v8/src/unwinding-info-win64.h
Paolo Severini 969cb0c7a5 Reland "V8 x64 backend doesn't emit ABI compliant stack frames"
This is a reland of 3cda21de77

Original change's description:
> V8 x64 backend doesn't emit ABI compliant stack frames
> 
> On 64 bit Windows, the OS stack walking does not work because the V8 x64
> backend doesn't emit unwinding info and also because it doesn't emit ABI
> compliant stack frames. See
> https://docs.google.com/document/d/1-wf50jFlii0c_Pr52lm2ZU-49m220nhYMrHDi3vXnh0/edit
> for more details.
> 
> This problem can be fixed by observing that V8 frames usually all have the same
> prolog and epilog:
> 
> push rbp,
> mov rbp, rsp
> ...
> pop rbp
> ret N
> 
> and that it is possible to define XDATA (UNWIND_CODEs) that specify how Windows
> should walk through V8 frames. Furthermore, since V8 Code objects are all
> allocated in the same code-range for an Isolate, it is possible to register a
> single PDATA/XDATA entry to cover stack walking for all the code generated
> inside that code-range.
> 
> This PR contains changes required to enable stack walking on Win64:
> 
> EmbeddedFileWriter now adds assembler directives to the builtins
> snapshot source file (embedded.cc) to emit additional entries in the .pdata and
> in the .xdata section of the V8 executable. This takes care of stack walking
> for embedded builtins. (The case of non-embedded builtins is not supported).
> The x64 Assembler has been modified to collect the information required to emit
> this unwind info for builtins.
> 
> Stack walking for jitted code is handled is Isolate.cpp, by registering
> dynamically PDATA/XDATA for the whole code-range address space every time a new
> Isolate is initialized, and by unregistering them when the Isolate is
> destroyed.
> 
> Stack walking for WASM jitted code is handled is the same way in
> wasm::NativeModule (wasm/wasm-code-manager.cpp).
> 
> It is important to note that Crashpad and Breakpad are already registering
> PDATA/XDATA to manage and report unhandled exceptions (but not for embedded
> builtins). Since it is not possible to register multiple PDATA entries for the
> same address range, a new function is added to the V8 API:
> SetUnhandledExceptionCallback() can be used by an embedder to register its own
> unhandled exception handler for exceptions that arise in v8-generated code.
> V8 embedders should be modified accordingly (code for this is in a separate PR
> in the Chromium repository:
> https://chromium-review.googlesource.com/c/chromium/src/+/1474703).
> 
> All these changes are experimental, behind:
> 
> the 'v8_win64_unwinding_info' build flag, and
> the '--win64-unwinding-info' runtime flag.
> 
> Bug: v8:3598
> Change-Id: Iea455ab6d0e2bf1c556aa1cf870841d44ab6e4b1
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1469329
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Paolo Severini <paolosev@microsoft.com>
> Cr-Commit-Position: refs/heads/master@{#60330}

Bug: v8:3598
Change-Id: If988baf7d3e4af165b919d6e54c1ad985f8e25e3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1534618
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Paolo Severini <paolosev@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#60581}
2019-04-03 02:00:43 +00:00

102 lines
3.0 KiB
C++

// Copyright 2019 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.
#ifndef V8_UNWINDING_INFO_WIN64_H_
#define V8_UNWINDING_INFO_WIN64_H_
#include "include/v8config.h"
#if defined(V8_OS_WIN_X64)
#include "include/v8.h"
#include "src/base/win32-headers.h"
#include "src/globals.h"
namespace v8 {
namespace internal {
namespace win64_unwindinfo {
#define CRASH_HANDLER_FUNCTION_NAME CrashForExceptionInNonABICompliantCodeRange
#define CRASH_HANDLER_FUNCTION_NAME_STRING \
"CrashForExceptionInNonABICompliantCodeRange"
static const int kPushRbpInstructionLength = 1;
static const int kMovRbpRspInstructionLength = 3;
static const int kRbpPrefixCodes = 2;
static const int kRbpPrefixLength =
kPushRbpInstructionLength + kMovRbpRspInstructionLength;
/**
* Returns true if V8 is configured to emit unwinding data for embedded in the
* pdata/xdata sections of the executable. Currently, this happens when V8 is
* built with "v8_win64_unwinding_info = true".
*/
bool CanEmitUnwindInfoForBuiltins();
/**
* Returns true if V8 if we can register unwinding data for the whole code range
* of an isolate or WASM module. The first page of the code range is reserved
* and writable, to be used to store unwind data, as documented in:
* https://docs.microsoft.com/en-us/cpp/build/exception-handling-x64.
* In jitless mode V8 does not allocate any executable memory itself so the only
* non-abi-compliant code range is in the embedded blob.
*/
bool CanRegisterUnwindInfoForNonABICompliantCodeRange();
/**
* Registers a custom exception handler for exceptions in V8-generated code.
*/
void SetUnhandledExceptionCallback(
v8::UnhandledExceptionCallback unhandled_exception_callback);
/**
* Returns a vector of bytes that contains the Win64 unwind data used for all
* V8 builtin functions.
*/
std::vector<uint8_t> GetUnwindInfoForBuiltinFunctions();
void RegisterNonABICompliantCodeRange(void* start, size_t size_in_bytes);
void UnregisterNonABICompliantCodeRange(void* start);
class BuiltinUnwindInfo {
public:
BuiltinUnwindInfo() : is_leaf_function_(true) {}
explicit BuiltinUnwindInfo(const std::vector<int>& fp_offsets)
: is_leaf_function_(false), fp_offsets_(fp_offsets) {}
bool is_leaf_function() const { return is_leaf_function_; }
const std::vector<int>& fp_offsets() const { return fp_offsets_; }
private:
bool is_leaf_function_;
std::vector<int> fp_offsets_;
};
class XdataEncoder {
public:
explicit XdataEncoder(const Assembler& assembler)
: assembler_(assembler), current_push_rbp_offset_(-1) {}
void onPushRbp();
void onMovRbpRsp();
BuiltinUnwindInfo unwinding_info() const {
return BuiltinUnwindInfo(fp_offsets_);
}
private:
const Assembler& assembler_;
std::vector<int> fp_offsets_;
int current_push_rbp_offset_;
};
} // namespace win64_unwindinfo
} // namespace internal
} // namespace v8
#endif // defined(V8_OS_WIN_X64)
#endif // V8_UNWINDING_INFO_WIN64_H_