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[wasm] Introduce --wasm-enforce-bounds-checks flag

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There currently is no way to enforce explicit bounds checks if the
embedder installed the signal handler for wasm trap handling (queried
via {trap_handler::IsTrapHandlerEnabled()}).
This CL adds a respective flag and makes all compilation emit explicit
bounds checks if it is disabled.

R=ahaas@chromium.org

Bug: v8:11926
Change-Id: Ie19faab1766d3105f3c22cb4470c0f15398f1d09
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2989129
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75453}
This commit is contained in:
Clemens Backes 2021-06-25 19:33:13 +02:00 committed by V8 LUCI CQ
parent fe8f3e6fd6
commit e6371af86a
8 changed files with 30 additions and 20 deletions
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2
src/compiler/backend/arm64/code-generator-arm64.cc
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@ -437,7 +437,7 @@ class WasmProtectedInstructionTrap final : public WasmOutOfLineTrap {
: WasmOutOfLineTrap(gen, instr), pc_(pc) {}
void Generate() override {
DCHECK(FLAG_wasm_bounds_checks && FLAG_wasm_trap_handler);
DCHECK(FLAG_wasm_bounds_checks && !FLAG_wasm_enforce_bounds_checks);
gen_->AddProtectedInstructionLanding(pc_, __ pc_offset());
GenerateWithTrapId(TrapId::kTrapMemOutOfBounds);
}

2
src/compiler/backend/x64/code-generator-x64.cc
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@ -543,7 +543,7 @@ class WasmProtectedInstructionTrap final : public WasmOutOfLineTrap {
: WasmOutOfLineTrap(gen, instr), pc_(pc) {}
void Generate() final {
DCHECK(FLAG_wasm_bounds_checks && FLAG_wasm_trap_handler);
DCHECK(FLAG_wasm_bounds_checks && !FLAG_wasm_enforce_bounds_checks);
gen_->AddProtectedInstructionLanding(pc_, __ pc_offset());
GenerateWithTrapId(TrapId::kTrapMemOutOfBounds);
}

7
src/flags/flag-definitions.h
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@ -1021,6 +1021,11 @@ DEFINE_BOOL(
"enable bounds checks (disable for performance testing only)")
DEFINE_BOOL(wasm_stack_checks, true,
"enable stack checks (disable for performance testing only)")
DEFINE_BOOL(
wasm_enforce_bounds_checks, false,
"enforce explicit bounds check even if the trap handler is available")
// "no bounds checks" implies "no enforced bounds checks".
DEFINE_NEG_NEG_IMPLICATION(wasm_bounds_checks, wasm_enforce_bounds_checks)
DEFINE_BOOL(wasm_math_intrinsics, true,
"intrinsify some Math imports into wasm")
@ -1029,8 +1034,6 @@ DEFINE_BOOL(wasm_loop_unrolling, true,
DEFINE_BOOL(wasm_trap_handler, true,
"use signal handlers to catch out of bounds memory access in wasm"
" (currently Linux x86_64 only)")
// "no bounds checks" implies "no trap handlers".
DEFINE_NEG_NEG_IMPLICATION(wasm_bounds_checks, wasm_trap_handler)
DEFINE_BOOL(wasm_fuzzer_gen_test, false,
"generate a test case when running a wasm fuzzer")
DEFINE_IMPLICATION(wasm_fuzzer_gen_test, single_threaded)

7
src/wasm/wasm-code-manager.cc
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@ -847,8 +847,11 @@ NativeModule::NativeModule(const WasmFeatures& enabled,
module_(std::move(module)),
import_wrapper_cache_(std::unique_ptr<WasmImportWrapperCache>(
new WasmImportWrapperCache())),
use_trap_handler_(trap_handler::IsTrapHandlerEnabled() ? kUseTrapHandler
: kNoTrapHandler) {
// TODO(clemensb): Rename this field.
use_trap_handler_(trap_handler::IsTrapHandlerEnabled() &&
!FLAG_wasm_enforce_bounds_checks
? kUseTrapHandler
: kNoTrapHandler) {
DCHECK(engine_scope_);
// We receive a pointer to an empty {std::shared_ptr}, and install ourselve
// there.

8
test/cctest/cctest.cc
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@ -344,11 +344,9 @@ int main(int argc, char* argv[]) {
v8::V8::InitializeExternalStartupData(argv[0]);
#if V8_ENABLE_WEBASSEMBLY && V8_TRAP_HANDLER_SUPPORTED
if (i::FLAG_wasm_trap_handler) {
constexpr bool use_default_signal_handler = true;
CHECK(v8::V8::EnableWebAssemblyTrapHandler(use_default_signal_handler));
}
#endif // V8_TRAP_HANDLER_SUPPORTED && V8_ENABLE_WEBASSEMBLY
constexpr bool kUseDefaultTrapHandler = true;
CHECK(v8::V8::EnableWebAssemblyTrapHandler(kUseDefaultTrapHandler));
#endif // V8_ENABLE_WEBASSEMBLY && V8_TRAP_HANDLER_SUPPORTED
CcTest::set_array_buffer_allocator(
v8::ArrayBuffer::Allocator::NewDefaultAllocator());

9
test/cctest/wasm/test-run-wasm-atomics.cc
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@ -319,7 +319,8 @@ WASM_EXEC_TEST(AtomicFence) {
WASM_EXEC_TEST(AtomicStoreNoConsideredEffectful) {
EXPERIMENTAL_FLAG_SCOPE(threads);
FLAG_wasm_trap_handler = false; // To use {Load} instead of {ProtectedLoad}.
// Use {Load} instead of {ProtectedLoad}.
FLAG_SCOPE(wasm_enforce_bounds_checks);
WasmRunner<uint32_t> r(execution_tier);
r.builder().AddMemoryElems<int32_t>(kWasmPageSize / sizeof(int32_t));
r.builder().SetHasSharedMemory();
@ -332,7 +333,8 @@ WASM_EXEC_TEST(AtomicStoreNoConsideredEffectful) {
void RunNoEffectTest(TestExecutionTier execution_tier, WasmOpcode wasm_op) {
EXPERIMENTAL_FLAG_SCOPE(threads);
FLAG_wasm_trap_handler = false; // To use {Load} instead of {ProtectedLoad}.
// Use {Load} instead of {ProtectedLoad}.
FLAG_SCOPE(wasm_enforce_bounds_checks);
WasmRunner<uint32_t> r(execution_tier);
r.builder().AddMemoryElems<int32_t>(kWasmPageSize / sizeof(int32_t));
r.builder().SetHasSharedMemory();
@ -353,7 +355,8 @@ WASM_EXEC_TEST(AtomicExchangeNoConsideredEffectful) {
WASM_EXEC_TEST(AtomicCompareExchangeNoConsideredEffectful) {
EXPERIMENTAL_FLAG_SCOPE(threads);
FLAG_wasm_trap_handler = false; // To use {Load} instead of {ProtectedLoad}.
// Use {Load} instead of {ProtectedLoad}.
FLAG_SCOPE(wasm_enforce_bounds_checks);
WasmRunner<uint32_t> r(execution_tier);
r.builder().AddMemoryElems<int32_t>(kWasmPageSize / sizeof(int32_t));
r.builder().SetHasSharedMemory();

9
test/cctest/wasm/test-run-wasm-atomics64.cc
View File

@ -648,7 +648,8 @@ WASM_EXEC_TEST(I64AtomicCompareExchange32UFail) {
WASM_EXEC_TEST(AtomicStoreNoConsideredEffectful) {
EXPERIMENTAL_FLAG_SCOPE(threads);
FLAG_wasm_trap_handler = false; // To use {Load} instead of {ProtectedLoad}.
// Use {Load} instead of {ProtectedLoad}.
FLAG_SCOPE(wasm_enforce_bounds_checks);
WasmRunner<uint32_t> r(execution_tier);
r.builder().AddMemoryElems<int64_t>(kWasmPageSize / sizeof(int64_t));
r.builder().SetHasSharedMemory();
@ -661,7 +662,8 @@ WASM_EXEC_TEST(AtomicStoreNoConsideredEffectful) {
void RunNoEffectTest(TestExecutionTier execution_tier, WasmOpcode wasm_op) {
EXPERIMENTAL_FLAG_SCOPE(threads);
FLAG_wasm_trap_handler = false; // To use {Load} instead of {ProtectedLoad}.
// Use {Load} instead of {ProtectedLoad}.
FLAG_SCOPE(wasm_enforce_bounds_checks);
WasmRunner<uint32_t> r(execution_tier);
r.builder().AddMemoryElems<int64_t>(kWasmPageSize / sizeof(int64_t));
r.builder().SetHasSharedMemory();
@ -682,7 +684,8 @@ WASM_EXEC_TEST(AtomicExchangeNoConsideredEffectful) {
WASM_EXEC_TEST(AtomicCompareExchangeNoConsideredEffectful) {
EXPERIMENTAL_FLAG_SCOPE(threads);
FLAG_wasm_trap_handler = false; // To use {Load} instead of {ProtectedLoad}.
// Use {Load} instead of {ProtectedLoad}.
FLAG_SCOPE(wasm_enforce_bounds_checks);
WasmRunner<uint32_t> r(execution_tier);
r.builder().AddMemoryElems<uint64_t>(kWasmPageSize / sizeof(uint64_t));
r.builder().SetHasSharedMemory();

6
test/cctest/wasm/wasm-run-utils.cc
View File

@ -314,10 +314,10 @@ uint32_t TestingModuleBuilder::AddPassiveElementSegment(
CompilationEnv TestingModuleBuilder::CreateCompilationEnv() {
// This is a hack so we don't need to call
// trap_handler::IsTrapHandlerEnabled().
const bool is_trap_handler_enabled =
V8_TRAP_HANDLER_SUPPORTED && i::FLAG_wasm_trap_handler;
const bool use_trap_handler =
V8_TRAP_HANDLER_SUPPORTED && !i::FLAG_wasm_enforce_bounds_checks;
return {test_module_.get(),
is_trap_handler_enabled ? kUseTrapHandler : kNoTrapHandler,
use_trap_handler ? kUseTrapHandler : kNoTrapHandler,
runtime_exception_support_, enabled_features_};
}