llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-lldb
Author: Michael Buch (Michael137)
<details>
<summary>Changes</summary>
This patch adds a frame recognizer for Clang's
`__builtin_verbose_trap`, which behaves like a
`__builtin_trap`, but emits a failure-reason string into debug-info in order
for debuggers to display
it to a user.
The frame recognizer triggers when we encounter
a frame with a function name that begins with
`__llvm_verbose_trap`, which is the magic prefix
Clang emits into debug-info for verbose traps.
Once such frame is encountered we display the
frame function name as the `Stop Reason` and display that frame to the user.
Example output:
```
(lldb) run
warning: a.out was compiled with optimization - stepping may behave oddly;
variables may not be available.
Process 35942 launched: 'a.out' (arm64)
Process 35942 stopped
* thread #<!-- -->1, queue = 'com.apple.main-thread', stop reason =
__llvm_verbose_trap: Function is not implemented
frame #<!-- -->1: 0x0000000100003fa4 a.out`main [inlined]
Dummy::func(this=<unavailable>) at verbose_trap.cpp:3:5 [opt]
1 struct Dummy {
2 void func() {
-> 3 __builtin_verbose_trap("Function is not implemented");
4 }
5 };
6
7 int main() {
(lldb) bt
* thread #<!-- -->1, queue = 'com.apple.main-thread', stop reason =
__llvm_verbose_trap: Function is not implemented
frame #<!-- -->0: 0x0000000100003fa4 a.out`main [inlined]
__llvm_verbose_trap: Function is not implemented at verbose_trap.cpp:0 [opt]
* frame #<!-- -->1: 0x0000000100003fa4 a.out`main [inlined]
Dummy::func(this=<unavailable>) at verbose_trap.cpp:3:5 [opt]
frame #<!-- -->2: 0x0000000100003fa4 a.out`main at verbose_trap.cpp:8:13
[opt]
frame #<!-- -->3: 0x0000000189d518b4 dyld`start + 1988
```
---
Full diff: https://github.com/llvm/llvm-project/pull/80368.diff
6 Files Affected:
- (added) lldb/include/lldb/Target/VerboseTrapFrameRecognizer.h (+39)
- (modified) lldb/source/Target/CMakeLists.txt (+1)
- (modified) lldb/source/Target/Process.cpp (+2)
- (added) lldb/source/Target/VerboseTrapFrameRecognizer.cpp (+85)
- (added) lldb/test/Shell/Recognizer/Inputs/verbose_trap.cpp (+8)
- (added) lldb/test/Shell/Recognizer/verbose_trap.test (+9)
``````````diff
diff --git a/lldb/include/lldb/Target/VerboseTrapFrameRecognizer.h
b/lldb/include/lldb/Target/VerboseTrapFrameRecognizer.h
new file mode 100644
index 0000000000000..7e045760a28be
--- /dev/null
+++ b/lldb/include/lldb/Target/VerboseTrapFrameRecognizer.h
@@ -0,0 +1,39 @@
+#ifndef LLDB_TARGET_VERBOSETRAPFRAMERECOGNIZER_H
+#define LLDB_TARGET_VERBOSETRAPFRAMERECOGNIZER_H
+
+#include "lldb/Target/StackFrameRecognizer.h"
+
+namespace lldb_private {
+
+void RegisterVerboseTrapFrameRecognizer(Process &process);
+
+/// Holds the stack frame that caused the Verbose trap and the inlined stop
+/// reason message.
+class VerboseTrapRecognizedStackFrame : public RecognizedStackFrame {
+public:
+ VerboseTrapRecognizedStackFrame(lldb::StackFrameSP most_relevant_frame_sp,
+ std::string stop_desc);
+
+ lldb::StackFrameSP GetMostRelevantFrame() override;
+
+private:
+ lldb::StackFrameSP m_most_relevant_frame;
+};
+
+/// When a thread stops, it checks the current frame contains a
+/// Verbose Trap diagnostic. If so, it returns a \a
+/// VerboseTrapRecognizedStackFrame holding the diagnostic a stop reason
+/// description with and the parent frame as the most relavant frame.
+class VerboseTrapFrameRecognizer : public StackFrameRecognizer {
+public:
+ std::string GetName() override {
+ return "Verbose Trap StackFrame Recognizer";
+ }
+
+ lldb::RecognizedStackFrameSP
+ RecognizeFrame(lldb::StackFrameSP frame) override;
+};
+
+} // namespace lldb_private
+
+#endif // LLDB_TARGET_VERBOSETRAPFRAMERECOGNIZER_H
diff --git a/lldb/source/Target/CMakeLists.txt
b/lldb/source/Target/CMakeLists.txt
index cf4818eae3eb8..8186ccbea27d4 100644
--- a/lldb/source/Target/CMakeLists.txt
+++ b/lldb/source/Target/CMakeLists.txt
@@ -78,6 +78,7 @@ add_lldb_library(lldbTarget
UnixSignals.cpp
UnwindAssembly.cpp
UnwindLLDB.cpp
+ VerboseTrapFrameRecognizer.cpp
LINK_LIBS
lldbBreakpoint
diff --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index 23a8a66645c02..04b00aaa1fac9 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -63,6 +63,7 @@
#include "lldb/Target/ThreadPlanCallFunction.h"
#include "lldb/Target/ThreadPlanStack.h"
#include "lldb/Target/UnixSignals.h"
+#include "lldb/Target/VerboseTrapFrameRecognizer.h"
#include "lldb/Utility/Event.h"
#include "lldb/Utility/LLDBLog.h"
#include "lldb/Utility/Log.h"
@@ -497,6 +498,7 @@ Process::Process(lldb::TargetSP target_sp, ListenerSP
listener_sp,
value_sp->SetValueAs(platform_cache_line_size);
RegisterAssertFrameRecognizer(this);
+ RegisterVerboseTrapFrameRecognizer(*this);
}
Process::~Process() {
diff --git a/lldb/source/Target/VerboseTrapFrameRecognizer.cpp
b/lldb/source/Target/VerboseTrapFrameRecognizer.cpp
new file mode 100644
index 0000000000000..d1a9ec18f8fe4
--- /dev/null
+++ b/lldb/source/Target/VerboseTrapFrameRecognizer.cpp
@@ -0,0 +1,85 @@
+#include "lldb/Target/VerboseTrapFrameRecognizer.h"
+
+#include "lldb/Core/Module.h"
+#include "lldb/Symbol/Function.h"
+#include "lldb/Symbol/SymbolContext.h"
+#include "lldb/Target/Process.h"
+#include "lldb/Target/Target.h"
+
+#include "lldb/Utility/LLDBLog.h"
+#include "lldb/Utility/Log.h"
+
+using namespace llvm;
+using namespace lldb;
+using namespace lldb_private;
+
+VerboseTrapRecognizedStackFrame::VerboseTrapRecognizedStackFrame(
+ StackFrameSP most_relevant_frame_sp, std::string stop_desc)
+ : m_most_relevant_frame(most_relevant_frame_sp) {
+ m_stop_desc = std::move(stop_desc);
+}
+
+lldb::RecognizedStackFrameSP
+VerboseTrapFrameRecognizer::RecognizeFrame(lldb::StackFrameSP frame_sp) {
+ if (frame_sp->GetFrameIndex())
+ return {};
+
+ ThreadSP thread_sp = frame_sp->GetThread();
+ ProcessSP process_sp = thread_sp->GetProcess();
+
+ StackFrameSP most_relevant_frame_sp = thread_sp->GetStackFrameAtIndex(1);
+
+ if (!most_relevant_frame_sp) {
+ Log *log = GetLog(LLDBLog::Unwind);
+ LLDB_LOG(
+ log,
+ "Failed to find most relevant frame: Hit unwinding bound (1 frame)!");
+ return {};
+ }
+
+ SymbolContext sc = frame_sp->GetSymbolContext(eSymbolContextEverything);
+
+ if (!sc.block)
+ return {};
+
+ // The runtime error is set as the function name in the inlined function info
+ // of frame #0 by the compiler
+ const InlineFunctionInfo *inline_info = nullptr;
+ Block *inline_block = sc.block->GetContainingInlinedBlock();
+
+ if (!inline_block)
+ return {};
+
+ inline_info = sc.block->GetInlinedFunctionInfo();
+
+ if (!inline_info)
+ return {};
+
+ auto runtime_error = inline_info->GetName().GetString();
+
+ if (runtime_error.empty())
+ return {};
+
+ return lldb::RecognizedStackFrameSP(new VerboseTrapRecognizedStackFrame(
+ most_relevant_frame_sp, std::move(runtime_error)));
+}
+
+lldb::StackFrameSP VerboseTrapRecognizedStackFrame::GetMostRelevantFrame() {
+ return m_most_relevant_frame;
+}
+
+namespace lldb_private {
+
+void RegisterVerboseTrapFrameRecognizer(Process &process) {
+ RegularExpressionSP module_regex_sp = nullptr;
+ RegularExpressionSP symbol_regex_sp(
+ new RegularExpression("(__llvm_verbose_trap)"));
+
+ StackFrameRecognizerSP srf_recognizer_sp =
+ std::make_shared<VerboseTrapFrameRecognizer>();
+
+ process.GetTarget().GetFrameRecognizerManager().AddRecognizer(
+ srf_recognizer_sp, module_regex_sp, symbol_regex_sp, false);
+}
+
+} // namespace lldb_private
diff --git a/lldb/test/Shell/Recognizer/Inputs/verbose_trap.cpp
b/lldb/test/Shell/Recognizer/Inputs/verbose_trap.cpp
new file mode 100644
index 0000000000000..6867c245e2fc9
--- /dev/null
+++ b/lldb/test/Shell/Recognizer/Inputs/verbose_trap.cpp
@@ -0,0 +1,8 @@
+struct Dummy {
+ void func() { __builtin_verbose_trap("Function is not implemented"); }
+};
+
+int main() {
+ Dummy{}.func();
+ return 0;
+}
diff --git a/lldb/test/Shell/Recognizer/verbose_trap.test
b/lldb/test/Shell/Recognizer/verbose_trap.test
new file mode 100644
index 0000000000000..7790354784afd
--- /dev/null
+++ b/lldb/test/Shell/Recognizer/verbose_trap.test
@@ -0,0 +1,9 @@
+# RUN: %clang_host -g -O0 %S/Inputs/verbose_trap.cpp -o %t.out
+# RUN: %lldb -b -s %s %t.out | FileCheck %s
+run
+# CHECK: thread #{{.*}}stop reason = __llvm_verbose_trap: Function is not
implemented
+frame info
+# CHECK: frame #{{.*}}`Dummy::func(this={{.*}}) at verbose_trap.cpp
+frame recognizer info 0
+# CHECK: frame 0 is recognized by Verbose Trap StackFrame Recognizer
+q
``````````
</details>
https://github.com/llvm/llvm-project/pull/80368
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