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[wasm] Simplify interpreter {ThreadImpl::DoStackTransfer}.

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R=ahaas@chromium.org
BUG=v8:9183

Change-Id: Id8fbe12e6972ba22ee3974ec5bbbcfc1d4cb7458
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1612906
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61528}
This commit is contained in:
Michael Starzinger 2019-05-15 14:20:35 +02:00 committed by Commit Bot
parent 6c03d6bb7a
commit 163f3d0906
1 changed files with 25 additions and 26 deletions
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51
src/wasm/wasm-interpreter.cc
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@ -1503,14 +1503,14 @@ class ThreadImpl {
int JumpToHandlerDelta(InterpreterCode* code, pc_t pc) {
ControlTransferEntry& control_transfer_entry = code->side_table->Lookup(pc);
DoStackTransfer(sp_ - (control_transfer_entry.sp_diff + kCatchInArity),
DoStackTransfer(control_transfer_entry.sp_diff + kCatchInArity,
control_transfer_entry.target_arity);
return control_transfer_entry.pc_diff;
}
int DoBreak(InterpreterCode* code, pc_t pc, size_t depth) {
ControlTransferEntry& control_transfer_entry = code->side_table->Lookup(pc);
DoStackTransfer(sp_ - control_transfer_entry.sp_diff,
DoStackTransfer(control_transfer_entry.sp_diff,
control_transfer_entry.target_arity);
return control_transfer_entry.pc_diff;
}
@ -1534,12 +1534,12 @@ class ThreadImpl {
bool DoReturn(Decoder* decoder, InterpreterCode** code, pc_t* pc, pc_t* limit,
size_t arity) {
DCHECK_GT(frames_.size(), 0);
StackValue* sp_dest = stack_.get() + frames_.back().sp;
spdiff_t sp_diff = static_cast<spdiff_t>(StackHeight() - frames_.back().sp);
frames_.pop_back();
if (frames_.size() == current_activation().fp) {
// A return from the last frame terminates the execution.
state_ = WasmInterpreter::FINISHED;
DoStackTransfer(sp_dest, arity);
DoStackTransfer(sp_diff, arity);
TRACE(" => finish\n");
return false;
} else {
@ -1551,7 +1551,7 @@ class ThreadImpl {
*limit = top->code->end - top->code->start;
TRACE(" => Return to #%zu (#%u @%zu)\n", frames_.size() - 1,
(*code)->function->func_index, *pc);
DoStackTransfer(sp_dest, arity);
DoStackTransfer(sp_diff, arity);
return true;
}
}
@ -1582,10 +1582,10 @@ class ThreadImpl {
Frame* top = &frames_.back();
// Drop everything except current parameters.
StackValue* sp_dest = stack_.get() + top->sp;
spdiff_t sp_diff = static_cast<spdiff_t>(StackHeight() - top->sp);
size_t arity = target->function->sig->parameter_count();
DoStackTransfer(sp_dest, arity);
DoStackTransfer(sp_diff, arity);
*limit = target->end - target->start;
decoder->Reset(target->start, target->end);
@ -1604,30 +1604,29 @@ class ThreadImpl {
return true;
}
// Copies {arity} values on the top of the stack down the stack to {dest},
// dropping the values in-between.
void DoStackTransfer(StackValue* dest, size_t arity) {
// Copies {arity} values on the top of the stack down the stack while also
// dropping {sp_diff} many stack values in total from the stack.
void DoStackTransfer(spdiff_t sp_diff, size_t arity) {
// before: |---------------| pop_count | arity |
// ^ 0 ^ dest ^ sp_
// ^ 0 ^ dest ^ src ^ StackHeight()
// ^----< sp_diff >----^
//
// after: |---------------| arity |
// ^ 0 ^ sp_
DCHECK_LE(dest, sp_);
DCHECK_LE(dest + arity, sp_);
if (arity && (dest != sp_ - arity)) {
memmove(dest, sp_ - arity, arity * sizeof(*sp_));
// ^ 0 ^ StackHeight()
sp_t stack_height = StackHeight();
sp_t dest = stack_height - sp_diff;
sp_t src = stack_height - arity;
DCHECK_LE(dest, stack_height);
DCHECK_LE(dest, src);
if (arity && (dest != src)) {
StackValue* stack = stack_.get();
memmove(stack + dest, stack + src, arity * sizeof(StackValue));
// Also move elements on the reference stack accordingly.
// TODO(mstarzinger): Refactor the interface so that we don't have to
// recompute values here which are already known at the call-site.
int dst = static_cast<int>(StackHeight() - (sp_ - dest));
int src = static_cast<int>(StackHeight() - arity);
int len = static_cast<int>(arity);
reference_stack().MoveElements(isolate_, dst, src, len,
UPDATE_WRITE_BARRIER);
reference_stack().MoveElements(
isolate_, static_cast<int>(dest), static_cast<int>(src),
static_cast<int>(arity), UPDATE_WRITE_BARRIER);
}
// TODO(mstarzinger): Refactor the interface so that we don't have to
// recompute values here which are already known at the call-site.
ResetStack(StackHeight() - (sp_ - dest) + arity);
ResetStack(dest + arity);
}
inline Address EffectiveAddress(uint32_t index) {