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[wasm] Lazy-compilation: Support exporting an import

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When exporting an imported wasm function, we generate a js-to-wasm
wrapper which calls the wasm-to-wasm wrapper (which then tail-calls
the WasmCompileLazy stub).
This wasm-to-wasm wrapper also needs to be patched.

R=titzer@chromium.org

Bug: chromium:788441, v8:5991
Change-Id: Ibf27618a0511851cb55714b720fe7299a21c2959
Reviewed-on: https://chromium-review.googlesource.com/795990
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49715}
This commit is contained in:
Clemens Hammacher 2017-11-29 13:50:36 +01:00 committed by Commit Bot
parent 0d5b0d7365
commit 690ac5760c
2 changed files with 32 additions and 15 deletions
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33
src/wasm/module-compiler.cc
View File

@ -1041,9 +1041,9 @@ Handle<Code> LazyCompilationOrchestrator::CompileLazyOnGCHeap(
// remember that code object.
Handle<Code> wasm_to_wasm_callee;
if (is_js_to_wasm) {
non_compiled_functions.push_back({0, exported_func_index});
} else if (patch_caller) {
// For js-to-wasm wrappers, don't iterate the reloc info. There is just one
// call site in there anyway.
if (patch_caller && !is_js_to_wasm) {
DisallowHeapAllocation no_gc;
SourcePositionTableIterator source_pos_iterator(
caller->SourcePositionTable());
@ -1111,7 +1111,7 @@ Handle<Code> LazyCompilationOrchestrator::CompileLazyOnGCHeap(
isolate);
DCHECK_EQ(Code::WASM_FUNCTION, compiled_function->kind());
if (is_js_to_wasm || patch_caller) {
if (patch_caller || is_js_to_wasm) {
DisallowHeapAllocation no_gc;
// TODO(6792): No longer needed once WebAssembly code is off heap.
CodeSpaceMemoryModificationScope modification_scope(isolate->heap());
@ -1124,27 +1124,30 @@ Handle<Code> LazyCompilationOrchestrator::CompileLazyOnGCHeap(
Code::GetCodeFromTargetAddress(it.rinfo()->target_address());
if (callee->builtin_index() != Builtins::kWasmCompileLazy) {
// If the callee is the wasm-to-wasm wrapper triggering this lazy
// compilation, patch it.
if (!wasm_to_wasm_callee.is_null() && callee == *wasm_to_wasm_callee) {
// compilation, patch it. If is_js_to_wasm is set, we did not set the
// wasm_to_wasm_callee, so just check the code kind (this is the only
// call in that wrapper anyway).
if ((is_js_to_wasm && callee->kind() == Code::WASM_TO_WASM_FUNCTION) ||
(!wasm_to_wasm_callee.is_null() &&
callee == *wasm_to_wasm_callee)) {
TRACE_LAZY("Patching wasm-to-wasm wrapper.\n");
PatchWasmToWasmWrapper(isolate, callee, *compiled_function);
++patched;
}
continue;
}
DCHECK_GT(non_compiled_functions.size(), idx);
int called_func_index = non_compiled_functions[idx].func_index;
int called_func_index = func_to_return_idx;
if (!is_js_to_wasm) {
DCHECK_GT(non_compiled_functions.size(), idx);
called_func_index = non_compiled_functions[idx].func_index;
DCHECK_EQ(non_compiled_functions[idx].offset,
it.rinfo()->pc() - caller->instruction_start());
++idx;
}
// Check that the callee agrees with our assumed called_func_index.
DCHECK_IMPLIES(callee->deoptimization_data()->length() > 0,
Smi::ToInt(callee->deoptimization_data()->get(1)) ==
called_func_index);
if (is_js_to_wasm) {
DCHECK_EQ(func_to_return_idx, called_func_index);
} else {
DCHECK_EQ(non_compiled_functions[idx].offset,
it.rinfo()->pc() - caller->instruction_start());
}
++idx;
Handle<Code> callee_compiled(
Code::cast(compiled_module->code_table()->get(called_func_index)));
if (callee_compiled->builtin_index() == Builtins::kWasmCompileLazy) {

14
test/mjsunit/wasm/lazy-compilation.js
View File

@ -47,3 +47,17 @@ load('test/mjsunit/wasm/wasm-module-builder.js');
assertEquals(3, mem1[0]);
assertEquals(0, mem2[0]);
})();
(function exportImportedFunction() {
print(arguments.callee.name);
const builder1 = new WasmModuleBuilder();
builder1.addFunction('foo', kSig_v_v).addBody([]).exportAs('foo');
const instance1 = builder1.instantiate();
const builder2 = new WasmModuleBuilder();
const imp_idx = builder2.addImport('A', 'foo', kSig_v_v);
builder2.addExport('foo', imp_idx);
const instance2 = builder2.instantiate({A: instance1.exports});
instance2.exports.foo();
})();