x86 validator: Rewrite non-temporal stores into cached memory accesses

tests/validator/rewrite_nontemporals.c

+/*
+ * Copyright 2016 The Native Client 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 <string.h>
+
+#include "native_client/src/include/nacl_assert.h"
+
+char g_src[16];
+char g_dest[16];
+
+void reset_test_vars(void) {
+  memset(g_src, 0xff, sizeof(g_src));
+  memset(g_dest, 0, sizeof(g_dest));
+}
+
+#if defined(__x86_64__)
+# define MEM_SUFFIX "(%%r15)"
+#else
+# define MEM_SUFFIX
+#endif
+
+/*
+ * This test checks that non-temporal store instructions still have the
+ * same effect after being rewritten to normal store instructions.
+ */
+
+int main(void) {
+  /* Test movntdq. */
+  reset_test_vars();
+  asm("movdqa g_src " MEM_SUFFIX ", %%xmm0\n"
+      "movntdq %%xmm0, g_dest " MEM_SUFFIX "\n" : : : "xmm0");
+  ASSERT_EQ(memcmp(g_dest, g_src, 16), 0);
+
+#if defined(__i386__)
+  /* Test movntq. */
+  reset_test_vars();
+  asm("movq g_src, %%mm0\n"
+      "movntq %%mm0, g_dest\n" : : : "mm0");
+  ASSERT_EQ(memcmp(g_dest, g_src, 8), 0);
+#endif
+
+#if defined(__x86_64__)
+  /* Test movntps. */
+  reset_test_vars();
+  asm("movdqa g_src(%%r15), %%xmm0\n"
+      "movntps %%xmm0, g_dest(%%r15)\n" : : : "xmm0");
+  ASSERT_EQ(memcmp(g_dest, g_src, 16), 0);
+
+  /* Test movnti, using 32-bit operand. */
+  reset_test_vars();
+  asm("mov g_src(%%r15), %%eax\n"
+      "movnti %%eax, g_dest(%%r15)\n" : : : "eax");
+  ASSERT_EQ(memcmp(g_dest, g_src, 4), 0);
+
+  /* Test movnti, using 64-bit operand. */
+  reset_test_vars();
+  asm("mov g_src(%%r15), %%rax\n"
+      "movnti %%rax, g_dest(%%r15)\n" : : : "rax");
+  ASSERT_EQ(memcmp(g_dest, g_src, 8), 0);
+
+  /* Test movnti, using a destination with a restricted register. */
+  reset_test_vars();
+  asm("mov g_src(%%r15), %%rax\n"
+      ".p2align 5\n" /* Ensure following instructions are in the same bundle */
+      "leal g_dest, %%ecx\n"
+      "movnti %%rax, (%%r15, %%rcx)\n" : : : "rax", "rcx");
+  ASSERT_EQ(memcmp(g_dest, g_src, 4), 0);
+
+  /*
+   * Test movnti, using a destination with RIP-relative addressing,
+   * which is sensitive to the address of the instruction.
+   */
+  reset_test_vars();
+  asm("mov g_src(%%r15), %%rax\n"
+      "movnti %%rax, g_dest(%%rip)\n" : : : "rax");
+  ASSERT_EQ(memcmp(g_dest, g_src, 8), 0);
+
+  /* Test prefetchnta.  This has no side effects that we can test for. */
+  asm("prefetchnta g_dest(%r15)\n");
+#endif
+
+  return 0;
+}