[runtime] ClobberDoubleRegisters rewritten in platform-specific assembly

Currently ClobberDoubleRegisters is implemented in C++ and is
not guaranteed to clobber all registers. Rewritten in assembly
to clobber all double registers

Bug: v8:11798
Change-Id: I11c09bd247c929d251e6e509ea5cc76b9981ea98
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3490715
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79380}

BUILD.bazel

@@ -1216,6 +1216,8 @@ filegroup(
         "src/execution/arguments-inl.h",
         "src/execution/arguments.cc",
         "src/execution/arguments.h",
+        "src/execution/clobber-registers.cc",
+        "src/execution/clobber-registers.h",
         "src/execution/encoded-c-signature.cc",
         "src/execution/encoded-c-signature.h",
         "src/execution/embedder-state.h",

BUILD.gn

@@ -2912,6 +2912,7 @@ v8_header_set("v8_internal_headers") {
     "src/diagnostics/unwinder.h",
     "src/execution/arguments-inl.h",
     "src/execution/arguments.h",
+    "src/execution/clobber-registers.h",
     "src/execution/embedder-state.h",
     "src/execution/encoded-c-signature.h",
     "src/execution/execution.h",
@@ -4171,6 +4172,7 @@ v8_source_set("v8_base_without_compiler") {
     "src/diagnostics/perf-jit.cc",
     "src/diagnostics/unwinder.cc",
     "src/execution/arguments.cc",
+    "src/execution/clobber-registers.cc",
     "src/execution/embedder-state.cc",
     "src/execution/encoded-c-signature.cc",
     "src/execution/execution.cc",

src/execution/arguments.cc

@@ -3,16 +3,3 @@
 // found in the LICENSE file.
 
 #include "src/execution/arguments.h"
-
-namespace v8 {
-namespace internal {
-
-double ClobberDoubleRegisters(double x1, double x2, double x3, double x4) {
-  // TODO(v8:11798): This clobbers only subset of registers depending on
-  // compiler, Rewrite this in assembly to really clobber all registers. GCC for
-  // ia32 uses the FPU and does not touch XMM registers.
-  return x1 * 1.01 + x2 * 2.02 + x3 * 3.03 + x4 * 4.04;
-}
-
-}  // namespace internal
-}  // namespace v8

src/execution/arguments.h

@@ -5,6 +5,7 @@
 #ifndef V8_EXECUTION_ARGUMENTS_H_
 #define V8_EXECUTION_ARGUMENTS_H_
 
+#include "src/execution/clobber-registers.h"
 #include "src/handles/handles.h"
 #include "src/logging/runtime-call-stats-scope.h"
 #include "src/objects/objects.h"
@@ -105,8 +106,6 @@ Handle<S> Arguments<T>::at(int index) const {
   return Handle<S>::cast(obj);
 }
 
-double ClobberDoubleRegisters(double x1, double x2, double x3, double x4);
-
 #ifdef DEBUG
 #define CLOBBER_DOUBLE_REGISTERS() ClobberDoubleRegisters(1, 2, 3, 4);
 #else

src/execution/clobber-registers.cc

@@ -0,0 +1,63 @@
+// Copyright 2022 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.
+#include "src/execution/clobber-registers.h"
+
+#include "src/base/build_config.h"
+
+#if V8_HOST_ARCH_ARM
+#include "src/codegen/arm/register-arm.h"
+#elif V8_HOST_ARCH_ARM64
+#include "src/codegen/arm64/register-arm64.h"
+#elif V8_HOST_ARCH_IA32
+#include "src/codegen/ia32/register-ia32.h"
+#elif V8_HOST_ARCH_X64
+#include "src/codegen/x64/register-x64.h"
+#endif
+
+namespace v8 {
+namespace internal {
+
+#if V8_CC_MSVC
+// msvc only support inline assembly on x86
+#if V8_HOST_ARCH_IA32
+#define CLOBBER_REGISTER(R) __asm xorps R, R
+
+#endif
+
+#else  // !V8_CC_MSVC
+
+#if V8_HOST_ARCH_X64 || V8_HOST_ARCH_IA32
+#define CLOBBER_REGISTER(R) \
+  __asm__ volatile(         \
+      "xorps "              \
+      "%%" #R               \
+      ","                   \
+      "%%" #R ::            \
+          :);
+
+#elif V8_HOST_ARCH_ARM64
+#define CLOBBER_REGISTER(R) __asm__ volatile("fmov " #R ",xzr" :::);
+
+#endif  // V8_HOST_ARCH_X64 || V8_HOST_ARCH_IA32 || V8_HOST_ARCH_ARM64
+
+#endif  // V8_CC_MSVC
+
+double ClobberDoubleRegisters(double x1, double x2, double x3, double x4) {
+  // clobber all double registers
+
+#ifdef CLOBBER_REGISTER
+  DOUBLE_REGISTERS(CLOBBER_REGISTER)
+#undef CLOBBER_REGISTER
+  return 0;
+
+#else
+  // TODO(v8:11798): This clobbers only subset of registers depending on
+  // compiler, Rewrite this in assembly to really clobber all registers. GCC for
+  // ia32 uses the FPU and does not touch XMM registers.
+  return x1 * 1.01 + x2 * 2.02 + x3 * 3.03 + x4 * 4.04;
+#endif  // CLOBBER_REGISTER
+}
+
+}  // namespace internal
+}  // namespace v8

src/execution/clobber-registers.h

@@ -0,0 +1,18 @@
+
+// Copyright 2022 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.
+
+#ifndef V8_EXECUTION_CLOBBER_REGISTERS_H_
+#define V8_EXECUTION_CLOBBER_REGISTERS_H_
+
+namespace v8 {
+
+namespace internal {
+
+double ClobberDoubleRegisters(double x1, double x2, double x3, double x4);
+
+}
+}  // namespace v8
+
+#endif  // V8_EXECUTION_CLOBBER_REGISTERS_H_