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chromium / v8 / v8.git / refs/heads/main / . / src / wasm / wasm-debug.cc
blob: 0b53a3967dc53f8ce09f0b73afdb1aaceebe6ce6 [file] [log] [blame]
// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/wasm/wasm-debug.h"
#include <iomanip>
#include <unordered_map>
#include "src/common/assert-scope.h"
#include "src/compiler/wasm-compiler.h"
#include "src/debug/debug-evaluate.h"
#include "src/debug/debug.h"
#include "src/execution/frames-inl.h"
#include "src/heap/factory.h"
#include "src/wasm/baseline/liftoff-compiler.h"
#include "src/wasm/baseline/liftoff-register.h"
#include "src/wasm/compilation-environment-inl.h"
#include "src/wasm/module-decoder.h"
#include "src/wasm/std-object-sizes.h"
#include "src/wasm/value-type.h"
#include "src/wasm/wasm-code-manager.h"
#include "src/wasm/wasm-engine.h"
#include "src/wasm/wasm-limits.h"
#include "src/wasm/wasm-module.h"
#include "src/wasm/wasm-objects-inl.h"
#include "src/wasm/wasm-opcodes-inl.h"
#include "src/wasm/wasm-subtyping.h"
#include "src/wasm/wasm-value.h"
#include "src/zone/accounting-allocator.h"
namespace v8 {
namespace internal {
namespace wasm {
namespace {
using ImportExportKey = std::pair<ImportExportKindCode, uint32_t>;
enum ReturnLocation { kAfterBreakpoint, kAfterWasmCall };
Address FindNewPC(WasmFrame* frame, WasmCode* wasm_code, int byte_offset,
ReturnLocation return_location) {
base::Vector<const uint8_t> new_pos_table = wasm_code->source_positions();
DCHECK_LE(0, byte_offset);
// Find the size of the call instruction by computing the distance from the
// source position entry to the return address.
WasmCode* old_code = frame->wasm_code();
int pc_offset = static_cast<int>(frame->pc() - old_code->instruction_start());
base::Vector<const uint8_t> old_pos_table = old_code->source_positions();
SourcePositionTableIterator old_it(old_pos_table);
int call_offset = -1;
while (!old_it.done() && old_it.code_offset() < pc_offset) {
call_offset = old_it.code_offset();
old_it.Advance();
}
DCHECK_LE(0, call_offset);
int call_instruction_size = pc_offset - call_offset;
// If {return_location == kAfterBreakpoint} we search for the first code
// offset which is marked as instruction (i.e. not the breakpoint).
// If {return_location == kAfterWasmCall} we return the last code offset
// associated with the byte offset.
SourcePositionTableIterator it(new_pos_table);
while (!it.done() && it.source_position().ScriptOffset() != byte_offset) {
it.Advance();
}
if (return_location == kAfterBreakpoint) {
while (!it.is_statement()) it.Advance();
DCHECK_EQ(byte_offset, it.source_position().ScriptOffset());
return wasm_code->instruction_start() + it.code_offset() +
call_instruction_size;
}
DCHECK_EQ(kAfterWasmCall, return_location);
int code_offset;
do {
code_offset = it.code_offset();
it.Advance();
} while (!it.done() && it.source_position().ScriptOffset() == byte_offset);
return wasm_code->instruction_start() + code_offset + call_instruction_size;
}
} // namespace
void DebugSideTable::Print(std::ostream& os) const {
os << "Debug side table (" << num_locals_ << " locals, " << entries_.size()
<< " entries):\n";
for (auto& entry : entries_) entry.Print(os);
os << "\n";
}
void DebugSideTable::Entry::Print(std::ostream& os) const {
os << std::setw(6) << std::hex << pc_offset_ << std::dec << " stack height "
<< stack_height_ << " [";
for (auto& value : changed_values_) {
os << " " << value.type.name() << ":";
switch (value.storage) {
case kConstant:
os << "const#" << value.i32_const;
break;
case kRegister:
os << "reg#" << value.reg_code;
break;
case kStack:
os << "stack#" << value.stack_offset;
break;
}
}
os << " ]\n";
}
size_t DebugSideTable::Entry::EstimateCurrentMemoryConsumption() const {
UPDATE_WHEN_CLASS_CHANGES(DebugSideTable::Entry, 32);
return ContentSize(changed_values_);
}
size_t DebugSideTable::EstimateCurrentMemoryConsumption() const {
UPDATE_WHEN_CLASS_CHANGES(DebugSideTable, 32);
size_t result = sizeof(DebugSideTable) + ContentSize(entries_);
for (const Entry& entry : entries_) {
result += entry.EstimateCurrentMemoryConsumption();
}
return result;
}
class DebugInfoImpl {
public:
explicit DebugInfoImpl(NativeModule* native_module)
: native_module_(native_module) {}
DebugInfoImpl(const DebugInfoImpl&) = delete;
DebugInfoImpl& operator=(const DebugInfoImpl&) = delete;
int GetNumLocals(Address pc, Isolate* isolate) {
FrameInspectionScope scope(this, pc, isolate);
if (!scope.is_inspectable()) return 0;
return scope.debug_side_table->num_locals();
}
WasmValue GetLocalValue(int local, Address pc, Address fp,
Address debug_break_fp, Isolate* isolate) {
FrameInspectionScope scope(this, pc, isolate);
return GetValue(scope.debug_side_table, scope.debug_side_table_entry, local,
fp, debug_break_fp, isolate);
}
int GetStackDepth(Address pc, Isolate* isolate) {
FrameInspectionScope scope(this, pc, isolate);
if (!scope.is_inspectable()) return 0;
int num_locals = scope.debug_side_table->num_locals();
int stack_height = scope.debug_side_table_entry->stack_height();
return stack_height - num_locals;
}
WasmValue GetStackValue(int index, Address pc, Address fp,
Address debug_break_fp, Isolate* isolate) {
FrameInspectionScope scope(this, pc, isolate);
int num_locals = scope.debug_side_table->num_locals();
int value_count = scope.debug_side_table_entry->stack_height();
if (num_locals + index >= value_count) return {};
return GetValue(scope.debug_side_table, scope.debug_side_table_entry,
num_locals + index, fp, debug_break_fp, isolate);
}
const WasmFunction& GetFunctionAtAddress(Address pc, Isolate* isolate) {
FrameInspectionScope scope(this, pc, isolate);
auto* module = native_module_->module();
return module->functions[scope.code->index()];
}
// If the frame position is not in the list of breakpoints, return that
// position. Return 0 otherwise.
// This is used to generate a "dead breakpoint" in Liftoff, which is necessary
// for OSR to find the correct return address.
int DeadBreakpoint(WasmFrame* frame, base::Vector<const int> breakpoints) {
const auto& function =
native_module_->module()->functions[frame->function_index()];
int offset = frame->position() - function.code.offset();
if (std::binary_search(breakpoints.begin(), breakpoints.end(), offset)) {
return 0;
}
return offset;
}
// Find the dead breakpoint (see above) for the top wasm frame, if that frame
// is in the function of the given index.
int DeadBreakpoint(int func_index, base::Vector<const int> breakpoints,
Isolate* isolate) {
DebuggableStackFrameIterator it(isolate);
if (it.done() || !it.is_wasm()) return 0;
auto* wasm_frame = WasmFrame::cast(it.frame());
if (static_cast<int>(wasm_frame->function_index()) != func_index) return 0;
return DeadBreakpoint(wasm_frame, breakpoints);
}
WasmCode* RecompileLiftoffWithBreakpoints(int func_index,
base::Vector<const int> offsets,
int dead_breakpoint) {
DCHECK(!mutex_.TryLock()); // Mutex is held externally.
ForDebugging for_debugging = offsets.size() == 1 && offsets[0] == 0
? kForStepping
: kWithBreakpoints;
// Check the cache first.
for (auto begin = cached_debugging_code_.begin(), it = begin,
end = cached_debugging_code_.end();
it != end; ++it) {
if (it->func_index == func_index &&
it->breakpoint_offsets.as_vector() == offsets &&
it->dead_breakpoint == dead_breakpoint) {
// Rotate the cache entry to the front (for LRU).
for (; it != begin; --it) std::iter_swap(it, it - 1);
if (for_debugging == kWithBreakpoints) {
// Re-install the code, in case it was replaced in the meantime.
native_module_->ReinstallDebugCode(it->code);
}
return it->code;
}
}
// Recompile the function with Liftoff, setting the new breakpoints.
// Not thread-safe. The caller is responsible for locking {mutex_}.
CompilationEnv env = CompilationEnv::ForModule(native_module_);
const WasmFunction* function = &env.module->functions[func_index];
base::Vector<const uint8_t> wire_bytes = native_module_->wire_bytes();
bool is_shared = env.module->types[function->sig_index].is_shared;
FunctionBody body{function->sig, function->code.offset(),
wire_bytes.begin() + function->code.offset(),
wire_bytes.begin() + function->code.end_offset(),
is_shared};
std::unique_ptr<DebugSideTable> debug_sidetable;
// Debug side tables for stepping are generated lazily.
bool generate_debug_sidetable = for_debugging == kWithBreakpoints;
// If lazy validation is on, we might need to lazily validate here.
if (V8_UNLIKELY(!env.module->function_was_validated(func_index))) {
WasmFeatures unused_detected_features;
Zone validation_zone(wasm::GetWasmEngine()->allocator(), ZONE_NAME);
DecodeResult validation_result =
ValidateFunctionBody(&validation_zone, env.enabled_features,
env.module, &unused_detected_features, body);
// Handling illegal modules here is tricky. As lazy validation is off by
// default anyway and this is for debugging only, we just crash for now.
CHECK_WITH_MSG(validation_result.ok(),
validation_result.error().message().c_str());
env.module->set_function_validated(func_index);
}
WasmCompilationResult result = ExecuteLiftoffCompilation(
&env, body,
LiftoffOptions{}
.set_func_index(func_index)
.set_for_debugging(for_debugging)
.set_breakpoints(offsets)
.set_dead_breakpoint(dead_breakpoint)
.set_debug_sidetable(generate_debug_sidetable ? &debug_sidetable
: nullptr));
// Liftoff compilation failure is a FATAL error. We rely on complete Liftoff
// support for debugging.
if (!result.succeeded()) FATAL("Liftoff compilation failed");
DCHECK_EQ(generate_debug_sidetable, debug_sidetable != nullptr);
WasmCode* new_code =
native_module_->PublishCode(native_module_->AddCompiledCode(result));
DCHECK(new_code->is_inspectable());
if (generate_debug_sidetable) {
base::MutexGuard lock(&debug_side_tables_mutex_);
DCHECK_EQ(0, debug_side_tables_.count(new_code));
debug_side_tables_.emplace(new_code, std::move(debug_sidetable));
}
// Insert new code into the cache. Insert before existing elements for LRU.
cached_debugging_code_.insert(
cached_debugging_code_.begin(),
CachedDebuggingCode{func_index, base::OwnedVector<int>::Of(offsets),
dead_breakpoint, new_code});
// Increase the ref count (for the cache entry).
new_code->IncRef();
// Remove exceeding element.
if (cached_debugging_code_.size() > kMaxCachedDebuggingCode) {
// Put the code in the surrounding CodeRefScope to delay deletion until
// after the mutex is released.
WasmCodeRefScope::AddRef(cached_debugging_code_.back().code);
cached_debugging_code_.back().code->DecRefOnLiveCode();
cached_debugging_code_.pop_back();
}
DCHECK_GE(kMaxCachedDebuggingCode, cached_debugging_code_.size());
return new_code;
}
void SetBreakpoint(int func_index, int offset, Isolate* isolate) {
// Put the code ref scope outside of the mutex, so we don't unnecessarily
// hold the mutex while freeing code.
WasmCodeRefScope wasm_code_ref_scope;
// Hold the mutex while modifying breakpoints, to ensure consistency when
// multiple isolates set/remove breakpoints at the same time.
base::MutexGuard guard(&mutex_);
// offset == 0 indicates flooding and should not happen here.
DCHECK_NE(0, offset);
// Get the set of previously set breakpoints, to check later whether a new
// breakpoint was actually added.
std::vector<int> all_breakpoints = FindAllBreakpoints(func_index);
auto& isolate_data = per_isolate_data_[isolate];
std::vector<int>& breakpoints =
isolate_data.breakpoints_per_function[func_index];
auto insertion_point =
std::lower_bound(breakpoints.begin(), breakpoints.end(), offset);
if (insertion_point != breakpoints.end() && *insertion_point == offset) {
// The breakpoint is already set for this isolate.
return;
}
breakpoints.insert(insertion_point, offset);
DCHECK(std::is_sorted(all_breakpoints.begin(), all_breakpoints.end()));
// Find the insertion position within {all_breakpoints}.
insertion_point = std::lower_bound(all_breakpoints.begin(),
all_breakpoints.end(), offset);
bool breakpoint_exists =
insertion_point != all_breakpoints.end() && *insertion_point == offset;
// If the breakpoint was already set before, then we can just reuse the old
// code. Otherwise, recompile it. In any case, rewrite this isolate's stack
// to make sure that it uses up-to-date code containing the breakpoint.
WasmCode* new_code;
if (breakpoint_exists) {
new_code = native_module_->GetCode(func_index);
} else {
all_breakpoints.insert(insertion_point, offset);
int dead_breakpoint =
DeadBreakpoint(func_index, base::VectorOf(all_breakpoints), isolate);
new_code = RecompileLiftoffWithBreakpoints(
func_index, base::VectorOf(all_breakpoints), dead_breakpoint);
}
UpdateReturnAddresses(isolate, new_code, isolate_data.stepping_frame);
}
std::vector<int> FindAllBreakpoints(int func_index) {
DCHECK(!mutex_.TryLock()); // Mutex must be held externally.
std::set<int> breakpoints;
for (auto& data : per_isolate_data_) {
auto it = data.second.breakpoints_per_function.find(func_index);
if (it == data.second.breakpoints_per_function.end()) continue;
for (int offset : it->second) breakpoints.insert(offset);
}
return {breakpoints.begin(), breakpoints.end()};
}
void UpdateBreakpoints(int func_index, base::Vector<int> breakpoints,
Isolate* isolate, StackFrameId stepping_frame,
int dead_breakpoint) {
DCHECK(!mutex_.TryLock()); // Mutex is held externally.
WasmCode* new_code = RecompileLiftoffWithBreakpoints(
func_index, breakpoints, dead_breakpoint);
UpdateReturnAddresses(isolate, new_code, stepping_frame);
}
void FloodWithBreakpoints(WasmFrame* frame, ReturnLocation return_location) {
// 0 is an invalid offset used to indicate flooding.
constexpr int kFloodingBreakpoints[] = {0};
DCHECK(frame->wasm_code()->is_liftoff());
// Generate an additional source position for the current byte offset.
base::MutexGuard guard(&mutex_);
WasmCode* new_code = RecompileLiftoffWithBreakpoints(
frame->function_index(), base::ArrayVector(kFloodingBreakpoints), 0);
UpdateReturnAddress(frame, new_code, return_location);
per_isolate_data_[frame->isolate()].stepping_frame = frame->id();
}
bool PrepareStep(WasmFrame* frame) {
WasmCodeRefScope wasm_code_ref_scope;
wasm::WasmCode* code = frame->wasm_code();
if (!code->is_liftoff()) return false; // Cannot step in TurboFan code.
if (IsAtReturn(frame)) return false; // Will return after this step.
FloodWithBreakpoints(frame, kAfterBreakpoint);
return true;
}
void PrepareStepOutTo(WasmFrame* frame) {
WasmCodeRefScope wasm_code_ref_scope;
wasm::WasmCode* code = frame->wasm_code();
if (!code->is_liftoff()) return; // Cannot step out to TurboFan code.
FloodWithBreakpoints(frame, kAfterWasmCall);
}
void ClearStepping(WasmFrame* frame) {
WasmCodeRefScope wasm_code_ref_scope;
base::MutexGuard guard(&mutex_);
auto* code = frame->wasm_code();
if (code->for_debugging() != kForStepping) return;
int func_index = code->index();
std::vector<int> breakpoints = FindAllBreakpoints(func_index);
int dead_breakpoint = DeadBreakpoint(frame, base::VectorOf(breakpoints));
WasmCode* new_code = RecompileLiftoffWithBreakpoints(
func_index, base::VectorOf(breakpoints), dead_breakpoint);
UpdateReturnAddress(frame, new_code, kAfterBreakpoint);
}
void ClearStepping(Isolate* isolate) {
base::MutexGuard guard(&mutex_);
auto it = per_isolate_data_.find(isolate);
if (it != per_isolate_data_.end()) it->second.stepping_frame = NO_ID;
}
bool IsStepping(WasmFrame* frame) {
Isolate* isolate = frame->wasm_instance()->GetIsolate();
if (isolate->debug()->last_step_action() == StepInto) return true;
base::MutexGuard guard(&mutex_);
auto it = per_isolate_data_.find(isolate);
return it != per_isolate_data_.end() &&
it->second.stepping_frame == frame->id();
}
void RemoveBreakpoint(int func_index, int position, Isolate* isolate) {
// Put the code ref scope outside of the mutex, so we don't unnecessarily
// hold the mutex while freeing code.
WasmCodeRefScope wasm_code_ref_scope;
// Hold the mutex while modifying breakpoints, to ensure consistency when
// multiple isolates set/remove breakpoints at the same time.
base::MutexGuard guard(&mutex_);
const auto& function = native_module_->module()->functions[func_index];
int offset = position - function.code.offset();
auto& isolate_data = per_isolate_data_[isolate];
std::vector<int>& breakpoints =
isolate_data.breakpoints_per_function[func_index];
DCHECK_LT(0, offset);
auto insertion_point =
std::lower_bound(breakpoints.begin(), breakpoints.end(), offset);
if (insertion_point == breakpoints.end()) return;
if (*insertion_point != offset) return;
breakpoints.erase(insertion_point);
std::vector<int> remaining = FindAllBreakpoints(func_index);
// If the breakpoint is still set in another isolate, don't remove it.
DCHECK(std::is_sorted(remaining.begin(), remaining.end()));
if (std::binary_search(remaining.begin(), remaining.end(), offset)) return;
int dead_breakpoint =
DeadBreakpoint(func_index, base::VectorOf(remaining), isolate);
UpdateBreakpoints(func_index, base::VectorOf(remaining), isolate,
isolate_data.stepping_frame, dead_breakpoint);
}
void RemoveDebugSideTables(base::Vector<WasmCode* const> codes) {
base::MutexGuard guard(&debug_side_tables_mutex_);
for (auto* code : codes) {
debug_side_tables_.erase(code);
}
}
DebugSideTable* GetDebugSideTableIfExists(const WasmCode* code) const {
base::MutexGuard guard(&debug_side_tables_mutex_);
auto it = debug_side_tables_.find(code);
return it == debug_side_tables_.end() ? nullptr : it->second.get();
}
static bool HasRemovedBreakpoints(const std::vector<int>& removed,
const std::vector<int>& remaining) {
DCHECK(std::is_sorted(remaining.begin(), remaining.end()));
for (int offset : removed) {
// Return true if we removed a breakpoint which is not part of remaining.
if (!std::binary_search(remaining.begin(), remaining.end(), offset)) {
return true;
}
}
return false;
}
void RemoveIsolate(Isolate* isolate) {
// Put the code ref scope outside of the mutex, so we don't unnecessarily
// hold the mutex while freeing code.
WasmCodeRefScope wasm_code_ref_scope;
base::MutexGuard guard(&mutex_);
auto per_isolate_data_it = per_isolate_data_.find(isolate);
if (per_isolate_data_it == per_isolate_data_.end()) return;
std::unordered_map<int, std::vector<int>> removed_per_function =
std::move(per_isolate_data_it->second.breakpoints_per_function);
per_isolate_data_.erase(per_isolate_data_it);
for (auto& entry : removed_per_function) {
int func_index = entry.first;
std::vector<int>& removed = entry.second;
std::vector<int> remaining = FindAllBreakpoints(func_index);
if (HasRemovedBreakpoints(removed, remaining)) {
RecompileLiftoffWithBreakpoints(func_index, base::VectorOf(remaining),
0);
}
}
}
size_t EstimateCurrentMemoryConsumption() const {
UPDATE_WHEN_CLASS_CHANGES(DebugInfoImpl, 208);
UPDATE_WHEN_CLASS_CHANGES(CachedDebuggingCode, 40);
UPDATE_WHEN_CLASS_CHANGES(PerIsolateDebugData, 48);
size_t result = sizeof(DebugInfoImpl);
{
base::MutexGuard lock(&debug_side_tables_mutex_);
result += ContentSize(debug_side_tables_);
for (const auto& [code, table] : debug_side_tables_) {
result += table->EstimateCurrentMemoryConsumption();
}
}
{
base::MutexGuard lock(&mutex_);
result += ContentSize(cached_debugging_code_);
for (const CachedDebuggingCode& code : cached_debugging_code_) {
result += code.breakpoint_offsets.size() * sizeof(int);
}
result += ContentSize(per_isolate_data_);
for (const auto& [isolate, data] : per_isolate_data_) {
// Inlined handling of {PerIsolateDebugData}.
result += ContentSize(data.breakpoints_per_function);
for (const auto& [idx, breakpoints] : data.breakpoints_per_function) {
result += ContentSize(breakpoints);
}
}
}
if (v8_flags.trace_wasm_offheap_memory) {
PrintF("DebugInfo: %zu\n", result);
}
return result;
}
private:
struct FrameInspectionScope {
FrameInspectionScope(DebugInfoImpl* debug_info, Address pc,
Isolate* isolate)
: code(wasm::GetWasmCodeManager()->LookupCode(isolate, pc)),
pc_offset(static_cast<int>(pc - code->instruction_start())),
debug_side_table(code->is_inspectable()
? debug_info->GetDebugSideTable(code)
: nullptr),
debug_side_table_entry(debug_side_table
? debug_side_table->GetEntry(pc_offset)
: nullptr) {
DCHECK_IMPLIES(code->is_inspectable(), debug_side_table_entry != nullptr);
}
bool is_inspectable() const { return debug_side_table_entry; }
wasm::WasmCodeRefScope wasm_code_ref_scope;
wasm::WasmCode* code;
int pc_offset;
const DebugSideTable* debug_side_table;
const DebugSideTable::Entry* debug_side_table_entry;
};
const DebugSideTable* GetDebugSideTable(WasmCode* code) {
DCHECK(code->is_inspectable());
{
// Only hold the mutex temporarily. We can't hold it while generating the
// debug side table, because compilation takes the {NativeModule} lock.
base::MutexGuard guard(&debug_side_tables_mutex_);
auto it = debug_side_tables_.find(code);
if (it != debug_side_tables_.end()) return it->second.get();
}
// Otherwise create the debug side table now.
std::unique_ptr<DebugSideTable> debug_side_table =
GenerateLiftoffDebugSideTable(code);
DebugSideTable* ret = debug_side_table.get();
// Check cache again, maybe another thread concurrently generated a debug
// side table already.
{
base::MutexGuard guard(&debug_side_tables_mutex_);
auto& slot = debug_side_tables_[code];
if (slot != nullptr) return slot.get();
slot = std::move(debug_side_table);
}
// Print the code together with the debug table, if requested.
code->MaybePrint();
return ret;
}
// Get the value of a local (including parameters) or stack value. Stack
// values follow the locals in the same index space.
WasmValue GetValue(const DebugSideTable* debug_side_table,
const DebugSideTable::Entry* debug_side_table_entry,
int index, Address stack_frame_base,
Address debug_break_fp, Isolate* isolate) const {
const auto* value =
debug_side_table->FindValue(debug_side_table_entry, index);
if (value->is_constant()) {
DCHECK(value->type == kWasmI32 || value->type == kWasmI64);
return value->type == kWasmI32 ? WasmValue(value->i32_const)
: WasmValue(int64_t{value->i32_const});
}
if (value->is_register()) {
auto reg = LiftoffRegister::from_liftoff_code(value->reg_code);
auto gp_addr = [debug_break_fp](Register reg) {
return debug_break_fp +
WasmDebugBreakFrameConstants::GetPushedGpRegisterOffset(
reg.code());
};
if (reg.is_gp_pair()) {
DCHECK_EQ(kWasmI64, value->type);
uint32_t low_word = ReadUnalignedValue<uint32_t>(gp_addr(reg.low_gp()));
uint32_t high_word =
ReadUnalignedValue<uint32_t>(gp_addr(reg.high_gp()));
return WasmValue((uint64_t{high_word} << 32) | low_word);
}
if (reg.is_gp()) {
if (value->type == kWasmI32) {
return WasmValue(ReadUnalignedValue<uint32_t>(gp_addr(reg.gp())));
} else if (value->type == kWasmI64) {
return WasmValue(ReadUnalignedValue<uint64_t>(gp_addr(reg.gp())));
} else if (value->type.is_reference()) {
Handle<Object> obj(
Tagged<Object>(ReadUnalignedValue<Address>(gp_addr(reg.gp()))),
isolate);
return WasmValue(obj, value->type);
} else {
UNREACHABLE();
}
}
DCHECK(reg.is_fp() || reg.is_fp_pair());
// ifdef here to workaround unreachable code for is_fp_pair.
#ifdef V8_TARGET_ARCH_ARM
int code = reg.is_fp_pair() ? reg.low_fp().code() : reg.fp().code();
#else
int code = reg.fp().code();
#endif
Address spilled_addr =
debug_break_fp +
WasmDebugBreakFrameConstants::GetPushedFpRegisterOffset(code);
if (value->type == kWasmF32) {
return WasmValue(ReadUnalignedValue<float>(spilled_addr));
} else if (value->type == kWasmF64) {
return WasmValue(ReadUnalignedValue<double>(spilled_addr));
} else if (value->type == kWasmS128) {
return WasmValue(Simd128(ReadUnalignedValue<int16>(spilled_addr)));
} else {
// All other cases should have been handled above.
UNREACHABLE();
}
}
// Otherwise load the value from the stack.
Address stack_address = stack_frame_base - value->stack_offset;
switch (value->type.kind()) {
case kI32:
return WasmValue(ReadUnalignedValue<int32_t>(stack_address));
case kI64:
return WasmValue(ReadUnalignedValue<int64_t>(stack_address));
case kF32:
return WasmValue(ReadUnalignedValue<float>(stack_address));
case kF64:
return WasmValue(ReadUnalignedValue<double>(stack_address));
case kS128:
return WasmValue(Simd128(ReadUnalignedValue<int16>(stack_address)));
case kRef:
case kRefNull:
case kRtt: {
Handle<Object> obj(
Tagged<Object>(ReadUnalignedValue<Address>(stack_address)),
isolate);
return WasmValue(obj, value->type);
}
case kI8:
case kI16:
case kVoid:
case kBottom:
UNREACHABLE();
}
}
// After installing a Liftoff code object with a different set of breakpoints,
// update return addresses on the stack so that execution resumes in the new
// code. The frame layout itself should be independent of breakpoints.
void UpdateReturnAddresses(Isolate* isolate, WasmCode* new_code,
StackFrameId stepping_frame) {
// The first return location is after the breakpoint, others are after wasm
// calls.
ReturnLocation return_location = kAfterBreakpoint;
for (DebuggableStackFrameIterator it(isolate); !it.done();
it.Advance(), return_location = kAfterWasmCall) {
// We still need the flooded function for stepping.
if (it.frame()->id() == stepping_frame) continue;
if (!it.is_wasm()) continue;
WasmFrame* frame = WasmFrame::cast(it.frame());
if (frame->native_module() != new_code->native_module()) continue;
if (frame->function_index() != new_code->index()) continue;
if (!frame->wasm_code()->is_liftoff()) continue;
UpdateReturnAddress(frame, new_code, return_location);
}
}
void UpdateReturnAddress(WasmFrame* frame, WasmCode* new_code,
ReturnLocation return_location) {
DCHECK(new_code->is_liftoff());
DCHECK_EQ(frame->function_index(), new_code->index());
DCHECK_EQ(frame->native_module(), new_code->native_module());
DCHECK(frame->wasm_code()->is_liftoff());
Address new_pc = FindNewPC(frame, new_code, frame->generated_code_offset(),
return_location);
#ifdef DEBUG
int old_position = frame->position();
#endif
#if V8_TARGET_ARCH_X64
if (frame->wasm_code()->for_debugging()) {
base::Memory<Address>(frame->fp() - kOSRTargetOffset) = new_pc;
}
#else
PointerAuthentication::ReplacePC(frame->pc_address(), new_pc,
kSystemPointerSize);
#endif
// The frame position should still be the same after OSR.
DCHECK_EQ(old_position, frame->position());
}
bool IsAtReturn(WasmFrame* frame) {
DisallowGarbageCollection no_gc;
int position = frame->position();
NativeModule* native_module =
frame->wasm_instance()->module_object()->native_module();
uint8_t opcode = native_module->wire_bytes()[position];
if (opcode == kExprReturn) return true;
// Another implicit return is at the last kExprEnd in the function body.
int func_index = frame->function_index();
WireBytesRef code = native_module->module()->functions[func_index].code;
return static_cast<size_t>(position) == code.end_offset() - 1;
}
// Isolate-specific data, for debugging modules that are shared by multiple
// isolates.
struct PerIsolateDebugData {
// Keeps track of the currently set breakpoints (by offset within that
// function).
std::unordered_map<int, std::vector<int>> breakpoints_per_function;
// Store the frame ID when stepping, to avoid overwriting that frame when
// setting or removing a breakpoint.
StackFrameId stepping_frame = NO_ID;
};
NativeModule* const native_module_;
mutable base::Mutex debug_side_tables_mutex_;
// DebugSideTable per code object, lazily initialized.
std::unordered_map<const WasmCode*, std::unique_ptr<DebugSideTable>>
debug_side_tables_;
// {mutex_} protects all fields below.
mutable base::Mutex mutex_;
// Cache a fixed number of WasmCode objects that were generated for debugging.
// This is useful especially in stepping, because stepping code is cleared on
// every pause and re-installed on the next step.
// This is a LRU cache (most recently used entries first).
static constexpr size_t kMaxCachedDebuggingCode = 3;
struct CachedDebuggingCode {
int func_index;
base::OwnedVector<const int> breakpoint_offsets;
int dead_breakpoint;
WasmCode* code;
};
std::vector<CachedDebuggingCode> cached_debugging_code_;
// Isolate-specific data.
std::unordered_map<Isolate*, PerIsolateDebugData> per_isolate_data_;
};
DebugInfo::DebugInfo(NativeModule* native_module)
: impl_(std::make_unique<DebugInfoImpl>(native_module)) {}
DebugInfo::~DebugInfo() = default;
int DebugInfo::GetNumLocals(Address pc, Isolate* isolate) {
return impl_->GetNumLocals(pc, isolate);
}
WasmValue DebugInfo::GetLocalValue(int local, Address pc, Address fp,
Address debug_break_fp, Isolate* isolate) {
return impl_->GetLocalValue(local, pc, fp, debug_break_fp, isolate);
}
int DebugInfo::GetStackDepth(Address pc, Isolate* isolate) {
return impl_->GetStackDepth(pc, isolate);
}
WasmValue DebugInfo::GetStackValue(int index, Address pc, Address fp,
Address debug_break_fp, Isolate* isolate) {
return impl_->GetStackValue(index, pc, fp, debug_break_fp, isolate);
}
const wasm::WasmFunction& DebugInfo::GetFunctionAtAddress(Address pc,
Isolate* isolate) {
return impl_->GetFunctionAtAddress(pc, isolate);
}
void DebugInfo::SetBreakpoint(int func_index, int offset,
Isolate* current_isolate) {
impl_->SetBreakpoint(func_index, offset, current_isolate);
}
bool DebugInfo::PrepareStep(WasmFrame* frame) {
return impl_->PrepareStep(frame);
}
void DebugInfo::PrepareStepOutTo(WasmFrame* frame) {
impl_->PrepareStepOutTo(frame);
}
void DebugInfo::ClearStepping(Isolate* isolate) {
impl_->ClearStepping(isolate);
}
void DebugInfo::ClearStepping(WasmFrame* frame) { impl_->ClearStepping(frame); }
bool DebugInfo::IsStepping(WasmFrame* frame) {
return impl_->IsStepping(frame);
}
void DebugInfo::RemoveBreakpoint(int func_index, int offset,
Isolate* current_isolate) {
impl_->RemoveBreakpoint(func_index, offset, current_isolate);
}
void DebugInfo::RemoveDebugSideTables(base::Vector<WasmCode* const> code) {
impl_->RemoveDebugSideTables(code);
}
DebugSideTable* DebugInfo::GetDebugSideTableIfExists(
const WasmCode* code) const {
return impl_->GetDebugSideTableIfExists(code);
}
void DebugInfo::RemoveIsolate(Isolate* isolate) {
return impl_->RemoveIsolate(isolate);
}
size_t DebugInfo::EstimateCurrentMemoryConsumption() const {
return impl_->EstimateCurrentMemoryConsumption();
}
} // namespace wasm
namespace {
// Return the next breakable position at or after {offset_in_func} in function
// {func_index}, or 0 if there is none.
// Note that 0 is never a breakable position in wasm, since the first uint8_t
// contains the locals count for the function.
int FindNextBreakablePosition(wasm::NativeModule* native_module, int func_index,
int offset_in_func) {
Zone zone{wasm::GetWasmEngine()->allocator(), ZONE_NAME};
wasm::BodyLocalDecls locals;
const uint8_t* module_start = native_module->wire_bytes().begin();
const wasm::WasmFunction& func =
native_module->module()->functions[func_index];
wasm::BytecodeIterator iterator(module_start + func.code.offset(),
module_start + func.code.end_offset(),
&locals, &zone);
DCHECK_LT(0, locals.encoded_size);
if (offset_in_func < 0) return 0;
for (; iterator.has_next(); iterator.next()) {
if (iterator.pc_offset() < static_cast<uint32_t>(offset_in_func)) continue;
if (!wasm::WasmOpcodes::IsBreakable(iterator.current())) continue;
return static_cast<int>(iterator.pc_offset());
}
return 0;
}
void SetBreakOnEntryFlag(Tagged<Script> script, bool enabled) {
if (script->break_on_entry() == enabled) return;
script->set_break_on_entry(enabled);
// Update the "break_on_entry" flag on all live instances.
i::Tagged<i::WeakArrayList> weak_instance_list =
script->wasm_weak_instance_list();
i::Isolate* isolate = script->GetIsolate();
for (int i = 0; i < weak_instance_list->length(); ++i) {
if (weak_instance_list->Get(i).IsCleared()) continue;
i::Tagged<i::WasmInstanceObject> instance =
i::WasmInstanceObject::cast(weak_instance_list->Get(i).GetHeapObject());
instance->trusted_data(isolate)->set_break_on_entry(enabled);
}
}
} // namespace
// static
bool WasmScript::SetBreakPoint(Handle<Script> script, int* position,
Handle<BreakPoint> break_point) {
DCHECK_NE(kOnEntryBreakpointPosition, *position);
// Find the function for this breakpoint.
const wasm::WasmModule* module = script->wasm_native_module()->module();
int func_index = GetContainingWasmFunction(module, *position);
if (func_index < 0) return false;
const wasm::WasmFunction& func = module->functions[func_index];
int offset_in_func = *position - func.code.offset();
int breakable_offset = FindNextBreakablePosition(script->wasm_native_module(),
func_index, offset_in_func);
if (breakable_offset == 0) return false;
*position = func.code.offset() + breakable_offset;
return WasmScript::SetBreakPointForFunction(script, func_index,
breakable_offset, break_point);
}
// static
void WasmScript::SetInstrumentationBreakpoint(Handle<Script> script,
Handle<BreakPoint> break_point) {
// Special handling for on-entry breakpoints.
AddBreakpointToInfo(script, kOnEntryBreakpointPosition, break_point);
// Update the "break_on_entry" flag on all live instances.
SetBreakOnEntryFlag(*script, true);
}
// static
bool WasmScript::SetBreakPointOnFirstBreakableForFunction(
Handle<Script> script, int func_index, Handle<BreakPoint> break_point) {
if (func_index < 0) return false;
int offset_in_func = 0;
int breakable_offset = FindNextBreakablePosition(script->wasm_native_module(),
func_index, offset_in_func);
if (breakable_offset == 0) return false;
return WasmScript::SetBreakPointForFunction(script, func_index,
breakable_offset, break_point);
}
// static
bool WasmScript::SetBreakPointForFunction(Handle<Script> script, int func_index,
int offset,
Handle<BreakPoint> break_point) {
Isolate* isolate = script->GetIsolate();
DCHECK_LE(0, func_index);
DCHECK_NE(0, offset);
// Find the function for this breakpoint.
wasm::NativeModule* native_module = script->wasm_native_module();
const wasm::WasmModule* module = native_module->module();
const wasm::WasmFunction& func = module->functions[func_index];
// Insert new break point into {wasm_breakpoint_infos} of the script.
AddBreakpointToInfo(script, func.code.offset() + offset, break_point);
native_module->GetDebugInfo()->SetBreakpoint(func_index, offset, isolate);
return true;
}
namespace {
int GetBreakpointPos(Isolate* isolate,
Tagged<Object> break_point_info_or_undef) {
if (IsUndefined(break_point_info_or_undef, isolate)) return kMaxInt;
return BreakPointInfo::cast(break_point_info_or_undef)->source_position();
}
int FindBreakpointInfoInsertPos(Isolate* isolate,
Handle<FixedArray> breakpoint_infos,
int position) {
// Find insert location via binary search, taking care of undefined values on
// the right. {position} is either {kOnEntryBreakpointPosition} (which is -1),
// or positive.
DCHECK(position == WasmScript::kOnEntryBreakpointPosition || position > 0);
int left = 0; // inclusive
int right = breakpoint_infos->length(); // exclusive
while (right - left > 1) {
int mid = left + (right - left) / 2;
Tagged<Object> mid_obj = breakpoint_infos->get(mid);
if (GetBreakpointPos(isolate, mid_obj) <= position) {
left = mid;
} else {
right = mid;
}
}
int left_pos = GetBreakpointPos(isolate, breakpoint_infos->get(left));
return left_pos < position ? left + 1 : left;
}
} // namespace
// static
bool WasmScript::ClearBreakPoint(Handle<Script> script, int position,
Handle<BreakPoint> break_point) {
if (!script->has_wasm_breakpoint_infos()) return false;
Isolate* isolate = script->GetIsolate();
Handle<FixedArray> breakpoint_infos(script->wasm_breakpoint_infos(), isolate);
int pos = FindBreakpointInfoInsertPos(isolate, breakpoint_infos, position);
// Does a BreakPointInfo object already exist for this position?
if (pos == breakpoint_infos->length()) return false;
Handle<BreakPointInfo> info(BreakPointInfo::cast(breakpoint_infos->get(pos)),
isolate);
BreakPointInfo::ClearBreakPoint(isolate, info, break_point);
// Check if there are no more breakpoints at this location.
if (info->GetBreakPointCount(isolate) == 0) {
// Update array by moving breakpoints up one position.
for (int i = pos; i < breakpoint_infos->length() - 1; i++) {
Tagged<Object> entry = breakpoint_infos->get(i + 1);
breakpoint_infos->set(i, entry);
if (IsUndefined(entry, isolate)) break;
}
// Make sure last array element is empty as a result.
breakpoint_infos->set(breakpoint_infos->length() - 1,
ReadOnlyRoots{isolate}.undefined_value(),
SKIP_WRITE_BARRIER);
}
if (break_point->id() == v8::internal::Debug::kInstrumentationId) {
// Special handling for instrumentation breakpoints.
SetBreakOnEntryFlag(*script, false);
} else {
// Remove the breakpoint from DebugInfo and recompile.
wasm::NativeModule* native_module = script->wasm_native_module();
const wasm::WasmModule* module = native_module->module();
int func_index = GetContainingWasmFunction(module, position);
native_module->GetDebugInfo()->RemoveBreakpoint(func_index, position,
isolate);
}
return true;
}
// static
bool WasmScript::ClearBreakPointById(Handle<Script> script, int breakpoint_id) {
if (!script->has_wasm_breakpoint_infos()) {
return false;
}
Isolate* isolate = script->GetIsolate();
Handle<FixedArray> breakpoint_infos(script->wasm_breakpoint_infos(), isolate);
// If the array exists, it should not be empty.
DCHECK_LT(0, breakpoint_infos->length());
for (int i = 0, e = breakpoint_infos->length(); i < e; ++i) {
Handle<Object> obj(breakpoint_infos->get(i), isolate);
if (IsUndefined(*obj, isolate)) {
continue;
}
Handle<BreakPointInfo> breakpoint_info = Handle<BreakPointInfo>::cast(obj);
Handle<BreakPoint> breakpoint;
if (BreakPointInfo::GetBreakPointById(isolate, breakpoint_info,
breakpoint_id)
.ToHandle(&breakpoint)) {
DCHECK(breakpoint->id() == breakpoint_id);
return WasmScript::ClearBreakPoint(
script, breakpoint_info->source_position(), breakpoint);
}
}
return false;
}
// static
void WasmScript::ClearAllBreakpoints(Tagged<Script> script) {
script->set_wasm_breakpoint_infos(
ReadOnlyRoots(script->GetIsolate()).empty_fixed_array());
SetBreakOnEntryFlag(script, false);
}
// static
void WasmScript::AddBreakpointToInfo(Handle<Script> script, int position,
Handle<BreakPoint> break_point) {
Isolate* isolate = script->GetIsolate();
Handle<FixedArray> breakpoint_infos;
if (script->has_wasm_breakpoint_infos()) {
breakpoint_infos = handle(script->wasm_breakpoint_infos(), isolate);
} else {
breakpoint_infos =
isolate->factory()->NewFixedArray(4, AllocationType::kOld);
script->set_wasm_breakpoint_infos(*breakpoint_infos);
}
int insert_pos =
FindBreakpointInfoInsertPos(isolate, breakpoint_infos, position);
// If a BreakPointInfo object already exists for this position, add the new
// breakpoint object and return.
if (insert_pos < breakpoint_infos->length() &&
GetBreakpointPos(isolate, breakpoint_infos->get(insert_pos)) ==
position) {
Handle<BreakPointInfo> old_info(
BreakPointInfo::cast(breakpoint_infos->get(insert_pos)), isolate);
BreakPointInfo::SetBreakPoint(isolate, old_info, break_point);
return;
}
// Enlarge break positions array if necessary.
bool need_realloc = !IsUndefined(
breakpoint_infos->get(breakpoint_infos->length() - 1), isolate);
Handle<FixedArray> new_breakpoint_infos = breakpoint_infos;
if (need_realloc) {
new_breakpoint_infos = isolate->factory()->NewFixedArray(
2 * breakpoint_infos->length(), AllocationType::kOld);
script->set_wasm_breakpoint_infos(*new_breakpoint_infos);
// Copy over the entries [0, insert_pos).
for (int i = 0; i < insert_pos; ++i)
new_breakpoint_infos->set(i, breakpoint_infos->get(i));
}
// Move elements [insert_pos, ...] up by one.
for (int i = breakpoint_infos->length() - 1; i >= insert_pos; --i) {
Tagged<Object> entry = breakpoint_infos->get(i);
if (IsUndefined(entry, isolate)) continue;
new_breakpoint_infos->set(i + 1, entry);
}
// Generate new BreakpointInfo.
Handle<BreakPointInfo> breakpoint_info =
isolate->factory()->NewBreakPointInfo(position);
BreakPointInfo::SetBreakPoint(isolate, breakpoint_info, break_point);
// Now insert new position at insert_pos.
new_breakpoint_infos->set(insert_pos, *breakpoint_info);
}
// static
bool WasmScript::GetPossibleBreakpoints(
wasm::NativeModule* native_module, const v8::debug::Location& start,
const v8::debug::Location& end,
std::vector<v8::debug::BreakLocation>* locations) {
DisallowGarbageCollection no_gc;
const wasm::WasmModule* module = native_module->module();
const std::vector<wasm::WasmFunction>& functions = module->functions;
if (start.GetLineNumber() != 0 || start.GetColumnNumber() < 0 ||
(!end.IsEmpty() &&
(end.GetLineNumber() != 0 || end.GetColumnNumber() < 0 ||
end.GetColumnNumber() < start.GetColumnNumber())))
return false;
// start_func_index, start_offset and end_func_index is inclusive.
// end_offset is exclusive.
// start_offset and end_offset are module-relative byte offsets.
// We set strict to false because offsets may be between functions.
int start_func_index =
GetNearestWasmFunction(module, start.GetColumnNumber());
if (start_func_index < 0) return false;
uint32_t start_offset = start.GetColumnNumber();
int end_func_index;
uint32_t end_offset;
if (end.IsEmpty()) {
// Default: everything till the end of the Script.
end_func_index = static_cast<uint32_t>(functions.size() - 1);
end_offset = functions[end_func_index].code.end_offset();
} else {
// If end is specified: Use it and check for valid input.
end_offset = end.GetColumnNumber();
end_func_index = GetNearestWasmFunction(module, end_offset);
DCHECK_GE(end_func_index, start_func_index);
}
if (start_func_index == end_func_index &&
start_offset > functions[end_func_index].code.end_offset())
return false;
Zone zone{wasm::GetWasmEngine()->allocator(), ZONE_NAME};
const uint8_t* module_start = native_module->wire_bytes().begin();
for (int func_idx = start_func_index; func_idx <= end_func_index;
++func_idx) {
const wasm::WasmFunction& func = functions[func_idx];
if (func.code.length() == 0) continue;
wasm::BodyLocalDecls locals;
wasm::BytecodeIterator iterator(module_start + func.code.offset(),
module_start + func.code.end_offset(),
&locals, &zone);
DCHECK_LT(0u, locals.encoded_size);
for (; iterator.has_next(); iterator.next()) {
uint32_t total_offset = func.code.offset() + iterator.pc_offset();
if (total_offset >= end_offset) {
DCHECK_EQ(end_func_index, func_idx);
break;
}
if (total_offset < start_offset) continue;
if (!wasm::WasmOpcodes::IsBreakable(iterator.current())) continue;
locations->emplace_back(0, total_offset, debug::kCommonBreakLocation);
}
}
return true;
}
namespace {
bool CheckBreakPoint(Isolate* isolate, Handle<BreakPoint> break_point,
StackFrameId frame_id) {
if (break_point->condition()->length() == 0) return true;
HandleScope scope(isolate);
Handle<String> condition(break_point->condition(), isolate);
Handle<Object> result;
// The Wasm engine doesn't perform any sort of inlining.
const int inlined_jsframe_index = 0;
const bool throw_on_side_effect = false;
if (!DebugEvaluate::Local(isolate, frame_id, inlined_jsframe_index, condition,
throw_on_side_effect)
.ToHandle(&result)) {
isolate->clear_exception();
return false;
}
return Object::BooleanValue(*result, isolate);
}
} // namespace
// static
MaybeHandle<FixedArray> WasmScript::CheckBreakPoints(Isolate* isolate,
Handle<Script> script,
int position,
StackFrameId frame_id) {
if (!script->has_wasm_breakpoint_infos()) return {};
Handle<FixedArray> breakpoint_infos(script->wasm_breakpoint_infos(), isolate);
int insert_pos =
FindBreakpointInfoInsertPos(isolate, breakpoint_infos, position);
if (insert_pos >= breakpoint_infos->length()) return {};
Handle<Object> maybe_breakpoint_info(breakpoint_infos->get(insert_pos),
isolate);
if (IsUndefined(*maybe_breakpoint_info, isolate)) return {};
Handle<BreakPointInfo> breakpoint_info =
Handle<BreakPointInfo>::cast(maybe_breakpoint_info);
if (breakpoint_info->source_position() != position) return {};
Handle<Object> break_points(breakpoint_info->break_points(), isolate);
if (!IsFixedArray(*break_points)) {
if (!CheckBreakPoint(isolate, Handle<BreakPoint>::cast(break_points),
frame_id)) {
return {};
}
Handle<FixedArray> break_points_hit = isolate->factory()->NewFixedArray(1);
break_points_hit->set(0, *break_points);
return break_points_hit;
}
Handle<FixedArray> array = Handle<FixedArray>::cast(break_points);
Handle<FixedArray> break_points_hit =
isolate->factory()->NewFixedArray(array->length());
int break_points_hit_count = 0;
for (int i = 0; i < array->length(); ++i) {
Handle<BreakPoint> break_point(BreakPoint::cast(array->get(i)), isolate);
if (CheckBreakPoint(isolate, break_point, frame_id)) {
break_points_hit->set(break_points_hit_count++, *break_point);
}
}
if (break_points_hit_count == 0) return {};
break_points_hit->RightTrim(isolate, break_points_hit_count);
return break_points_hit;
}
} // namespace internal
} // namespace v8