[no-wasm] Exclude trap-handler implementation

The trap handler is only needed for WebAssembly, hence it can be
excluded in no-wasm builds (v8_enable_webassembly = false).
This makes it easier to port WebAssembly to platforms that do not need
to support WebAssembly.

R=ahaas@chromium.org, jkummerow@chromium.org
CC=johnx@google.com

Bug: v8:11877
Change-Id: I25c34c2c4f1122227047e13add532ee2b9f73d2f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2953285Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75101}

BUILD.gn

@@ -3103,8 +3103,6 @@ v8_header_set("v8_internal_headers") {
     "src/tracing/trace-event.h",
     "src/tracing/traced-value.h",
     "src/tracing/tracing-category-observer.h",
-    "src/trap-handler/trap-handler-internal.h",
-    "src/trap-handler/trap-handler.h",
     "src/utils/address-map.h",
     "src/utils/allocation.h",
     "src/utils/bit-vector.h",
@@ -3152,6 +3150,8 @@ v8_header_set("v8_internal_headers") {
       "src/compiler/wasm-compiler.h",
       "src/debug/debug-wasm-objects-inl.h",
       "src/debug/debug-wasm-objects.h",
+      "src/trap-handler/trap-handler-internal.h",
+      "src/trap-handler/trap-handler.h",
       "src/wasm/baseline/liftoff-assembler-defs.h",
       "src/wasm/baseline/liftoff-assembler.h",
       "src/wasm/baseline/liftoff-compiler.h",
@@ -3294,16 +3294,19 @@ v8_header_set("v8_internal_headers") {
       "src/wasm/baseline/x64/liftoff-assembler-x64.h",
     ]
 
-    # iOS Xcode simulator builds run on an x64 target. iOS and macOS are both
-    # based on Darwin and thus POSIX-compliant to a similar degree.
-    if (is_linux || is_chromeos || is_mac || is_ios || target_os == "freebsd") {
-      sources += [ "src/trap-handler/handler-inside-posix.h" ]
-    }
     if (is_win) {
-      sources += [
-        "src/diagnostics/unwinding-info-win64.h",
-        "src/trap-handler/handler-inside-win.h",
-      ]
+      sources += [ "src/diagnostics/unwinding-info-win64.h" ]
+    }
+
+    if (v8_enable_webassembly) {
+      # iOS Xcode simulator builds run on an x64 target. iOS and macOS are both
+      # based on Darwin and thus POSIX-compliant to a similar degree.
+      if (is_linux || is_chromeos || is_mac || is_ios ||
+          target_os == "freebsd") {
+        sources += [ "src/trap-handler/handler-inside-posix.h" ]
+      } else if (is_win) {
+        sources += [ "src/trap-handler/handler-inside-win.h" ]
+      }
     }
   } else if (v8_current_cpu == "arm") {
     sources += [  ### gcmole(arch:arm) ###
@@ -3348,7 +3351,7 @@ v8_header_set("v8_internal_headers") {
     if (v8_control_flow_integrity) {
       sources += [ "src/execution/arm64/pointer-authentication-arm64.h" ]
     }
-    if (current_cpu == "arm64" && is_mac) {
+    if (v8_enable_webassembly && current_cpu == "arm64" && is_mac) {
       sources += [ "src/trap-handler/handler-inside-posix.h" ]
     }
     if (is_win) {
@@ -4068,9 +4071,6 @@ v8_source_set("v8_base_without_compiler") {
     "src/tracing/trace-event.cc",
     "src/tracing/traced-value.cc",
     "src/tracing/tracing-category-observer.cc",
-    "src/trap-handler/handler-inside.cc",
-    "src/trap-handler/handler-outside.cc",
-    "src/trap-handler/handler-shared.cc",
     "src/utils/address-map.cc",
     "src/utils/allocation.cc",
     "src/utils/bit-vector.cc",
@@ -4097,6 +4097,9 @@ v8_source_set("v8_base_without_compiler") {
       "src/debug/debug-wasm-objects.cc",
       "src/runtime/runtime-test-wasm.cc",
       "src/runtime/runtime-wasm.cc",
+      "src/trap-handler/handler-inside.cc",
+      "src/trap-handler/handler-outside.cc",
+      "src/trap-handler/handler-shared.cc",
       "src/wasm/baseline/liftoff-assembler.cc",
       "src/wasm/baseline/liftoff-compiler.cc",
       "src/wasm/function-body-decoder.cc",
@@ -4193,20 +4196,25 @@ v8_source_set("v8_base_without_compiler") {
       "src/regexp/x64/regexp-macro-assembler-x64.cc",
     ]
 
-    # iOS Xcode simulator builds run on an x64 target. iOS and macOS are both
-    # based on Darwin and thus POSIX-compliant to a similar degree.
-    if (is_linux || is_chromeos || is_mac || is_ios || target_os == "freebsd") {
-      sources += [
-        "src/trap-handler/handler-inside-posix.cc",
-        "src/trap-handler/handler-outside-posix.cc",
-      ]
-    }
     if (is_win) {
-      sources += [
-        "src/diagnostics/unwinding-info-win64.cc",
-        "src/trap-handler/handler-inside-win.cc",
-        "src/trap-handler/handler-outside-win.cc",
-      ]
+      sources += [ "src/diagnostics/unwinding-info-win64.cc" ]
+    }
+
+    if (v8_enable_webassembly) {
+      # iOS Xcode simulator builds run on an x64 target. iOS and macOS are both
+      # based on Darwin and thus POSIX-compliant to a similar degree.
+      if (is_linux || is_chromeos || is_mac || is_ios ||
+          target_os == "freebsd") {
+        sources += [
+          "src/trap-handler/handler-inside-posix.cc",
+          "src/trap-handler/handler-outside-posix.cc",
+        ]
+      } else if (is_win) {
+        sources += [
+          "src/trap-handler/handler-inside-win.cc",
+          "src/trap-handler/handler-outside-win.cc",
+        ]
+      }
     }
   } else if (v8_current_cpu == "arm") {
     sources += [  ### gcmole(arch:arm) ###
@@ -4250,7 +4258,7 @@ v8_source_set("v8_base_without_compiler") {
       "src/execution/arm64/simulator-logic-arm64.cc",
       "src/regexp/arm64/regexp-macro-assembler-arm64.cc",
     ]
-    if (current_cpu == "arm64" && is_mac) {
+    if (v8_enable_webassembly && current_cpu == "arm64" && is_mac) {
       sources += [
         "src/trap-handler/handler-inside-posix.cc",
         "src/trap-handler/handler-outside-posix.cc",

src/api/api.cc

@@ -109,11 +109,11 @@
 #include "src/strings/string-hasher.h"
 #include "src/strings/unicode-inl.h"
 #include "src/tracing/trace-event.h"
-#include "src/trap-handler/trap-handler.h"
 #include "src/utils/detachable-vector.h"
 #include "src/utils/version.h"
 
 #if V8_ENABLE_WEBASSEMBLY
+#include "src/trap-handler/trap-handler.h"
 #include "src/wasm/streaming-decoder.h"
 #include "src/wasm/value-type.h"
 #include "src/wasm/wasm-engine.h"
@@ -5854,8 +5854,9 @@ bool TryHandleWebAssemblyTrapPosix(int sig_code, siginfo_t* info,
   // code rather than the wasm code, so the trap handler cannot find the landing
   // pad and lets the process crash. Therefore, only enable trap handlers if
   // the host and target arch are the same.
-#if (V8_TARGET_ARCH_X64 && !V8_OS_ANDROID) || \
-    (V8_HOST_ARCH_ARM64 && V8_TARGET_ARCH_ARM64 && V8_OS_MACOSX)
+#if V8_ENABLE_WEBASSEMBLY &&                   \
+    ((V8_TARGET_ARCH_X64 && !V8_OS_ANDROID) || \
+     (V8_HOST_ARCH_ARM64 && V8_TARGET_ARCH_ARM64 && V8_OS_MACOSX))
   return i::trap_handler::TryHandleSignal(sig_code, info, context);
 #else
   return false;
@@ -5870,15 +5871,20 @@ bool V8::TryHandleSignal(int signum, void* info, void* context) {
 
 #if V8_OS_WIN
 bool TryHandleWebAssemblyTrapWindows(EXCEPTION_POINTERS* exception) {
-#if V8_TARGET_ARCH_X64
+#if V8_ENABLE_WEBASSEMBLY && V8_TARGET_ARCH_X64
   return i::trap_handler::TryHandleWasmTrap(exception);
-#endif
+#else
   return false;
+#endif
 }
 #endif
 
 bool V8::EnableWebAssemblyTrapHandler(bool use_v8_signal_handler) {
+#if V8_ENABLE_WEBASSEMBLY && V8_TARGET_ARCH_X64
   return v8::internal::trap_handler::EnableTrapHandler(use_v8_signal_handler);
+#else
+  return false;
+#endif
 }
 
 #if defined(V8_OS_WIN)

src/execution/isolate.cc

@@ -92,7 +92,6 @@
 #include "src/strings/string-stream.h"
 #include "src/tasks/cancelable-task.h"
 #include "src/tracing/tracing-category-observer.h"
-#include "src/trap-handler/trap-handler.h"
 #include "src/utils/address-map.h"
 #include "src/utils/ostreams.h"
 #include "src/utils/version.h"
@@ -103,6 +102,7 @@
 #endif  // V8_INTL_SUPPORT
 
 #if V8_ENABLE_WEBASSEMBLY
+#include "src/trap-handler/trap-handler.h"
 #include "src/wasm/wasm-code-manager.h"
 #include "src/wasm/wasm-engine.h"
 #include "src/wasm/wasm-module.h"
@@ -1582,8 +1582,8 @@ Handle<JSMessageObject> Isolate::CreateMessageOrAbort(
 
 Object Isolate::ThrowInternal(Object raw_exception, MessageLocation* location) {
   DCHECK(!has_pending_exception());
-  DCHECK_IMPLIES(trap_handler::IsTrapHandlerEnabled(),
-                 !trap_handler::IsThreadInWasm());
+  IF_WASM(DCHECK_IMPLIES, trap_handler::IsTrapHandlerEnabled(),
+          !trap_handler::IsThreadInWasm());
 
   HandleScope scope(this);
   Handle<Object> exception(raw_exception, this);
@@ -1678,6 +1678,7 @@ Object Isolate::ReThrow(Object exception) {
 }
 
 namespace {
+#if V8_ENABLE_WEBASSEMBLY
 // This scope will set the thread-in-wasm flag after the execution of all
 // destructors. The thread-in-wasm flag is only set when the scope gets enabled.
 class SetThreadInWasmFlagScope {
@@ -1696,9 +1697,11 @@ class SetThreadInWasmFlagScope {
  private:
   bool enabled_ = false;
 };
+#endif  // V8_ENABLE_WEBASSEMBLY
 }  // namespace
 
 Object Isolate::UnwindAndFindHandler() {
+#if V8_ENABLE_WEBASSEMBLY
   // Create the {SetThreadInWasmFlagScope} first in this function so that its
   // destructor gets called after all the other destructors. It is important
   // that the destructor sets the thread-in-wasm flag after all other
@@ -1706,6 +1709,7 @@ Object Isolate::UnwindAndFindHandler() {
   // Windows, which would invalidate the thread-in-wasm flag when the wasm trap
   // handler handles such non-wasm exceptions.
   SetThreadInWasmFlagScope set_thread_in_wasm_flag_scope;
+#endif  // V8_ENABLE_WEBASSEMBLY
   Object exception = pending_exception();
 
   auto FoundHandler = [&](Context context, Address instruction_start,

src/execution/thread-local-top.cc

@@ -42,8 +42,10 @@ void ThreadLocalTop::Initialize(Isolate* isolate) {
   Clear();
   isolate_ = isolate;
   thread_id_ = ThreadId::Current();
+#if V8_ENABLE_WEBASSEMBLY
   thread_in_wasm_flag_address_ = reinterpret_cast<Address>(
       trap_handler::GetThreadInWasmThreadLocalAddress());
+#endif  // V8_ENABLE_WEBASSEMBLY
 #ifdef USE_SIMULATOR
   simulator_ = Simulator::current(isolate);
 #endif

src/objects/backing-store.cc

@@ -10,9 +10,9 @@
 #include "src/execution/isolate.h"
 #include "src/handles/global-handles.h"
 #include "src/logging/counters.h"
-#include "src/trap-handler/trap-handler.h"
 
 #if V8_ENABLE_WEBASSEMBLY
+#include "src/trap-handler/trap-handler.h"
 #include "src/wasm/wasm-constants.h"
 #include "src/wasm/wasm-engine.h"
 #include "src/wasm/wasm-limits.h"
@@ -349,7 +349,12 @@ std::unique_ptr<BackingStore> BackingStore::TryAllocateAndPartiallyCommitMemory(
 
   TRACE_BS("BSw:try   %zu pages, %zu max\n", initial_pages, maximum_pages);
 
+#if V8_ENABLE_WEBASSEMBLY
   bool guards = is_wasm_memory && trap_handler::IsTrapHandlerEnabled();
+#else
+  CHECK(!is_wasm_memory);
+  bool guards = false;
+#endif  // V8_ENABLE_WEBASSEMBLY
 
   // For accounting purposes, whether a GC was necessary.
   bool did_retry = false;