Cleanup JMP optimization pass

diff --git a/ext/opcache/Optimizer/pass3.c b/ext/opcache/Optimizer/pass3.c
index 6e406f112766b31d51c336233884bba5e496a010..de2acc6dbc9058cd411b0a244323a3063d702444 100644 (file)
--- a/ext/opcache/Optimizer/pass3.c
+++ b/ext/opcache/Optimizer/pass3.c
@@ -32,15 +32,24 @@
 #include "zend_vm.h"
 
 /* we use "jmp_hitlist" to avoid infinity loops during jmp optimization */
-#define CHECK_JMP(target, label)                                       \
-       do {                                                                                    \
-               for (i=0; i<jmp_hitlist_count; i++) {           \
-                       if (jmp_hitlist[i] == target) {                 \
-                               goto label;                                                     \
-                       }                                                                               \
-               }                                                                                       \
+static zend_always_inline int in_hitlist(zend_op *target, zend_op **jmp_hitlist, int jmp_hitlist_count)
+{
+       int i;
+
+       for (i = 0; i < jmp_hitlist_count; i++) {
+               if (jmp_hitlist[i] == target) {
+                       return 1;
+               }
+       }
+       return 0;
+}
+
+#define CHECK_LOOP(target) \
+       if (EXPECTED(!in_hitlist(target, jmp_hitlist, jmp_hitlist_count))) { \
                jmp_hitlist[jmp_hitlist_count++] = target;      \
-       } while (0)
+       } else { \
+               break; \
+       }
 
 void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
 {
@@ -49,7 +58,6 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
        zend_op *target;
        zend_op **jmp_hitlist;
        int jmp_hitlist_count;
-       int i;
        ALLOCA_FLAG(use_heap);
 
        jmp_hitlist = (zend_op**)do_alloca(sizeof(zend_op*)*op_array->last, use_heap);
@@ -64,10 +72,17 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
 
                                /* convert JMP L1 ... L1: JMP L2 to JMP L2 .. L1: JMP L2 */
                                target = ZEND_OP1_JMP_ADDR(opline);
-                               while (target->opcode == ZEND_JMP) {
-                                       target = ZEND_OP1_JMP_ADDR(target);
-                                       CHECK_JMP(target, done_jmp_optimization);
-                                       ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target);
+                               while (1) {
+                                       if (target->opcode == ZEND_JMP) {
+                                               target = ZEND_OP1_JMP_ADDR(target);
+                                               CHECK_LOOP(target);
+                                               ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target);
+                                       } else if (target->opcode == ZEND_JMP) {
+                                               target = target + 1;
+                                               ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target);
+                                       } else {
+                                               break;
+                                       }
                                }
 
                                /* convert L: JMP L+1 to NOP */
@@ -106,10 +121,17 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
                                jmp_hitlist_count = 0;
 
                                target = ZEND_OP2_JMP_ADDR(opline);
-                               while (target->opcode == ZEND_JMP) {
-                                       target = ZEND_OP1_JMP_ADDR(target);
-                                       CHECK_JMP(target, done_jmp_optimization);
-                                       ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
+                               while (1) {
+                                       if (target->opcode == ZEND_JMP) {
+                                               target = ZEND_OP1_JMP_ADDR(target);
+                                               CHECK_LOOP(target);
+                                               ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
+                                       } else if (target->opcode == ZEND_JMP) {
+                                               target = target + 1;
+                                               ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
+                                       } else {
+                                               break;
+                                       }
                                }
                                break;
 
@@ -123,14 +145,14 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
                                                /* plain JMP */
                                                /* JMPZ(X,L1), L1: JMP(L2) => JMPZ(X,L2), L1: JMP(L2) */
                                                target = ZEND_OP1_JMP_ADDR(target);
-                                               CHECK_JMP(target, done_jmp_optimization);
+                                               CHECK_LOOP(target);
                                                ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
                                        } else if (target->opcode == opline->opcode &&
                                                   SAME_VAR(opline->op1, target->op1)) {
                                                /* same opcode and same var as this opcode */
                                                /* JMPZ(X,L1), L1: JMPZ(X,L2) => JMPZ(X,L2), L1: JMPZ(X,L2) */
                                                target = ZEND_OP2_JMP_ADDR(target);
-                                               CHECK_JMP(target, done_jmp_optimization);
+                                               CHECK_LOOP(target);
                                                ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
                                        } else if (target->opcode == INV_COND(opline->opcode) &&
                                                   SAME_VAR(opline->op1, target->op1)) {
@@ -146,7 +168,10 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
                                                        /* JMPNZ_EX */
                                                        target = ZEND_OFFSET_TO_OPLINE(target, target->extended_value);
                                                }
-                                               CHECK_JMP(target, done_jmp_optimization);
+                                               CHECK_LOOP(target);
+                                               ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
+                                       } else if (target->opcode == ZEND_JMP) {
+                                               target = target + 1;
                                                ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
                                        } else {
                                                break;
@@ -177,7 +202,7 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
                                                /* plain JMP */
                                                /* JMPZ_EX(X,L1), L1: JMP(L2) => JMPZ_EX(X,L2), L1: JMP(L2) */
                                                target = ZEND_OP1_JMP_ADDR(target);
-                                               CHECK_JMP(target, done_jmp_optimization);
+                                               CHECK_LOOP(target);
                                                ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
                                        } else if (target->opcode == opline->opcode-3 &&
                                                   (SAME_VAR(target->op1, opline->result) ||
@@ -185,7 +210,7 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
                                                /* convert T=JMPZ_EX(X,L1), L1: JMPZ(T,L2) to
                                                   JMPZ_EX(X,L2) */
                                                target = ZEND_OP2_JMP_ADDR(target);
-                                               CHECK_JMP(target, done_jmp_optimization);
+                                               CHECK_LOOP(target);
                                                ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
                                        } else if (target->opcode == opline->opcode &&
                                                   (SAME_VAR(target->op1, opline->result) ||
@@ -194,7 +219,7 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
                                                /* convert T=JMPZ_EX(X,L1), L1: T=JMPZ_EX(T,L2) to
                                                   JMPZ_EX(X,L2) */
                                                target = ZEND_OP2_JMP_ADDR(target);
-                                               CHECK_JMP(target, done_jmp_optimization);
+                                               CHECK_LOOP(target);
                                                ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
                                        } else if (target->opcode == ZEND_JMPZNZ &&
                                                           SAME_VAR(target->op1, opline->result)) {
@@ -205,7 +230,7 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
                                                        /* JMPNZ_EX */
                                                        target = ZEND_OFFSET_TO_OPLINE(target, target->extended_value);
                                                }
-                                               CHECK_JMP(target, done_jmp_optimization);
+                                               CHECK_LOOP(target);
                                                ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
                                        } else if (target->opcode == INV_EX_COND(opline->opcode) &&
                                                   (SAME_VAR(target->op1, opline->result) ||
@@ -228,13 +253,25 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
                                                    SAME_VAR(target->op1, opline->op1))) {
                                                /* convert Y = JMPZ_EX(X,L1), L1: Z = BOOL(Y) to
                                                   Z = JMPZ_EX(X,L1+1) */
+
+                                               /* NOTE: This optimization pattern is not safe, but works, */
+                                               /*       because result of JMPZ_EX instruction             */
+                                               /*       is not used on the following path and             */
+                                               /*       should be used once on the branch path.           */
+                                               /*                                                         */
+                                               /*       The pattern works well only if jums processed in  */
+                                               /*       direct order, otherwise it breakes JMPZ_EX        */
+                                               /*       sequences too early.                              */
                                                opline->result.var = target->result.var;
                                                target = target + 1;
                                                ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
+                                       } else if (target->opcode == ZEND_JMP) {
+                                               target = target + 1;
+                                               ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
                                        } else {
                                                break;
                                        }
-                               } /* while */
+                               }
 
                                /* convert L: T = JMPZ_EX X,L+1 to T = BOOL(X) */
                                if (target == opline + 1) {
@@ -242,7 +279,6 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
                                        opline->op2.num = 0;
                                        break;
                                }
-
                                break;
 
                        case ZEND_JMPZNZ:
@@ -250,22 +286,34 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
 
                                /* JMPZNZ(X,L1,L2), L1: JMP(L3) => JMPZNZ(X,L3,L2), L1: JMP(L3) */
                                target = ZEND_OP2_JMP_ADDR(opline);
-                               while (target->opcode == ZEND_JMP) {
-                                       target = ZEND_OP1_JMP_ADDR(target);
-                                       CHECK_JMP(target, continue_jmpznz_optimization);
-                                       ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
+                               while (1) {
+                                       if (target->opcode == ZEND_JMP) {
+                                               target = ZEND_OP1_JMP_ADDR(target);
+                                               CHECK_LOOP(target);
+                                               ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
+                                       } else if (target->opcode == ZEND_JMP) {
+                                               target = target + 1;
+                                               ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
+                                       } else {
+                                               break;
+                                       }
                                }
-continue_jmpznz_optimization:
-                               /* JMPZNZ(X,L1,L2), L2: JMP(L3) => JMPZNZ(X,L1,L3), L2: JMP(L3) */
+
                                target = ZEND_OFFSET_TO_OPLINE(opline, opline->extended_value);
-                               while (target->opcode == ZEND_JMP) {
-                                       target = ZEND_OP1_JMP_ADDR(target);
-                                       CHECK_JMP(target, done_jmp_optimization);
-                                       opline->extended_value = ZEND_OPLINE_TO_OFFSET(opline, target);
+                               while (1) {
+                                       if (target->opcode == ZEND_JMP) {
+                                               target = ZEND_OP1_JMP_ADDR(target);
+                                               CHECK_LOOP(target);
+                                               opline->extended_value = ZEND_OPLINE_TO_OFFSET(opline, target);
+                                       } else if (target->opcode == ZEND_JMP) {
+                                               target = target + 1;
+                                               opline->extended_value = ZEND_OPLINE_TO_OFFSET(opline, target);
+                                       } else {
+                                               break;
+                                       }
                                }
                                break;
                }
-done_jmp_optimization:
                opline++;
        }
        free_alloca(jmp_hitlist, use_heap);