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[wasm] Use PC after EnsureSpace in RecordProtectedInstruction

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Previously we captured the PC before calling EnsureSpace in
RecordProtectedInstruction. Sometimes EnsureSpace would resize and move
the buffer, which would invalidate the previously captured PC and trip an
assert when writing RelocInfo. With this change, we do not capture the PC
until after we've ensured there's enough space, which ensures the PC will
be valid.

BUG=

Review-Url: https://codereview.chromium.org/2690523003
Cr-Commit-Position: refs/heads/master@{#43202}
This commit is contained in:
eholk 2017-02-14 11:11:00 -08:00 committed by Commit bot
parent c7eabee422
commit c9e83ebc39
3 changed files with 4 additions and 6 deletions
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4
src/compiler/x64/code-generator-x64.cc
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@ -280,9 +280,7 @@ class WasmOutOfLineTrap final : public OutOfLineCode {
// TODO(eholk): Refactor this method to take the code generator as a
// parameter.
void Generate() final {
Address current_pc = __ pc();
__ RecordProtectedInstruction(pc_, current_pc);
__ RecordProtectedInstructionLanding(pc_);
if (frame_elided_) {
__ EnterFrame(StackFrame::WASM_COMPILED);

4
src/x64/assembler-x64.cc
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@ -4669,9 +4669,9 @@ void Assembler::emit_sse_operand(XMMRegister dst) {
emit(0xD8 | dst.low_bits());
}
void Assembler::RecordProtectedInstruction(int pc_offset, byte* landing) {
void Assembler::RecordProtectedInstructionLanding(int pc_offset) {
EnsureSpace ensure_space(this);
RelocInfo rinfo(isolate(), landing,
RelocInfo rinfo(isolate(), pc(),
RelocInfo::WASM_PROTECTED_INSTRUCTION_LANDING, pc_offset,
nullptr);
reloc_info_writer.Write(&rinfo);

2
src/x64/assembler-x64.h
View File

@ -1993,7 +1993,7 @@ class Assembler : public AssemblerBase {
UNREACHABLE();
}
void RecordProtectedInstruction(int pc_offset, byte* landing_offset);
void RecordProtectedInstructionLanding(int pc_offset);
// Writes a single word of data in the code stream.
// Used for inline tables, e.g., jump-tables.