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[wasm] Do not try to relocate off-heap trampolines

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Off-heap trampolines (short trampolines that jump to .text-embedded
builtin instruction streams) should contain exactly one OFF_HEAP_TARGET
reloc entry.

When AddAnonymousCode is called on such a trampoline, it copies the
(off-heap) *instruction stream* and thus should never perform any
relocations using the *trampoline's* RelocInfo.

Bug: v8:6666
Change-Id: I09a11344fb7e62d759c4c943712e7d4e91199130
Reviewed-on: https://chromium-review.googlesource.com/1179671
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55214}
This commit is contained in:
jgruber 2018-08-20 12:54:36 +02:00 committed by Commit Bot
parent 74004dbf3d
commit e2de46567a
1 changed files with 7 additions and 4 deletions
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11
src/wasm/wasm-code-manager.cc
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@ -199,7 +199,6 @@ void WasmCode::Validate() const {
}
case RelocInfo::JS_TO_WASM_CALL:
case RelocInfo::EXTERNAL_REFERENCE:
case RelocInfo::OFF_HEAP_TARGET:
case RelocInfo::COMMENT:
case RelocInfo::CONST_POOL:
case RelocInfo::VENEER_POOL:
@ -444,9 +443,13 @@ void NativeModule::SetRuntimeStubs(Isolate* isolate) {
WasmCode* NativeModule::AddAnonymousCode(Handle<Code> code,
WasmCode::Kind kind) {
OwnedVector<byte> reloc_info =
OwnedVector<byte>::New(code->relocation_size());
memcpy(reloc_info.start(), code->relocation_start(), code->relocation_size());
// For off-heap builtins, we create a copy of the off-heap instruction stream
// instead of the on-heap code object containing the trampoline. Ensure that
// we do not apply the on-heap reloc info to the off-heap instructions.
const size_t relocation_size =
code->is_off_heap_trampoline() ? 0 : code->relocation_size();
OwnedVector<byte> reloc_info = OwnedVector<byte>::New(relocation_size);
memcpy(reloc_info.start(), code->relocation_start(), relocation_size);
Handle<ByteArray> source_pos_table(code->SourcePositionTable(),
code->GetIsolate());
OwnedVector<byte> source_pos =