This patch updates internal data structures used by V8 to support
multiple indirect function tables (WebAssembly/design#682). But, since
this feature is post-MVP, the functionality is not directly exposed and
parsing/generation of WebAssembly is left unchanged. Nevertheless, it
is being used in an experiment to implement fine-grained control flow
integrity based on C/C++ types.
BUG=
Review-Url: https://codereview.chromium.org/2174123002
Cr-Commit-Position: refs/heads/master@{#38110}
In the current implementation of wasm an unrepresentable input of the
float32-to-int32 conversion is detected by first truncating the input, then
converting the truncated input to int32 and back to float32, and then checking
whether the result is the same as the truncated input.
This input check does not work on arm and arm64 for an input of (INT32_MAX + 1)
because on these platforms the float32-to-int32 conversion results in INT32_MAX
if the input is greater than INT32_MAX. When INT32_MAX is converted back to
float32, then the result is (INT32_MAX + 1) again because INT32_MAX cannot be
represented precisely as float32, and rounding-to-nearest results in (INT32_MAX
+ 1). Since (INT32_MAX + 1) equals the truncated input value, the input appears
to be representable.
With the changes in this CL, the result of the float32-to-int32 conversion is
incremented by 1 if the original result was INT32_MAX. Thereby the detection of
unrepresenable inputs in wasm works. Note that since INT32_MAX cannot be
represented precisely in float32, it can also never be a valid result of the
float32-to-int32 conversion.
@v8-mips-ports, can you do a similar implementation for mips?
R=titzer@chromium.org, Rodolph.Perfetta@arm.com
Review-Url: https://codereview.chromium.org/2105313002
Cr-Commit-Position: refs/heads/master@{#37448}
Reland of https://codereview.chromium.org/2034093002 (reverted by
https://codereview.chromium.org/2080153002).
Original commit message:
Implement WASM support on big-endian platforms. WASM has
an implicit requirement that it is running on little-endian
machine. We achieve WASM support on BE by keeping data
in memory in little-endian order, and changing data
endianness before storing to memory and after loading from
memory.
BUG=
Review-Url: https://codereview.chromium.org/2083523002
Cr-Commit-Position: refs/heads/master@{#37373}
Cleaning up the code to replace all instances of "i++" in for loops with the more efficient "++i".
The latter foregoes an extra intermediate variable.
BUG=v8:5044
Review-Url: https://codereview.chromium.org/2094573002
Cr-Commit-Position: refs/heads/master@{#37230}
Port 481502dad9
Float32SubMinusZero and Float64SubMinusZero tests are failing because MIPS does not preserve NaN payload according to Wasm spec. Implemented macro-assembler methods that check for NaN operands, and return the qNaN value with preserved payload and sign bits.
TEST=cctest/test-run-wasm/Run_WasmFloat32SubMinusZero, cctest/test-run-wasm/Run_WasmFloat64SubMinusZero
BUG=
patch from issue 2019693002 at patchset 140001 (http://crrev.com/2019693002#ps140001)
R=ahaas@chromium.org
Review-Url: https://codereview.chromium.org/2066483008
Cr-Commit-Position: refs/heads/master@{#37105}
Reason for revert:
[Sheriff] Speculative revert for crashes on chrubuntu chromebooks:
https://build.chromium.org/p/client.v8.ports/builders/V8%20Arm/builds/320
Original issue's description:
> Implement WASM big-endian support.
>
> Implement WASM support on big-endian platforms. WASM has
> an implicit requirement that it is running on little-endian
> machine. We achieve WASM support on BE by keeping data
> in memory in little-endian order, and changing data
> endianness before storing to memory and after loading from
> memory.
>
> BUG=
>
> Committed: https://crrev.com/d3f3f6c8186b2a53f0c539f7bba0c3708c4d83f9
> Cr-Commit-Position: refs/heads/master@{#37065}
TBR=titzer@chromium.org,akos.palfi@imgtec.com,balazs.kilvady@imgtec.com,jyan@ca.ibm.com,ivica.bogosavljevic@imgtec.com
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=
Review-Url: https://codereview.chromium.org/2080153002
Cr-Commit-Position: refs/heads/master@{#37091}
Implement WASM support on big-endian platforms. WASM has
an implicit requirement that it is running on little-endian
machine. We achieve WASM support on BE by keeping data
in memory in little-endian order, and changing data
endianness before storing to memory and after loading from
memory.
BUG=
Review-Url: https://codereview.chromium.org/2034093002
Cr-Commit-Position: refs/heads/master@{#37065}
This interpreter directly decodes and executes WASM binary code for
the purpose of supporting low-level debugging. It is not currently
integrated into the main WASM implementation.
R=ahaas@chromium.org,clemensh@chromium.org,rossberg@chromium.org,binji@chromium.org
BUG=
Review-Url: https://codereview.chromium.org/1972153002
Cr-Commit-Position: refs/heads/master@{#36497}
