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  1. 31 Mar, 2020 1 commit
  3. 21 Oct, 2019 1 commit
    • Seth Brenith's avatar
      Fix JSEntry unwinding data on Windows ARM64 · cdf8925e
      Seth Brenith authored 
      The current unwinding data for JSEntry correctly restores the frame
pointer and program counter from the caller frame, which might or might
not be sufficient to continue unwinding, depending on the contents of
that caller frame. Currently, the cctest StackUnwindingWin64 is broken
(at least with my build config) because the caller frame also needs the
stack pointer, which is not restored correctly.

In particular, I see this xdata for v8::internal::GeneratedCode<...>,
which is the function that calls Builtins_JSEntry:

10400015 : 2 code words, 1 epilog, function length=15
01000012 : epilog starts at 12 and its unwind handler starts at 4
e405c8d2 : save_reg x=b z=8
           alloc_s x=5
           end
e405c8d2 : same thing but for the epilog

The prolog that corresponds to the unwind codes above is:

sub sp, sp, #50
str lr, [sp, #0x40]

Note that it does not set fp, so unwinding requires an accurate sp.

This change emits slightly more complicated unwinding data for JSEntry
so that the frame pointer, stack pointer, and program counter can all be
restored.

Change-Id: I0c7f3eba97ef64408f46631b487c4b0ceb06fa9b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1848860
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarMichael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64435}
      cdf8925e
  5. 31 Jul, 2019 1 commit
    • Tom Tan's avatar
      Unwind V8 frames correctly on Windows ARM64 · 3f1f001a
      Tom Tan authored 
      On Windows ARM64, OS stack walking does not work because the V8 ARM64 backend
doesn't emit unwinding info and also because it doesn't emit ABI compliant
stack frames. This was fixed for Windows X64 (https://crrev.com/c/1469329) and
documented below:

https://docs.google.com/document/d/1-wf50jFlii0c_Pr52lm2ZU-49m220nhYMrHDi3vXnh0

This problem can be fixed similarly for Windows ARM64 by observing that V8
frames usually all have the same prolog which maintains a chain via frame
pointer (fp or x29 register).

stp fp, lr, [sp, ...]

One exception is JSEntry which stops fp pointer chain and needs to be handled
specially.

So it is possible to define XDATA with UNWIND_CODE which specify how Windows
should walk through V8 dynamic frames. The same as X64, since V8 Code objects
are all allocated in the same code-range for an Isolate, it is possible to
register at most 2 XDATA and a group of PDATA entries to cover stack walking
for all the code generated inside that code-range. This is more than 1
PDATA/XDATA because according to the Windows ARM64 exeption handling document,
1 PDATA can cover less than 1MB code range (see below doc).

https://docs.microsoft.com/en-us/cpp/build/arm64-exception-handling

This PR implements stackwalk for Windows ARM64 to be on par with X64, including
embedded builtins, jitted code and wasm jitted code, but not including register
handler for handling exception only, because there is no backward compatibility
to maintain for Windows ARM64 which was released since 1709 windows build.

Bug: chromium:893460
Change-Id: Ic74cbdad8af5cf342185030a4c53796f12ea5429
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1701133Reviewed-by: 's avatarMichael Starzinger <mstarzinger@chromium.org>
Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63002}
      3f1f001a
  7. 28 May, 2019 3 commits
  9. 27 May, 2019 2 commits
  11. 23 May, 2019 1 commit
  13. 22 May, 2019 1 commit
  15. 21 May, 2019 1 commit
  17. 20 May, 2019 1 commit
  19. 17 May, 2019 3 commits
  21. 10 Apr, 2019 1 commit
  23. 03 Apr, 2019 1 commit
    • Paolo Severini's avatar
      Reland "V8 x64 backend doesn't emit ABI compliant stack frames" · 969cb0c7
      Paolo Severini authored 
      This is a reland of 3cda21de

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/+/1534618Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarUlan Degenbaev <ulan@chromium.org>
Reviewed-by: 's avatarMichael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Paolo Severini <paolosev@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#60581}
      969cb0c7
  25. 20 Mar, 2019 1 commit
    • Leszek Swirski's avatar
      Revert "V8 x64 backend doesn't emit ABI compliant stack frames" · 9f6ddb48
      Leszek Swirski authored 
      This reverts commit 3cda21de.

Reason for revert: Breaks the roll on Windows (see https://cr-buildbucket.appspot.com/build/8918477701097622400)

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}

TBR=bbudge@chromium.org,ulan@chromium.org,mvstanton@chromium.org,mstarzinger@chromium.org,gdeepti@chromium.org,jgruber@chromium.org,paolosev@microsoft.com

Change-Id: If8470da94c58df8c800cbe8887f9f86236e43353
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:3598
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1532321Reviewed-by: 's avatarLeszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60372}
      9f6ddb48
  27. 19 Mar, 2019 1 commit
    • Paolo Severini's avatar
      V8 x64 backend doesn't emit ABI compliant stack frames · 3cda21de
      Paolo Severini authored 
      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/+/1469329Reviewed-by: 's avatarMichael Starzinger <mstarzinger@chromium.org>
Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarUlan Degenbaev <ulan@chromium.org>
Commit-Queue: Paolo Severini <paolosev@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#60330}
      3cda21de