy_func_addr =
- process_sp->ReadPointerFromMemory(destroy_func_ptr_addr, error);
+ auto func_ptr_addr = frame_ptr_addr + offset * ptr_size;
+ lldb::addr_t func_addr =
+ process_sp->ReadPointerFromMemory(func_ptr_addr, error);
if (error.Fail())
return nullptr;
- Address destroy_func_address;
- if (!target_sp->ResolveLoadAddress(destroy_func_addr, destroy_func_address))
+ Address func_address;
+ if (!target_sp->ResolveLoadAddress(func_addr, func_address))
return nullptr;
- Function *destroy_func =
- destroy_func_address.CalculateSymbolContextFunction();
- if (!destroy_func)
- return nullptr;
+ return func_address.CalculateSymbolContextFunction();
+}
+
+static Function *ExtractResumeFunction(ValueObjectSP &frame_ptr_sp) {
+ return ExtractFunction(frame_ptr_sp, 0);
+}
+
+static Function *ExtractDestroyFunction(ValueObjectSP &frame_ptr_sp) {
+ return ExtractFunction(frame_ptr_sp, 1);
+}
+
+static bool IsNoopCoroFunction(Function *f) {
+ if (!f)
+ return false;
- return destroy_func;
+ // clang's `__builtin_coro_noop` gets lowered to
+ // `_NoopCoro_ResumeDestroy`. This is used by libc++
+ // on clang.
+ auto mangledName = f->GetMangled().GetMangledName();
+ if (mangledName == "__NoopCoro_ResumeDestroy")
+ return true;
+
+ // libc++ uses the following name as a fallback on
+ // compilers without `__builtin_coro_noop`.
+ auto name = f->GetNameNoArguments();
+ static RegularExpression libcxxRegex(
+ "^std::coroutine_handle<std::noop_coroutine_promise>::"
+ "__noop_coroutine_frame_ty_::__dummy_resume_destroy_func$");
+ lldbassert(libcxxRegex.IsValid());
+ if (libcxxRegex.Execute(name.GetStringRef()))
+ return true;
+ static RegularExpression libcxxRegexAbiNS(
+ "^std::__[[:alnum:]]+::coroutine_handle<std::__[[:alnum:]]+::"
+ "noop_coroutine_promise>::__noop_coroutine_frame_ty_::"
+ "__dummy_resume_destroy_func$");
+ lldbassert(libcxxRegexAbiNS.IsValid());
+ if (libcxxRegexAbiNS.Execute(name.GetStringRef()))
+ return true;
+
+ // libstdc++ uses the following name on both gcc and clang.
+ static RegularExpression libstdcppRegex(
+ "^std::__[[:alnum:]]+::coroutine_handle<std::__[[:alnum:]]+::"
+ "noop_coroutine_promise>::__frame::__dummy_resume_destroy$");
+ lldbassert(libstdcppRegex.IsValid());
+ if (libstdcppRegex.Execute(name.GetStringRef()))
+ return true;
+
+ return false;
}
static CompilerType InferPromiseType(Function &destroy_func) {
@@ -113,9 +153,15 @@ bool lldb_private::formatters::StdlibCoroutineHandleSummaryProvider(
if (!ptr_sp->GetValueAsUnsigned(0)) {
stream << "nullptr";
- } else {
- stream.Printf("coro frame = 0x%" PRIx64, ptr_sp->GetValueAsUnsigned(0));
+ return true;
}
+ if (IsNoopCoroFunction(ExtractResumeFunction(ptr_sp)) &&
+ IsNoopCoroFunction(ExtractDestroyFunction(ptr_sp))) {
+ stream << "noop_coroutine";
+ return true;
+ }
+
+ stream.Printf("coro frame = 0x%" PRIx64, ptr_sp->GetValueAsUnsigned(0));
return true;
}
@@ -158,6 +204,14 @@ bool lldb_private::formatters::StdlibCoroutineHandleSyntheticFrontEnd::
if (!ptr_sp)
return false;
+ Function *resume_func = ExtractResumeFunction(ptr_sp);
+ Function *destroy_func = ExtractDestroyFunction(ptr_sp);
+
+ if (IsNoopCoroFunction(resume_func) && IsNoopCoroFunction(destroy_func)) {
+ // For `std::noop_coroutine()`, we don't want to display any child nodes.
+ return false;
+ }
+
// Get the `promise_type` from the template argument
CompilerType promise_type(
valobj_sp->GetCompilerType().GetTypeTemplateArgument(0));
@@ -169,12 +223,10 @@ bool lldb_private::formatters::StdlibCoroutineHandleSyntheticFrontEnd::
auto ast_ctx = ts.dyn_cast_or_null<TypeSystemClang>();
if (!ast_ctx)
return false;
- if (promise_type.IsVoidType()) {
- if (Function *destroy_func = ExtractDestroyFunction(ptr_sp)) {
- if (CompilerType inferred_type = InferPromiseType(*destroy_func)) {
- // Copy the type over to the correct `TypeSystemClang` instance
- promise_type = m_ast_importer->CopyType(*ast_ctx, inferred_type);
- }
+ if (promise_type.IsVoidType() && destroy_func) {
+ if (CompilerType inferred_type = InferPromiseType(*destroy_func)) {
+ // Copy the type over to the correct `TypeSystemClang` instance
+ promise_type = m_ast_importer->CopyType(*ast_ctx, inferred_type);
}
}
diff --git a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/coroutine_handle/TestCoroutineHandle.py b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/coroutine_handle/TestCoroutineHandle.py
index 44e5e6451c10d..d1b4d59de5f5f 100644
--- a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/coroutine_handle/TestCoroutineHandle.py
+++ b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/coroutine_handle/TestCoroutineHandle.py
@@ -38,6 +38,13 @@ def do_test(self, stdlib_type):
ValueCheck(name="current_value", value = "-1"),
])
])
+ # We recognize and pretty-print `std::noop_coroutine`. We don't display
+ # any children as those are irrelevant for the noop coroutine.
+ # clang version < 16 did not yet write debug info for the noop coroutines.
+ if not (is_clang and self.expectedCompilerVersion(["<", "16"])):
+ self.expect_expr("noop_hdl",
+ result_summary="noop_coroutine",
+ result_children=[])
if is_clang:
# For a type-erased `coroutine_handle<>`, we can still devirtualize
# the promise call and display the correctly typed promise.
diff --git a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/coroutine_handle/main.cpp b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/coroutine_handle/main.cpp
index 8cb81c3bc9f4c..e34637f09f6ed 100644
--- a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/coroutine_handle/main.cpp
+++ b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/coroutine_handle/main.cpp
@@ -45,6 +45,7 @@ int main() {
std::coroutine_handle<> type_erased_hdl = gen.hdl;
std::coroutine_handle<int> incorrectly_typed_hdl =
std::coroutine_handle<int>::from_address(gen.hdl.address());
+ std::coroutine_handle<> noop_hdl = std::noop_coroutine();
gen.hdl.resume(); // Break at initial_suspend
gen.hdl.resume(); // Break after co_yield
empty_function_so_we_can_set_a_breakpoint(); // Break at final_suspend
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