[wasm] Implement tracing of function calls

Added --trace-wasm flag which prints function entry in wasm.

R=clemensb@chromium.org

Bug: v8:10559
Change-Id: I049efeadb0149f4f58ce34a29fd53fbf5688bd4b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2215052
Commit-Queue: Arnaud Robin <arobin@google.com>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67998}

src/builtins/wasm.tq

@@ -21,6 +21,7 @@ extern runtime ReThrow(Context, Object): JSAny;
 extern runtime WasmStackGuard(Context): JSAny;
 extern runtime ThrowWasmStackOverflow(Context): JSAny;
 extern runtime WasmTraceMemory(Context, Smi): JSAny;
+extern runtime WasmTraceEnter(Context): JSAny;
 extern runtime WasmAtomicNotify(
     Context, WasmInstanceObject, Number, Number): Smi;
 extern runtime WasmI32AtomicWait(
@@ -210,6 +211,10 @@ builtin WasmTraceMemory(info: Smi): JSAny {
   tail runtime::WasmTraceMemory(LoadContextFromFrame(), info);
 }
 
+builtin WasmTraceEnter(): JSAny {
+  tail runtime::WasmTraceEnter(LoadContextFromFrame());
+}
+
 builtin WasmAllocateJSArray(implicit context: Context)(size: Smi): JSArray {
   const map: Map = GetFastPackedElementsJSArrayMap();
   return AllocateJSArray(ElementsKind::PACKED_ELEMENTS, map, size, size);

src/flags/flag-definitions.h

@@ -1149,7 +1149,8 @@ DEFINE_BOOL(inline_new, true, "use fast inline allocation")
 DEFINE_NEG_NEG_IMPLICATION(inline_new, turbo_allocation_folding)
 
 // codegen-ia32.cc / codegen-arm.cc
-DEFINE_BOOL(trace, false, "trace function calls")
+DEFINE_BOOL(trace, false, "trace javascript function calls")
+DEFINE_BOOL(trace_wasm, false, "trace wasm function calls")
 
 // codegen.cc
 DEFINE_BOOL(lazy, true, "use lazy compilation")

src/runtime/runtime-test.cc

@@ -952,7 +952,6 @@ RUNTIME_FUNCTION(Runtime_TraceEnter) {
   return ReadOnlyRoots(isolate).undefined_value();
 }
 
-
 RUNTIME_FUNCTION(Runtime_TraceExit) {
   SealHandleScope shs(isolate);
   DCHECK_EQ(1, args.length());
@@ -964,6 +963,14 @@ RUNTIME_FUNCTION(Runtime_TraceExit) {
   return obj;  // return TOS
 }
 
+RUNTIME_FUNCTION(Runtime_WasmTraceEnter) {
+  SealHandleScope shs(isolate);
+  DCHECK_EQ(0, args.length());
+  // TODO(10559): Print more useful info here.
+  PrintF("Enter function\n");
+  return ReadOnlyRoots(isolate).undefined_value();
+}
+
 RUNTIME_FUNCTION(Runtime_HaveSameMap) {
   SealHandleScope shs(isolate);
   DCHECK_EQ(2, args.length());

src/runtime/runtime.h

@@ -542,6 +542,7 @@ namespace internal {
   F(WasmTierDownModule, 1, 1)                 \
   F(WasmTierUpFunction, 2, 1)                 \
   F(WasmTierUpModule, 1, 1)                   \
+  F(WasmTraceEnter, 0, 1)                     \
   F(WasmTraceMemory, 1, 1)                    \
   I(DeoptimizeNow, 0, 1)
 

src/wasm/baseline/liftoff-compiler.cc

@@ -520,6 +520,14 @@ class LiftoffCompiler {
     return false;
   }
 
+  void TraceFunctionEntry(FullDecoder* decoder) {
+    DEBUG_CODE_COMMENT("trace function entry");
+    source_position_table_builder_.AddPosition(
+        __ pc_offset(), SourcePosition(decoder->position()), false);
+    __ CallRuntimeStub(WasmCode::kWasmTraceEnter);
+    safepoint_table_builder_.DefineSafepoint(&asm_, Safepoint::kNoLazyDeopt);
+  }
+
   void StartFunctionBody(FullDecoder* decoder, Control* block) {
     for (uint32_t i = 0; i < __ num_locals(); ++i) {
       if (!CheckSupportedType(decoder, kSupportedTypes, __ local_type(i),
@@ -594,6 +602,8 @@ class LiftoffCompiler {
     // is never a position of any instruction in the function.
     StackCheck(0);
 
+    if (FLAG_trace_wasm) TraceFunctionEntry(decoder);
+
     // If we are generating debug code, do check the "hook on function call"
     // flag. If set, trigger a break.
     if (V8_UNLIKELY(for_debugging_)) {

src/wasm/wasm-code-manager.h

@@ -71,6 +71,7 @@ struct WasmModule;
   V(WasmStackOverflow)                   \
   V(WasmThrow)                           \
   V(WasmRethrow)                         \
+  V(WasmTraceEnter)                      \
   V(WasmTraceMemory)                     \
   V(ArgumentsAdaptorTrampoline)          \
   V(BigIntToI32Pair)                     \

test/message/wasm-trace.js

+// Copyright 2020 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --trace-wasm --no-wasm-tier-up --liftoff --no-stress-opt
+
+load('test/mjsunit/wasm/wasm-module-builder.js');
+
+let builder = new WasmModuleBuilder();
+let kRet23Function = builder.addFunction('ret_23', kSig_i_v)
+                        .addBody([kExprI32Const, 23])
+                        .exportFunc()
+                        .index;
+builder.addFunction('main', kSig_v_v)
+    .addBody([kExprCallFunction, kRet23Function, kExprDrop])
+    .exportAs('main');
+
+let instance = builder.instantiate();
+instance.exports.main();

test/message/wasm-trace.out

+Enter function
+Enter function