[wasm] Introduce performance testing options.

Adds --wasm-no-bounds-checks and --wasm-no-stack-checks which
help in diagnosing potential sources of slowdown in WASM code.

R=ahaas@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2511113002
Cr-Commit-Position: refs/heads/master@{#41083}

src/compiler/wasm-compiler.cc

@@ -412,6 +412,7 @@ Node* WasmGraphBuilder::Int64Constant(int64_t value) {
 
 void WasmGraphBuilder::StackCheck(wasm::WasmCodePosition position,
                                   Node** effect, Node** control) {
+  if (FLAG_wasm_no_stack_checks) return;
   if (effect == nullptr) {
     effect = effect_;
   }
@@ -2895,6 +2896,7 @@ void WasmGraphBuilder::BoundsCheckMem(MachineType memtype, Node* index,
                                       uint32_t offset,
                                       wasm::WasmCodePosition position) {
   DCHECK(module_ && module_->instance);
+  if (FLAG_wasm_no_bounds_checks) return;
   uint32_t size = module_->instance->mem_size;
   byte memsize = wasm::WasmOpcodes::MemSize(memtype);
 

src/flag-definitions.h

@@ -522,6 +522,11 @@ DEFINE_BOOL(wasm_mv_prototype, false,
 DEFINE_BOOL(wasm_atomics_prototype, false,
             "enable prototype atomic opcodes for wasm")
 
+DEFINE_BOOL(wasm_no_bounds_checks, false,
+            "disable bounds checks (performance testing only)")
+DEFINE_BOOL(wasm_no_stack_checks, false,
+            "disable stack checks (performance testing only)")
+
 DEFINE_BOOL(wasm_trap_handler, false,
             "use signal handlers to catch out of bounds memory access in wasm"
             " (currently Linux x86_64 only)")