Revert "[wasm] Add more unit tests for trap handler"

This reverts commit 4644b32e.

Reason for revert: Link errors on win64: https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8%20Win64%20-%20debug/25950

Original change's description:
> [wasm] Add more unit tests for trap handler
> 
> The unittests test if the trap handler only handles those traps it
> is supposed to handle:
> * Only handle traps when the thread-in-wasm flag is set.
> * Only handle traps of the right type, i.e. memory access violations.
> * Only handle traps at recorded instructions.
> 
> The tests also test the consistency of the thread-in-wasm flag. I made
> one change in the trap handler where that consistency could be
> violated.
> 
> All tests are executed with the default trap handler provided by V8,
> and with the trap handler callback installed in a test signal/exception
> handler.
> 
> Change-Id: I03904bb6effd2e8694d3f4d1fbf62bc38002646e
> Reviewed-on: https://chromium-review.googlesource.com/c/1340246
> Commit-Queue: Andreas Haas <ahaas@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#57858}

TBR=mstarzinger@chromium.org,ahaas@chromium.org,mark@chromium.org

Change-Id: Iac2f20c73744226885ea1810813863a21c5faf8c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/1351021Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57861}

src/trap-handler/handler-inside-posix.cc

@@ -72,17 +72,6 @@ class SigUnmaskStack {
 };
 
 bool TryHandleSignal(int signum, siginfo_t* info, void* context) {
-  // Ensure the faulting thread was actually running Wasm code. This should be
-  // the first check in the trap handler to guarantee that the IsThreadInWasm
-  // flag is only set in wasm code. Otherwise a later signal handler is executed
-  // with the flag set.
-  if (!IsThreadInWasm()) {
-    return false;
-  }
-
-  // Clear g_thread_in_wasm_code, primarily to protect against nested faults.
-  g_thread_in_wasm_code = false;
-
   // Bail out early in case we got called for the wrong kind of signal.
 
   if (signum != kOobSignal) {
@@ -94,6 +83,14 @@ bool TryHandleSignal(int signum, siginfo_t* info, void* context) {
     return false;
   }
 
+  // Ensure the faulting thread was actually running Wasm code.
+  if (!IsThreadInWasm()) {
+    return false;
+  }
+
+  // Clear g_thread_in_wasm_code, primarily to protect against nested faults.
+  g_thread_in_wasm_code = false;
+
   // Begin signal mask scope. We need to be sure to restore the signal mask
   // before we restore the g_thread_in_wasm_code flag.
   {

src/wasm/wasm-memory.cc

@@ -154,20 +154,6 @@ WasmMemoryTracker::~WasmMemoryTracker() {
   DCHECK_EQ(allocated_address_space_, 0u);
 }
 
-void* WasmMemoryTracker::TryAllocateBackingStoreForTesting(
-    Heap* heap, size_t size, void** allocation_base,
-    size_t* allocation_length) {
-  return TryAllocateBackingStore(this, heap, size, allocation_base,
-                                 allocation_length);
-}
-
-void WasmMemoryTracker::FreeBackingStoreForTesting(base::AddressRegion memory,
-                                                   void* buffer_start) {
-  ReleaseAllocation(nullptr, buffer_start);
-  CHECK(FreePages(GetPlatformPageAllocator(),
-                  reinterpret_cast<void*>(memory.begin()), memory.size()));
-}
-
 bool WasmMemoryTracker::ReserveAddressSpace(size_t num_bytes,
                                             ReservationLimit limit) {
   size_t reservation_limit =

src/wasm/wasm-memory.h

@@ -66,18 +66,6 @@ class WasmMemoryTracker {
     friend WasmMemoryTracker;
   };
 
-  // Allow tests to allocate a backing store the same way as we do it for
-  // WebAssembly memory. This is used in unit tests for trap handler to
-  // generate the same signals/exceptions for invalid memory accesses as
-  // we would get with WebAssembly memory.
-  void* TryAllocateBackingStoreForTesting(Heap* heap, size_t size,
-                                          void** allocation_base,
-                                          size_t* allocation_length);
-
-  // Free memory allocated with TryAllocateBackingStoreForTesting.
-  void FreeBackingStoreForTesting(base::AddressRegion memory,
-                                  void* buffer_start);
-
   // Decreases the amount of reserved address space.
   void ReleaseReservation(size_t num_bytes);
 

test/cctest/test-assembler-arm64.cc

@@ -209,7 +209,8 @@ static void InitializeVM() {
   __ Ret();                     \
   __ GetCode(masm.isolate(), nullptr);
 
-#define TEARDOWN() FreeAssemblerBuffer(buf, allocated);
+#define TEARDOWN() \
+  CHECK(v8::internal::FreePages(GetPlatformPageAllocator(), buf, allocated));
 
 #endif  // ifdef USE_SIMULATOR.
 

test/common/assembler-tester.h

@@ -23,10 +23,6 @@ static inline uint8_t* AllocateAssemblerBuffer(
   return static_cast<uint8_t*>(result);
 }
 
-static inline void FreeAssemblerBuffer(uint8_t* buffer, size_t size) {
-  CHECK(FreePages(GetPlatformPageAllocator(), buffer, size));
-}
-
 static inline void MakeAssemblerBufferExecutable(uint8_t* buffer,
                                                  size_t allocated) {
   // Flush the instruction cache as part of making the buffer executable.

test/unittests/BUILD.gn

@@ -254,7 +254,6 @@ v8_source_set("unittests_sources") {
     sources += [
       "assembler/turbo-assembler-x64-unittest.cc",
       "compiler/x64/instruction-selector-x64-unittest.cc",
-      "wasm/trap-handler-x64-unittest.cc",
     ]
   } else if (v8_current_cpu == "ppc" || v8_current_cpu == "ppc64") {
     sources += [