Cleanup CPU detection and tuning for old CPUs.

1 files changed, 23 insertions, 42 deletions

diff --git a/src/lib_jit.c b/src/lib_jit.c
index c97b0d531..acd6c293b 100644
--- a/src/lib_jit.c
+++ b/src/lib_jit.c
@@ -104,8 +104,8 @@ LJLIB_CF(jit_status)
   jit_State *J = L2J(L);
   L->top = L->base;
   setboolV(L->top++, (J->flags & JIT_F_ON) ? 1 : 0);
-  flagbits_to_strings(L, J->flags, JIT_F_CPU_FIRST, JIT_F_CPUSTRING);
-  flagbits_to_strings(L, J->flags, JIT_F_OPT_FIRST, JIT_F_OPTSTRING);
+  flagbits_to_strings(L, J->flags, JIT_F_CPU, JIT_F_CPUSTRING);
+  flagbits_to_strings(L, J->flags, JIT_F_OPT, JIT_F_OPTSTRING);
   return (int)(L->top - L->base);
 #else
   setboolV(L->top++, 0);
@@ -471,7 +471,7 @@ static int jitopt_flag(jit_State *J, const char *str)
     str += str[2] == '-' ? 3 : 2;
     set = 0;
   }
-  for (opt = JIT_F_OPT_FIRST; ; opt <<= 1) {
+  for (opt = JIT_F_OPT; ; opt <<= 1) {
     size_t len = *(const uint8_t *)lst;
     if (len == 0)
       break;
@@ -640,59 +640,41 @@ JIT_PARAMDEF(JIT_PARAMINIT)
 #undef JIT_PARAMINIT
   0
 };
-#endif
 
 #if LJ_TARGET_ARM && LJ_TARGET_LINUX
 #include <sys/utsname.h>
 #endif
 
-/* Arch-dependent CPU detection. */
-static uint32_t jit_cpudetect(lua_State *L)
+/* Arch-dependent CPU feature detection. */
+static uint32_t jit_cpudetect(void)
 {
   uint32_t flags = 0;
 #if LJ_TARGET_X86ORX64
+
   uint32_t vendor[4];
   uint32_t features[4];
   if (lj_vm_cpuid(0, vendor) && lj_vm_cpuid(1, features)) {
-#if !LJ_HASJIT
-#define JIT_F_SSE2      2
-#endif
-    flags |= ((features[3] >> 26)&1) * JIT_F_SSE2;
-#if LJ_HASJIT
     flags |= ((features[2] >> 0)&1) * JIT_F_SSE3;
     flags |= ((features[2] >> 19)&1) * JIT_F_SSE4_1;
-    if (vendor[2] == 0x6c65746e) {  /* Intel. */
-      if ((features[0] & 0x0fff0ff0) == 0x000106c0)  /* Atom. */
-        flags |= JIT_F_LEA_AGU;
-    } else if (vendor[2] == 0x444d4163) {  /* AMD. */
-      uint32_t fam = (features[0] & 0x0ff00f00);
-      if (fam >= 0x00000f00)  /* K8, K10. */
-        flags |= JIT_F_PREFER_IMUL;
-    }
     if (vendor[0] >= 7) {
       uint32_t xfeatures[4];
       lj_vm_cpuid(7, xfeatures);
       flags |= ((xfeatures[1] >> 8)&1) * JIT_F_BMI2;
     }
-#endif
   }
-  /* Check for required instruction set support on x86 (unnecessary on x64). */
-#if LJ_TARGET_X86
-  if (!(flags & JIT_F_SSE2))
-    luaL_error(L, "CPU with SSE2 required");
-#endif
+  /* Don't bother checking for SSE2 -- the VM will crash before getting here. */
+
 #elif LJ_TARGET_ARM
-#if LJ_HASJIT
+
   int ver = LJ_ARCH_VERSION;  /* Compile-time ARM CPU detection. */
 #if LJ_TARGET_LINUX
   if (ver < 70) {  /* Runtime ARM CPU detection. */
     struct utsname ut;
     uname(&ut);
     if (strncmp(ut.machine, "armv", 4) == 0) {
-      if (ut.machine[4] >= '7')
-        ver = 70;
-      else if (ut.machine[4] == '6')
-        ver = 60;
+      if (ut.machine[4] >= '8') ver = 80;
+      else if (ut.machine[4] == '7') ver = 70;
+      else if (ut.machine[4] == '6') ver = 60;
     }
   }
 #endif
@@ -700,20 +682,22 @@ static uint32_t jit_cpudetect(lua_State *L)
            ver >= 61 ? JIT_F_ARMV6T2_ :
            ver >= 60 ? JIT_F_ARMV6_ : 0;
   flags |= LJ_ARCH_HASFPU == 0 ? 0 : ver >= 70 ? JIT_F_VFPV3 : JIT_F_VFPV2;
-#endif
+
 #elif LJ_TARGET_ARM64
+
   /* No optional CPU features to detect (for now). */
+
 #elif LJ_TARGET_PPC
-#if LJ_HASJIT
+
 #if LJ_ARCH_SQRT
   flags |= JIT_F_SQRT;
 #endif
 #if LJ_ARCH_ROUND
   flags |= JIT_F_ROUND;
 #endif
-#endif
+
 #elif LJ_TARGET_MIPS
-#if LJ_HASJIT
+
   /* Compile-time MIPS CPU detection. */
 #if LJ_ARCH_VERSION >= 20
   flags |= JIT_F_MIPSXXR2;
@@ -731,31 +715,28 @@ static uint32_t jit_cpudetect(lua_State *L)
     if (x) flags |= JIT_F_MIPSXXR2;  /* Either 0x80000000 (R2) or 0 (R1). */
   }
 #endif
-#endif
+
 #else
 #error "Missing CPU detection for this architecture"
 #endif
-  UNUSED(L);
   return flags;
 }
 
 /* Initialize JIT compiler. */
 static void jit_init(lua_State *L)
 {
-  uint32_t flags = jit_cpudetect(L);
-#if LJ_HASJIT
   jit_State *J = L2J(L);
-  J->flags = flags | JIT_F_ON | JIT_F_OPT_DEFAULT;
+  J->flags = jit_cpudetect() | JIT_F_ON | JIT_F_OPT_DEFAULT;
   memcpy(J->param, jit_param_default, sizeof(J->param));
   lj_dispatch_update(G(L));
-#else
-  UNUSED(flags);
-#endif
 }
+#endif
 
 LUALIB_API int luaopen_jit(lua_State *L)
 {
+#if LJ_HASJIT
   jit_init(L);
+#endif
   lua_pushliteral(L, LJ_OS_NAME);
   lua_pushliteral(L, LJ_ARCH_NAME);
   lua_pushinteger(L, LUAJIT_VERSION_NUM);