1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
|
// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROME_RENDERER_V8_UNWINDER_H_
#define CHROME_RENDERER_V8_UNWINDER_H_
#include <memory>
#include <set>
#include "base/check_op.h"
#include "base/memory/raw_ptr.h"
#include "base/profiler/unwinder.h"
#include "v8/include/v8-unwinder.h"
namespace v8 {
class Isolate;
} // namespace v8
// Implements stack frame unwinding for V8 generated code frames, for use with
// the StackSamplingProfiler.
class V8Unwinder : public base::Unwinder {
public:
explicit V8Unwinder(v8::Isolate* isolate);
~V8Unwinder() override;
V8Unwinder(const V8Unwinder&) = delete;
V8Unwinder& operator=(const V8Unwinder&) = delete;
// Unwinder:
void InitializeModules() override;
std::unique_ptr<base::UnwinderStateCapture> CreateUnwinderStateCapture()
override;
void OnStackCapture(base::UnwinderStateCapture* capture_state) override;
void UpdateModules(base::UnwinderStateCapture* capture_state) override;
bool CanUnwindFrom(const base::Frame& current_frame) const override;
base::UnwindResult TryUnwind(base::UnwinderStateCapture* capture_state,
base::RegisterContext* thread_context,
uintptr_t stack_top,
std::vector<base::Frame>* stack) override;
// Build ids generated by the unwinder. Exposed for test use.
static const char kV8EmbeddedCodeRangeBuildId[];
static const char kV8CodeRangeBuildId[];
protected:
// Invokes CopyCodePages on the Isolate. Virtual to provide a seam for testing
// of module processing behavior.
virtual size_t CopyCodePages(size_t capacity, v8::MemoryRange* code_pages);
private:
// Custom container for storing V8 code memory ranges. We use this type rather
// than std::vector to guarantee that no heap allocation occurs during the
// operations used in OnStackCapture().
class MemoryRanges : public base::UnwinderStateCapture {
public:
explicit MemoryRanges(size_t size);
~MemoryRanges() override;
// Functions that must not heap allocate:
// Returns a pointer to the start of the internal buffer.
v8::MemoryRange* buffer() { return ranges_.get(); }
const v8::MemoryRange* buffer() const { return ranges_.get(); }
size_t size() const { return size_; }
// Shrinks the size if `size_` is larger than `size`.
void ShrinkSize(size_t size);
private:
size_t size_;
std::unique_ptr<v8::MemoryRange[]> ranges_;
};
// Compares modules by their extents in memory.
struct ModuleCompare {
bool operator()(const base::ModuleCache::Module* a,
const base::ModuleCache::Module* b) const;
};
const raw_ptr<v8::Isolate> isolate_;
const v8::JSEntryStubs js_entry_stubs_;
const v8::MemoryRange embedded_code_range_;
// The number of code ranges required to represent all of ranges supplied by
// V8 on the last call to CopyCodePages().
size_t required_code_ranges_capacity_ = 0;
// Records the currently active V8 modules, ordered by their extents in
// memory.
std::set<raw_ptr<const base::ModuleCache::Module, SetExperimental>,
ModuleCompare>
modules_;
};
#endif // CHROME_RENDERER_V8_UNWINDER_H_
|
