1 files changed, 206 insertions, 0 deletions
diff --git a/mozglue/build/SSE.cpp b/mozglue/build/SSE.cpp
new file mode 100644
index 000000000..8ad228684
--- /dev/null
+++ b/mozglue/build/SSE.cpp
@@ -0,0 +1,206 @@
+/* vim: set shiftwidth=4 tabstop=8 autoindent cindent expandtab: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* compile-time and runtime tests for whether to use SSE instructions */
+
+#include "SSE.h"
+
+#ifdef HAVE_CPUID_H
+// cpuid.h is available on gcc 4.3 and higher on i386 and x86_64
+#include <cpuid.h>
+#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64))
+// MSVC 2005 or newer on x86-32 or x86-64
+#include <intrin.h>
+#endif
+
+namespace {
+
+// SSE.h has parallel #ifs which declare MOZILLA_SSE_HAVE_CPUID_DETECTION.
+// We can't declare these functions in the header file, however, because
+// <intrin.h> conflicts with <windows.h> on MSVC 2005, and some files want to
+// include both SSE.h and <windows.h>.
+
+#ifdef HAVE_CPUID_H
+
+enum CPUIDRegister { eax = 0, ebx = 1, ecx = 2, edx = 3 };
+
+static bool
+has_cpuid_bits(unsigned int level, CPUIDRegister reg, unsigned int bits)
+{
+  unsigned int regs[4];
+  unsigned int eax, ebx, ecx, edx;
+  unsigned max = __get_cpuid_max(0, NULL);
+  if (level > max)
+    return false;
+  __cpuid_count(level, 0, eax, ebx, ecx, edx);
+  regs[0] = eax;
+  regs[1] = ebx;
+  regs[2] = ecx;
+  regs[3] = edx;
+  return (regs[reg] & bits) == bits;
+}
+
+#if !defined(MOZILLA_PRESUME_AVX)
+static uint64_t xgetbv(uint32_t xcr) {
+    uint32_t eax, edx;
+    __asm__ ( ".byte 0x0f, 0x01, 0xd0" : "=a"(eax), "=d"(edx) : "c"(xcr));
+    return (uint64_t)(edx) << 32 | eax;
+}
+#endif
+
+#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64))
+
+enum CPUIDRegister { eax = 0, ebx = 1, ecx = 2, edx = 3 };
+
+static bool
+has_cpuid_bits(unsigned int level, CPUIDRegister reg, unsigned int bits)
+{
+  // Check that the level in question is supported.
+  int regs[4];
+  __cpuid(regs, level & 0x80000000u);
+  if (unsigned(regs[0]) < level)
+    return false;
+
+  // "The __cpuid intrinsic clears the ECX register before calling the cpuid instruction."
+  __cpuid(regs, level);
+  return (unsigned(regs[reg]) & bits) == bits;
+}
+
+#if !defined(MOZILLA_PRESUME_AVX)
+static uint64_t xgetbv(uint32_t xcr) { return _xgetbv(xcr); }
+#endif
+
+#elif (defined(__GNUC__) || defined(__SUNPRO_CC)) && (defined(__i386) || defined(__x86_64__))
+
+enum CPUIDRegister { eax = 0, ebx = 1, ecx = 2, edx = 3 };
+
+#ifdef __i386
+static void
+moz_cpuid(int CPUInfo[4], int InfoType)
+{
+  asm (
+    "xchg %esi, %ebx\n"
+    "xor %ecx, %ecx\n" // ecx is the sub-leaf (we only ever need 0)
+    "cpuid\n"
+    "movl %eax, (%edi)\n"
+    "movl %ebx, 4(%edi)\n"
+    "movl %ecx, 8(%edi)\n"
+    "movl %edx, 12(%edi)\n"
+    "xchg %esi, %ebx\n"
+    :
+    : "a"(InfoType), // %eax
+      "D"(CPUInfo) // %edi
+    : "%ecx", "%edx", "%esi"
+  );
+}
+#else
+static void
+moz_cpuid(int CPUInfo[4], int InfoType)
+{
+  asm (
+    "xchg %rsi, %rbx\n"
+    "xor %ecx, %ecx\n" // ecx is the sub-leaf (we only ever need 0)
+    "cpuid\n"
+    "movl %eax, (%rdi)\n"
+    "movl %ebx, 4(%rdi)\n"
+    "movl %ecx, 8(%rdi)\n"
+    "movl %edx, 12(%rdi)\n"
+    "xchg %rsi, %rbx\n"
+    :
+    : "a"(InfoType), // %eax
+      "D"(CPUInfo) // %rdi
+    : "%ecx", "%edx", "%rsi"
+  );
+}
+#endif
+
+static bool
+has_cpuid_bits(unsigned int level, CPUIDRegister reg, unsigned int bits)
+{
+  // Check that the level in question is supported.
+  volatile int regs[4];
+  moz_cpuid((int *)regs, level & 0x80000000u);
+  if (unsigned(regs[0]) < level)
+    return false;
+
+  moz_cpuid((int *)regs, level);
+  return (unsigned(regs[reg]) & bits) == bits;
+}
+
+#endif // end CPUID declarations
+
+} // namespace
+
+namespace mozilla {
+
+namespace sse_private {
+
+#if defined(MOZILLA_SSE_HAVE_CPUID_DETECTION)
+
+#if !defined(MOZILLA_PRESUME_MMX)
+  bool mmx_enabled = has_cpuid_bits(1u, edx, (1u<<23));
+#endif
+
+#if !defined(MOZILLA_PRESUME_SSE)
+  bool sse_enabled = has_cpuid_bits(1u, edx, (1u<<25));
+#endif
+
+#if !defined(MOZILLA_PRESUME_SSE2)
+  bool sse2_enabled = has_cpuid_bits(1u, edx, (1u<<26));
+#endif
+
+#if !defined(MOZILLA_PRESUME_SSE3)
+  bool sse3_enabled = has_cpuid_bits(1u, ecx, (1u<<0));
+#endif
+
+#if !defined(MOZILLA_PRESUME_SSSE3)
+  bool ssse3_enabled = has_cpuid_bits(1u, ecx, (1u<<9));
+#endif
+
+#if !defined(MOZILLA_PRESUME_SSE4A)
+  bool sse4a_enabled = has_cpuid_bits(0x80000001u, ecx, (1u<<6));
+#endif
+
+#if !defined(MOZILLA_PRESUME_SSE4_1)
+  bool sse4_1_enabled = has_cpuid_bits(1u, ecx, (1u<<19));
+#endif
+
+#if !defined(MOZILLA_PRESUME_SSE4_2)
+  bool sse4_2_enabled = has_cpuid_bits(1u, ecx, (1u<<20));
+#endif
+
+#if !defined(MOZILLA_PRESUME_AVX) || !defined(MOZILLA_PRESUME_AVX2)
+  static bool has_avx()
+  {
+#if defined(MOZILLA_PRESUME_AVX)
+      return true;
+#else
+      const unsigned AVX = 1u << 28;
+      const unsigned OSXSAVE = 1u << 27;
+      const unsigned XSAVE = 1u << 26;
+
+      const unsigned XMM_STATE = 1u << 1;
+      const unsigned YMM_STATE = 1u << 2;
+      const unsigned AVX_STATE = XMM_STATE | YMM_STATE;
+
+      return has_cpuid_bits(1u, ecx, AVX | OSXSAVE | XSAVE) &&
+          // ensure the OS supports XSAVE of YMM registers
+          (xgetbv(0) & AVX_STATE) == AVX_STATE;
+#endif // MOZILLA_PRESUME_AVX
+  }
+#endif // !MOZILLA_PRESUME_AVX || !MOZILLA_PRESUME_AVX2
+
+#if !defined(MOZILLA_PRESUME_AVX)
+  bool avx_enabled = has_avx();
+#endif
+
+#if !defined(MOZILLA_PRESUME_AVX2)
+  bool avx2_enabled = has_avx() && has_cpuid_bits(7u, ebx, (1u<<5));
+#endif
+
+#endif
+
+} // namespace sse_private
+} // namespace mozilla