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sccp.c
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/*
+----------------------------------------------------------------------+
| Zend Engine, SCCP - Sparse Conditional Constant Propagation |
+----------------------------------------------------------------------+
| Copyright (c) The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 3.01 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
| available through the world-wide-web at the following url: |
| https://www.php.net/license/3_01.txt |
| If you did not receive a copy of the PHP license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| [email protected] so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Authors: Nikita Popov <[email protected]> |
| Dmitry Stogov <[email protected]> |
+----------------------------------------------------------------------+
*/
#include "zend_API.h"
#include "zend_exceptions.h"
#include "zend_ini.h"
#include "zend_type_info.h"
#include "Optimizer/zend_optimizer_internal.h"
#include "Optimizer/zend_call_graph.h"
#include "Optimizer/zend_inference.h"
#include "Optimizer/scdf.h"
#include "Optimizer/zend_dump.h"
/* This implements sparse conditional constant propagation (SCCP) based on the SCDF framework. The
* used value lattice is defined as follows:
*
* BOT < {constant values} < TOP
*
* TOP indicates an underdefined value, i.e. that we do not yet know the value of variable.
* BOT indicates an overdefined value, i.e. that we know the variable to be non-constant.
*
* All variables are optimistically initialized to TOP, apart from the implicit variables defined
* at the start of the first block. Note that variables that MAY_BE_REF are *not* initialized to
* BOT. We rely on the fact that any operation resulting in a reference will produce a BOT anyway.
* This is better because such operations might never be reached due to the conditional nature of
* the algorithm.
*
* The meet operation for phi functions is defined as follows:
* BOT + any = BOT
* TOP + any = any
* C_i + C_i = C_i (i.e. two equal constants)
* C_i + C_j = BOT (i.e. two different constants)
*
* When evaluating instructions TOP and BOT are handled as follows:
* a) If any operand is BOT, the result is BOT. The main exception to this is op1 of ASSIGN, which
* is ignored. However, if the op1 MAY_BE_REF we do have to propagate the BOT.
* b) Otherwise, if the instruction can never be evaluated (either in general, or with the
* specific modifiers) the result is BOT.
* c) Otherwise, if any operand is TOP, the result is TOP.
* d) Otherwise (at this point all operands are known and constant), if we can compute the result
* for these specific constants (without throwing notices or similar) then that is the result.
* e) Otherwise the result is BOT.
*
* It is sometimes possible to determine a result even if one argument is TOP / BOT, e.g. for things
* like BOT*0. Right now we don't bother with this.
*
* Feasible successors for conditional branches are determined as follows:
* a) If we don't support the branch type or branch on BOT, all successors are feasible.
* b) Otherwise, if we branch on TOP none of the successors are feasible.
* c) Otherwise (we branch on a constant), the feasible successors are marked based on the constant
* (usually only one successor will be feasible).
*
* The original SCCP algorithm is extended with ability to propagate constant array
* elements and object properties. The extension is based on a variation of Array
* SSA form and its application to Spare Constant Propagation, described at
* "Array SSA Form" by Vivek Sarkar, Kathleen Knobe and Stephen Fink in chapter
* 16 of the SSA book.
*/
#define SCP_DEBUG 0
typedef struct _sccp_ctx {
scdf_ctx scdf;
zend_call_info **call_map;
zval *values;
zval top;
zval bot;
} sccp_ctx;
#define TOP ((zend_uchar)-1)
#define BOT ((zend_uchar)-2)
#define PARTIAL_ARRAY ((zend_uchar)-3)
#define PARTIAL_OBJECT ((zend_uchar)-4)
#define IS_TOP(zv) (Z_TYPE_P(zv) == TOP)
#define IS_BOT(zv) (Z_TYPE_P(zv) == BOT)
#define IS_PARTIAL_ARRAY(zv) (Z_TYPE_P(zv) == PARTIAL_ARRAY)
#define IS_PARTIAL_OBJECT(zv) (Z_TYPE_P(zv) == PARTIAL_OBJECT)
#define MAKE_PARTIAL_ARRAY(zv) (Z_TYPE_INFO_P(zv) = PARTIAL_ARRAY | (IS_TYPE_REFCOUNTED << Z_TYPE_FLAGS_SHIFT))
#define MAKE_PARTIAL_OBJECT(zv) (Z_TYPE_INFO_P(zv) = PARTIAL_OBJECT | (IS_TYPE_REFCOUNTED << Z_TYPE_FLAGS_SHIFT))
#define MAKE_TOP(zv) (Z_TYPE_INFO_P(zv) = TOP)
#define MAKE_BOT(zv) (Z_TYPE_INFO_P(zv) = BOT)
static void scp_dump_value(zval *zv) {
if (IS_TOP(zv)) {
fprintf(stderr, " top");
} else if (IS_BOT(zv)) {
fprintf(stderr, " bot");
} else if (Z_TYPE_P(zv) == IS_ARRAY || IS_PARTIAL_ARRAY(zv)) {
fprintf(stderr, " %s[", IS_PARTIAL_ARRAY(zv) ? "partial " : "");
zend_dump_ht(Z_ARRVAL_P(zv));
fprintf(stderr, "]");
} else if (IS_PARTIAL_OBJECT(zv)) {
fprintf(stderr, " {");
zend_dump_ht(Z_ARRVAL_P(zv));
fprintf(stderr, "}");
} else {
zend_dump_const(zv);
}
}
static void empty_partial_array(zval *zv)
{
MAKE_PARTIAL_ARRAY(zv);
Z_ARR_P(zv) = zend_new_array(8);
}
static void dup_partial_array(zval *dst, zval *src)
{
MAKE_PARTIAL_ARRAY(dst);
Z_ARR_P(dst) = zend_array_dup(Z_ARR_P(src));
}
static void empty_partial_object(zval *zv)
{
MAKE_PARTIAL_OBJECT(zv);
Z_ARR_P(zv) = zend_new_array(8);
}
static void dup_partial_object(zval *dst, zval *src)
{
MAKE_PARTIAL_OBJECT(dst);
Z_ARR_P(dst) = zend_array_dup(Z_ARR_P(src));
}
static inline bool value_known(zval *zv) {
return !IS_TOP(zv) && !IS_BOT(zv);
}
/* Sets new value for variable and ensures that it is lower or equal
* the previous one in the constant propagation lattice. */
static void set_value(scdf_ctx *scdf, sccp_ctx *ctx, int var, zval *new) {
zval *value = &ctx->values[var];
if (IS_BOT(value) || IS_TOP(new)) {
return;
}
#if SCP_DEBUG
fprintf(stderr, "Lowering #%d.", var);
zend_dump_var(scdf->op_array, IS_CV, scdf->ssa->vars[var].var);
fprintf(stderr, " from");
scp_dump_value(value);
fprintf(stderr, " to");
scp_dump_value(new);
fprintf(stderr, "\n");
#endif
if (IS_TOP(value) || IS_BOT(new)) {
zval_ptr_dtor_nogc(value);
ZVAL_COPY(value, new);
scdf_add_to_worklist(scdf, var);
return;
}
/* Always replace PARTIAL_(ARRAY|OBJECT), as new maybe changed by join_partial_(arrays|object) */
if (IS_PARTIAL_ARRAY(new) || IS_PARTIAL_OBJECT(new)) {
if (Z_TYPE_P(value) != Z_TYPE_P(new)
|| zend_hash_num_elements(Z_ARR_P(new)) != zend_hash_num_elements(Z_ARR_P(value))) {
zval_ptr_dtor_nogc(value);
ZVAL_COPY(value, new);
scdf_add_to_worklist(scdf, var);
}
return;
}
#if ZEND_DEBUG
ZEND_ASSERT(zend_is_identical(value, new));
#endif
}
static zval *get_op1_value(sccp_ctx *ctx, zend_op *opline, zend_ssa_op *ssa_op) {
if (opline->op1_type == IS_CONST) {
return CT_CONSTANT_EX(ctx->scdf.op_array, opline->op1.constant);
} else if (ssa_op->op1_use != -1) {
return &ctx->values[ssa_op->op1_use];
} else {
return NULL;
}
}
static zval *get_op2_value(sccp_ctx *ctx, zend_op *opline, zend_ssa_op *ssa_op) {
if (opline->op2_type == IS_CONST) {
return CT_CONSTANT_EX(ctx->scdf.op_array, opline->op2.constant);
} else if (ssa_op->op2_use != -1) {
return &ctx->values[ssa_op->op2_use];
} else {
return NULL;
}
}
static bool can_replace_op1(
const zend_op_array *op_array, zend_op *opline, zend_ssa_op *ssa_op) {
switch (opline->opcode) {
case ZEND_PRE_INC:
case ZEND_PRE_DEC:
case ZEND_PRE_INC_OBJ:
case ZEND_PRE_DEC_OBJ:
case ZEND_POST_INC:
case ZEND_POST_DEC:
case ZEND_POST_INC_OBJ:
case ZEND_POST_DEC_OBJ:
case ZEND_ASSIGN:
case ZEND_ASSIGN_REF:
case ZEND_ASSIGN_DIM:
case ZEND_ASSIGN_OBJ:
case ZEND_ASSIGN_OBJ_REF:
case ZEND_ASSIGN_OP:
case ZEND_ASSIGN_DIM_OP:
case ZEND_ASSIGN_OBJ_OP:
case ZEND_ASSIGN_STATIC_PROP_OP:
case ZEND_FETCH_DIM_W:
case ZEND_FETCH_DIM_RW:
case ZEND_FETCH_DIM_UNSET:
case ZEND_FETCH_DIM_FUNC_ARG:
case ZEND_FETCH_OBJ_W:
case ZEND_FETCH_OBJ_RW:
case ZEND_FETCH_OBJ_UNSET:
case ZEND_FETCH_OBJ_FUNC_ARG:
case ZEND_FETCH_LIST_W:
case ZEND_UNSET_DIM:
case ZEND_UNSET_OBJ:
case ZEND_SEND_REF:
case ZEND_SEND_VAR_EX:
case ZEND_SEND_FUNC_ARG:
case ZEND_SEND_UNPACK:
case ZEND_SEND_ARRAY:
case ZEND_SEND_USER:
case ZEND_FE_RESET_RW:
return 0;
/* Do not accept CONST */
case ZEND_ROPE_ADD:
case ZEND_ROPE_END:
case ZEND_BIND_STATIC:
case ZEND_BIND_GLOBAL:
case ZEND_MAKE_REF:
case ZEND_UNSET_CV:
case ZEND_ISSET_ISEMPTY_CV:
return 0;
case ZEND_INIT_ARRAY:
case ZEND_ADD_ARRAY_ELEMENT:
return !(opline->extended_value & ZEND_ARRAY_ELEMENT_REF);
case ZEND_YIELD:
return !(op_array->fn_flags & ZEND_ACC_RETURN_REFERENCE);
case ZEND_VERIFY_RETURN_TYPE:
// TODO: This would require a non-local change ???
return 0;
case ZEND_OP_DATA:
return (opline - 1)->opcode != ZEND_ASSIGN_OBJ_REF &&
(opline - 1)->opcode != ZEND_ASSIGN_STATIC_PROP_REF;
default:
if (ssa_op->op1_def != -1) {
ZEND_UNREACHABLE();
return 0;
}
}
return 1;
}
static bool can_replace_op2(
const zend_op_array *op_array, zend_op *opline, zend_ssa_op *ssa_op) {
switch (opline->opcode) {
/* Do not accept CONST */
case ZEND_DECLARE_CLASS_DELAYED:
case ZEND_BIND_LEXICAL:
case ZEND_FE_FETCH_R:
case ZEND_FE_FETCH_RW:
return 0;
}
return 1;
}
static bool try_replace_op1(
sccp_ctx *ctx, zend_op *opline, zend_ssa_op *ssa_op, int var, zval *value) {
if (ssa_op->op1_use == var && can_replace_op1(ctx->scdf.op_array, opline, ssa_op)) {
zval zv;
ZVAL_COPY(&zv, value);
if (zend_optimizer_update_op1_const(ctx->scdf.op_array, opline, &zv)) {
return 1;
} else {
// TODO: check the following special cases ???
switch (opline->opcode) {
case ZEND_CASE:
opline->opcode = ZEND_IS_EQUAL;
goto replace_op1_simple;
case ZEND_CASE_STRICT:
opline->opcode = ZEND_IS_IDENTICAL;
goto replace_op1_simple;
case ZEND_FETCH_LIST_R:
case ZEND_SWITCH_STRING:
case ZEND_SWITCH_LONG:
case ZEND_MATCH:
replace_op1_simple:
if (Z_TYPE(zv) == IS_STRING) {
zend_string_hash_val(Z_STR(zv));
}
opline->op1.constant = zend_optimizer_add_literal(ctx->scdf.op_array, &zv);
opline->op1_type = IS_CONST;
return 1;
case ZEND_INSTANCEOF:
zval_ptr_dtor_nogc(&zv);
ZVAL_FALSE(&zv);
opline->opcode = ZEND_QM_ASSIGN;
opline->op1_type = IS_CONST;
opline->op1.constant = zend_optimizer_add_literal(ctx->scdf.op_array, &zv);
opline->op2_type = IS_UNUSED;
if (ssa_op->op2_use >= 0) {
ZEND_ASSERT(ssa_op->op2_def == -1);
zend_ssa_unlink_use_chain(ctx->scdf.ssa, ssa_op - ctx->scdf.ssa->ops, ssa_op->op2_use);
ssa_op->op2_use = -1;
ssa_op->op2_use_chain = -1;
}
return 1;
default:
break;
}
zval_ptr_dtor_nogc(&zv);
}
}
return 0;
}
static bool try_replace_op2(
sccp_ctx *ctx, zend_op *opline, zend_ssa_op *ssa_op, int var, zval *value) {
if (ssa_op->op2_use == var && can_replace_op2(ctx->scdf.op_array, opline, ssa_op)) {
zval zv;
ZVAL_COPY(&zv, value);
if (zend_optimizer_update_op2_const(ctx->scdf.op_array, opline, &zv)) {
return 1;
} else {
switch (opline->opcode) {
case ZEND_FETCH_CLASS:
if (Z_TYPE(zv) == IS_STRING) {
ZEND_ASSERT((opline + 1)->opcode == ZEND_INSTANCEOF);
ZEND_ASSERT(ssa_op->result_def == (ssa_op + 1)->op2_use);
if (zend_optimizer_update_op2_const(ctx->scdf.op_array, opline + 1, &zv)) {
zend_ssa_op *next_op = ssa_op + 1;
zend_ssa_unlink_use_chain(ctx->scdf.ssa, next_op - ctx->scdf.ssa->ops, next_op->op2_use);
next_op->op2_use = -1;
next_op->op2_use_chain = -1;
zend_ssa_remove_result_def(ctx->scdf.ssa, ssa_op);
MAKE_NOP(opline);
return 1;
}
}
default:
break;
}
zval_ptr_dtor_nogc(&zv);
}
}
return 0;
}
static inline zend_result ct_eval_binary_op(zval *result, zend_uchar binop, zval *op1, zval *op2) {
/* TODO: We could implement support for evaluation of + on partial arrays. */
if (IS_PARTIAL_ARRAY(op1) || IS_PARTIAL_ARRAY(op2)) {
return FAILURE;
}
return zend_optimizer_eval_binary_op(result, binop, op1, op2);
}
static inline zend_result ct_eval_bool_cast(zval *result, zval *op) {
if (IS_PARTIAL_ARRAY(op)) {
if (zend_hash_num_elements(Z_ARRVAL_P(op)) == 0) {
/* An empty partial array may be non-empty at runtime, we don't know whether the
* result will be true or false. */
return FAILURE;
}
ZVAL_TRUE(result);
return SUCCESS;
}
ZVAL_BOOL(result, zend_is_true(op));
return SUCCESS;
}
static inline zend_result zval_to_string_offset(zend_long *result, zval *op) {
switch (Z_TYPE_P(op)) {
case IS_LONG:
*result = Z_LVAL_P(op);
return SUCCESS;
case IS_STRING:
if (IS_LONG == is_numeric_string(
Z_STRVAL_P(op), Z_STRLEN_P(op), result, NULL, 0)) {
return SUCCESS;
}
return FAILURE;
default:
return FAILURE;
}
}
static inline zend_result fetch_array_elem(zval **result, zval *op1, zval *op2) {
switch (Z_TYPE_P(op2)) {
case IS_NULL:
*result = zend_hash_find(Z_ARR_P(op1), ZSTR_EMPTY_ALLOC());
return SUCCESS;
case IS_FALSE:
*result = zend_hash_index_find(Z_ARR_P(op1), 0);
return SUCCESS;
case IS_TRUE:
*result = zend_hash_index_find(Z_ARR_P(op1), 1);
return SUCCESS;
case IS_LONG:
*result = zend_hash_index_find(Z_ARR_P(op1), Z_LVAL_P(op2));
return SUCCESS;
case IS_DOUBLE: {
zend_long lval = zend_dval_to_lval(Z_DVAL_P(op2));
if (!zend_is_long_compatible(Z_DVAL_P(op2), lval)) {
return FAILURE;
}
*result = zend_hash_index_find(Z_ARR_P(op1), lval);
return SUCCESS;
}
case IS_STRING:
*result = zend_symtable_find(Z_ARR_P(op1), Z_STR_P(op2));
return SUCCESS;
default:
return FAILURE;
}
}
static inline zend_result ct_eval_fetch_dim(zval *result, zval *op1, zval *op2, int support_strings) {
if (Z_TYPE_P(op1) == IS_ARRAY || IS_PARTIAL_ARRAY(op1)) {
zval *value;
if (fetch_array_elem(&value, op1, op2) == SUCCESS && value && !IS_BOT(value)) {
ZVAL_COPY(result, value);
return SUCCESS;
}
} else if (support_strings && Z_TYPE_P(op1) == IS_STRING) {
zend_long index;
if (zval_to_string_offset(&index, op2) == FAILURE) {
return FAILURE;
}
if (index >= 0 && index < Z_STRLEN_P(op1)) {
ZVAL_STR(result, zend_string_init(&Z_STRVAL_P(op1)[index], 1, 0));
return SUCCESS;
}
}
return FAILURE;
}
/* op1 may be NULL here to indicate an unset value */
static inline zend_result ct_eval_isset_isempty(zval *result, uint32_t extended_value, zval *op1) {
zval zv;
if (!(extended_value & ZEND_ISEMPTY)) {
ZVAL_BOOL(result, op1 && Z_TYPE_P(op1) != IS_NULL);
return SUCCESS;
} else if (!op1) {
ZVAL_TRUE(result);
return SUCCESS;
} else if (ct_eval_bool_cast(&zv, op1) == SUCCESS) {
ZVAL_BOOL(result, Z_TYPE(zv) == IS_FALSE);
return SUCCESS;
} else {
return FAILURE;
}
}
static inline zend_result ct_eval_isset_dim(zval *result, uint32_t extended_value, zval *op1, zval *op2) {
if (Z_TYPE_P(op1) == IS_ARRAY || IS_PARTIAL_ARRAY(op1)) {
zval *value;
if (fetch_array_elem(&value, op1, op2) == FAILURE) {
return FAILURE;
}
if (IS_PARTIAL_ARRAY(op1) && (!value || IS_BOT(value))) {
return FAILURE;
}
return ct_eval_isset_isempty(result, extended_value, value);
} else if (Z_TYPE_P(op1) == IS_STRING) {
// TODO
return FAILURE;
} else {
ZVAL_BOOL(result, (extended_value & ZEND_ISEMPTY));
return SUCCESS;
}
}
static inline zend_result ct_eval_del_array_elem(zval *result, zval *key) {
ZEND_ASSERT(IS_PARTIAL_ARRAY(result));
switch (Z_TYPE_P(key)) {
case IS_NULL:
zend_hash_del(Z_ARR_P(result), ZSTR_EMPTY_ALLOC());
break;
case IS_FALSE:
zend_hash_index_del(Z_ARR_P(result), 0);
break;
case IS_TRUE:
zend_hash_index_del(Z_ARR_P(result), 1);
break;
case IS_LONG:
zend_hash_index_del(Z_ARR_P(result), Z_LVAL_P(key));
break;
case IS_DOUBLE: {
zend_long lval = zend_dval_to_lval(Z_DVAL_P(key));
if (!zend_is_long_compatible(Z_DVAL_P(key), lval)) {
return FAILURE;
}
zend_hash_index_del(Z_ARR_P(result), lval);
break;
}
case IS_STRING:
zend_symtable_del(Z_ARR_P(result), Z_STR_P(key));
break;
default:
return FAILURE;
}
return SUCCESS;
}
static inline zend_result ct_eval_add_array_elem(zval *result, zval *value, zval *key) {
if (!key) {
SEPARATE_ARRAY(result);
if ((value = zend_hash_next_index_insert(Z_ARR_P(result), value))) {
Z_TRY_ADDREF_P(value);
return SUCCESS;
}
return FAILURE;
}
switch (Z_TYPE_P(key)) {
case IS_NULL:
SEPARATE_ARRAY(result);
value = zend_hash_update(Z_ARR_P(result), ZSTR_EMPTY_ALLOC(), value);
break;
case IS_FALSE:
SEPARATE_ARRAY(result);
value = zend_hash_index_update(Z_ARR_P(result), 0, value);
break;
case IS_TRUE:
SEPARATE_ARRAY(result);
value = zend_hash_index_update(Z_ARR_P(result), 1, value);
break;
case IS_LONG:
SEPARATE_ARRAY(result);
value = zend_hash_index_update(Z_ARR_P(result), Z_LVAL_P(key), value);
break;
case IS_DOUBLE: {
zend_long lval = zend_dval_to_lval(Z_DVAL_P(key));
if (!zend_is_long_compatible(Z_DVAL_P(key), lval)) {
return FAILURE;
}
SEPARATE_ARRAY(result);
value = zend_hash_index_update(
Z_ARR_P(result), lval, value);
break;
}
case IS_STRING:
SEPARATE_ARRAY(result);
value = zend_symtable_update(Z_ARR_P(result), Z_STR_P(key), value);
break;
default:
return FAILURE;
}
Z_TRY_ADDREF_P(value);
return SUCCESS;
}
static inline zend_result ct_eval_add_array_unpack(zval *result, zval *array) {
zend_string *key;
zval *value;
if (Z_TYPE_P(array) != IS_ARRAY) {
return FAILURE;
}
SEPARATE_ARRAY(result);
ZEND_HASH_FOREACH_STR_KEY_VAL(Z_ARRVAL_P(array), key, value) {
if (key) {
value = zend_hash_update(Z_ARR_P(result), key, value);
} else {
value = zend_hash_next_index_insert(Z_ARR_P(result), value);
}
if (!value) {
return FAILURE;
}
Z_TRY_ADDREF_P(value);
} ZEND_HASH_FOREACH_END();
return SUCCESS;
}
static inline zend_result ct_eval_assign_dim(zval *result, zval *value, zval *key) {
switch (Z_TYPE_P(result)) {
case IS_NULL:
case IS_FALSE:
array_init(result);
ZEND_FALLTHROUGH;
case IS_ARRAY:
case PARTIAL_ARRAY:
return ct_eval_add_array_elem(result, value, key);
case IS_STRING:
// TODO Before enabling this case, make sure ARRAY_DIM result op is correct
#if 0
zend_long index;
zend_string *new_str, *value_str;
if (!key || Z_TYPE_P(value) == IS_ARRAY
|| zval_to_string_offset(&index, key) == FAILURE || index < 0) {
return FAILURE;
}
if (index >= Z_STRLEN_P(result)) {
new_str = zend_string_alloc(index + 1, 0);
memcpy(ZSTR_VAL(new_str), Z_STRVAL_P(result), Z_STRLEN_P(result));
memset(ZSTR_VAL(new_str) + Z_STRLEN_P(result), ' ', index - Z_STRLEN_P(result));
ZSTR_VAL(new_str)[index + 1] = 0;
} else {
new_str = zend_string_init(Z_STRVAL_P(result), Z_STRLEN_P(result), 0);
}
value_str = zval_get_string(value);
ZVAL_STR(result, new_str);
Z_STRVAL_P(result)[index] = ZSTR_VAL(value_str)[0];
zend_string_release_ex(value_str, 0);
#endif
return FAILURE;
default:
return FAILURE;
}
}
static inline zend_result fetch_obj_prop(zval **result, zval *op1, zval *op2) {
switch (Z_TYPE_P(op2)) {
case IS_STRING:
*result = zend_symtable_find(Z_ARR_P(op1), Z_STR_P(op2));
return SUCCESS;
default:
return FAILURE;
}
}
static inline zend_result ct_eval_fetch_obj(zval *result, zval *op1, zval *op2) {
if (IS_PARTIAL_OBJECT(op1)) {
zval *value;
if (fetch_obj_prop(&value, op1, op2) == SUCCESS && value && !IS_BOT(value)) {
ZVAL_COPY(result, value);
return SUCCESS;
}
}
return FAILURE;
}
static inline zend_result ct_eval_isset_obj(zval *result, uint32_t extended_value, zval *op1, zval *op2) {
if (IS_PARTIAL_OBJECT(op1)) {
zval *value;
if (fetch_obj_prop(&value, op1, op2) == FAILURE) {
return FAILURE;
}
if (!value || IS_BOT(value)) {
return FAILURE;
}
return ct_eval_isset_isempty(result, extended_value, value);
} else {
ZVAL_BOOL(result, (extended_value & ZEND_ISEMPTY));
return SUCCESS;
}
}
static inline zend_result ct_eval_del_obj_prop(zval *result, zval *key) {
ZEND_ASSERT(IS_PARTIAL_OBJECT(result));
switch (Z_TYPE_P(key)) {
case IS_STRING:
zend_symtable_del(Z_ARR_P(result), Z_STR_P(key));
break;
default:
return FAILURE;
}
return SUCCESS;
}
static inline zend_result ct_eval_add_obj_prop(zval *result, zval *value, zval *key) {
switch (Z_TYPE_P(key)) {
case IS_STRING:
value = zend_symtable_update(Z_ARR_P(result), Z_STR_P(key), value);
break;
default:
return FAILURE;
}
Z_TRY_ADDREF_P(value);
return SUCCESS;
}
static inline zend_result ct_eval_assign_obj(zval *result, zval *value, zval *key) {
switch (Z_TYPE_P(result)) {
case IS_NULL:
case IS_FALSE:
empty_partial_object(result);
ZEND_FALLTHROUGH;
case PARTIAL_OBJECT:
return ct_eval_add_obj_prop(result, value, key);
default:
return FAILURE;
}
}
static inline zend_result ct_eval_incdec(zval *result, zend_uchar opcode, zval *op1) {
if (Z_TYPE_P(op1) == IS_ARRAY || IS_PARTIAL_ARRAY(op1)) {
return FAILURE;
}
ZVAL_COPY(result, op1);
if (opcode == ZEND_PRE_INC
|| opcode == ZEND_POST_INC
|| opcode == ZEND_PRE_INC_OBJ
|| opcode == ZEND_POST_INC_OBJ) {
increment_function(result);
} else {
decrement_function(result);
}
return SUCCESS;
}
static inline void ct_eval_type_check(zval *result, uint32_t type_mask, zval *op1) {
uint32_t type = Z_TYPE_P(op1);
if (type == PARTIAL_ARRAY) {
type = IS_ARRAY;
} else if (type == PARTIAL_OBJECT) {
type = IS_OBJECT;
}
ZVAL_BOOL(result, (type_mask >> type) & 1);
}
static inline zend_result ct_eval_in_array(zval *result, uint32_t extended_value, zval *op1, zval *op2) {
HashTable *ht;
bool res;
if (Z_TYPE_P(op2) != IS_ARRAY) {
return FAILURE;
}
ht = Z_ARRVAL_P(op2);
if (EXPECTED(Z_TYPE_P(op1) == IS_STRING)) {
res = zend_hash_exists(ht, Z_STR_P(op1));
} else if (extended_value) {
if (EXPECTED(Z_TYPE_P(op1) == IS_LONG)) {
res = zend_hash_index_exists(ht, Z_LVAL_P(op1));
} else {
res = 0;
}
} else if (Z_TYPE_P(op1) <= IS_FALSE) {
res = zend_hash_exists(ht, ZSTR_EMPTY_ALLOC());
} else {
zend_string *key;
zval key_tmp;
res = 0;
ZEND_HASH_MAP_FOREACH_STR_KEY(ht, key) {
ZVAL_STR(&key_tmp, key);
if (zend_compare(op1, &key_tmp) == 0) {
res = 1;
break;
}
} ZEND_HASH_FOREACH_END();
}
ZVAL_BOOL(result, res);
return SUCCESS;
}
static inline zend_result ct_eval_array_key_exists(zval *result, zval *op1, zval *op2) {
zval *value;
if (Z_TYPE_P(op2) != IS_ARRAY && !IS_PARTIAL_ARRAY(op2)) {
return FAILURE;
}
if (Z_TYPE_P(op1) != IS_STRING && Z_TYPE_P(op1) != IS_LONG && Z_TYPE_P(op1) != IS_NULL) {
return FAILURE;
}
if (fetch_array_elem(&value, op2, op1) == FAILURE) {
return FAILURE;
}
if (IS_PARTIAL_ARRAY(op2) && (!value || IS_BOT(value))) {
return FAILURE;
}
ZVAL_BOOL(result, value != NULL);
return SUCCESS;
}
static bool can_ct_eval_func_call(zend_string *name, uint32_t num_args, zval **args) {
/* Functions in this list must always produce the same result for the same arguments,
* and have no dependence on global state (such as locales). It is okay if they throw
* or warn on invalid arguments, as we detect this and will discard the evaluation result. */
if (false
|| zend_string_equals_literal(name, "array_diff")
|| zend_string_equals_literal(name, "array_diff_assoc")
|| zend_string_equals_literal(name, "array_diff_key")
|| zend_string_equals_literal(name, "array_flip")
|| zend_string_equals_literal(name, "array_is_list")
|| zend_string_equals_literal(name, "array_key_exists")
|| zend_string_equals_literal(name, "array_keys")
|| zend_string_equals_literal(name, "array_merge")
|| zend_string_equals_literal(name, "array_merge_recursive")
|| zend_string_equals_literal(name, "array_replace")
|| zend_string_equals_literal(name, "array_replace_recursive")
|| zend_string_equals_literal(name, "array_unique")
|| zend_string_equals_literal(name, "array_values")
|| zend_string_equals_literal(name, "base64_decode")
|| zend_string_equals_literal(name, "base64_encode")
#ifndef ZEND_WIN32
/* On Windows this function may be code page dependent. */
|| zend_string_equals_literal(name, "dirname")
#endif
|| zend_string_equals_literal(name, "explode")
|| zend_string_equals_literal(name, "imagetypes")
|| zend_string_equals_literal(name, "in_array")
|| zend_string_equals_literal(name, "implode")
|| zend_string_equals_literal(name, "ltrim")
|| zend_string_equals_literal(name, "php_sapi_name")
|| zend_string_equals_literal(name, "php_uname")
|| zend_string_equals_literal(name, "phpversion")
|| zend_string_equals_literal(name, "pow")
|| zend_string_equals_literal(name, "preg_quote")
|| zend_string_equals_literal(name, "rawurldecode")
|| zend_string_equals_literal(name, "rawurlencode")
|| zend_string_equals_literal(name, "rtrim")
|| zend_string_equals_literal(name, "serialize")
|| zend_string_equals_literal(name, "str_contains")
|| zend_string_equals_literal(name, "str_ends_with")
|| zend_string_equals_literal(name, "str_replace")
|| zend_string_equals_literal(name, "str_split")
|| zend_string_equals_literal(name, "str_starts_with")
|| zend_string_equals_literal(name, "strpos")
|| zend_string_equals_literal(name, "strstr")
|| zend_string_equals_literal(name, "substr")
|| zend_string_equals_literal(name, "trim")
|| zend_string_equals_literal(name, "urldecode")
|| zend_string_equals_literal(name, "urlencode")
|| zend_string_equals_literal(name, "version_compare")
) {
return true;
}
if (num_args == 2) {
if (zend_string_equals_literal(name, "str_repeat")) {
/* Avoid creating overly large strings at compile-time. */
bool overflow;
return Z_TYPE_P(args[0]) == IS_STRING
&& Z_TYPE_P(args[1]) == IS_LONG
&& zend_safe_address(Z_STRLEN_P(args[0]), Z_LVAL_P(args[1]), 0, &overflow) < 64 * 1024
&& !overflow;
}
return false;
}
return false;
}
/* The functions chosen here are simple to implement and either likely to affect a branch,
* or just happened to be commonly used with constant operands in WP (need to test other
* applications as well, of course). */
static inline zend_result ct_eval_func_call(
zend_op_array *op_array, zval *result, zend_string *name, uint32_t num_args, zval **args) {
uint32_t i;
zend_function *func = zend_hash_find_ptr(CG(function_table), name);
if (!func || func->type != ZEND_INTERNAL_FUNCTION) {
return FAILURE;
}
if (num_args == 1) {
/* Handle a few functions for which we manually implement evaluation here. */
if (zend_string_equals_literal(name, "chr")) {
zend_long c;
if (Z_TYPE_P(args[0]) != IS_LONG) {
return FAILURE;
}
c = Z_LVAL_P(args[0]) & 0xff;
ZVAL_CHAR(result, c);
return SUCCESS;
} else if (zend_string_equals_literal(name, "count")) {
if (Z_TYPE_P(args[0]) != IS_ARRAY) {
return FAILURE;
}
ZVAL_LONG(result, zend_hash_num_elements(Z_ARRVAL_P(args[0])));
return SUCCESS;
} else if (zend_string_equals_literal(name, "ini_get")) {
zend_ini_entry *ini_entry;
if (Z_TYPE_P(args[0]) != IS_STRING) {
return FAILURE;
}
ini_entry = zend_hash_find_ptr(EG(ini_directives), Z_STR_P(args[0]));
if (!ini_entry) {
ZVAL_FALSE(result);
} else if (ini_entry->modifiable != ZEND_INI_SYSTEM) {
return FAILURE;
} else if (ini_entry->value) {
ZVAL_STR_COPY(result, ini_entry->value);
} else {
ZVAL_EMPTY_STRING(result);
}
return SUCCESS;
}
}
if (!can_ct_eval_func_call(name, num_args, args)) {
return FAILURE;
}
zend_execute_data *prev_execute_data = EG(current_execute_data);
zend_execute_data *execute_data, dummy_frame;
zend_op dummy_opline;
/* Add a dummy frame to get the correct strict_types behavior. */
memset(&dummy_frame, 0, sizeof(zend_execute_data));
memset(&dummy_opline, 0, sizeof(zend_op));
dummy_frame.func = (zend_function *) op_array;
dummy_frame.opline = &dummy_opline;
dummy_opline.opcode = ZEND_DO_FCALL;
execute_data = safe_emalloc(num_args, sizeof(zval), ZEND_CALL_FRAME_SLOT * sizeof(zval));
memset(execute_data, 0, sizeof(zend_execute_data));
execute_data->prev_execute_data = &dummy_frame;
EG(current_execute_data) = execute_data;
/* Enable suppression and counting of warnings. */
ZEND_ASSERT(EG(capture_warnings_during_sccp) == 0);
EG(capture_warnings_during_sccp) = 1;
EX(func) = func;
EX_NUM_ARGS() = num_args;
for (i = 0; i < num_args; i++) {
ZVAL_COPY(EX_VAR_NUM(i), args[i]);
}
ZVAL_NULL(result);
func->internal_function.handler(execute_data, result);
for (i = 0; i < num_args; i++) {
zval_ptr_dtor_nogc(EX_VAR_NUM(i));
}
zend_result retval = SUCCESS;
if (EG(exception)) {
zval_ptr_dtor(result);
zend_clear_exception();
retval = FAILURE;
}
if (EG(capture_warnings_during_sccp) > 1) {
zval_ptr_dtor(result);
retval = FAILURE;
}
EG(capture_warnings_during_sccp) = 0;
efree(execute_data);
EG(current_execute_data) = prev_execute_data;
return retval;
}
#define SET_RESULT(op, zv) do { \
if (ssa_op->op##_def >= 0) { \
set_value(scdf, ctx, ssa_op->op##_def, zv); \
} \
} while (0)
#define SET_RESULT_BOT(op) SET_RESULT(op, &ctx->bot)
#define SET_RESULT_TOP(op) SET_RESULT(op, &ctx->top)
#define SKIP_IF_TOP(op) if (IS_TOP(op)) return;
static void sccp_visit_instr(scdf_ctx *scdf, zend_op *opline, zend_ssa_op *ssa_op) {
sccp_ctx *ctx = (sccp_ctx *) scdf;
zval *op1, *op2, zv; /* zv is a temporary to hold result values */
op1 = get_op1_value(ctx, opline, ssa_op);
op2 = get_op2_value(ctx, opline, ssa_op);
switch (opline->opcode) {
case ZEND_ASSIGN:
/* The value of op1 is irrelevant here, because we are overwriting it
* -- unless it can be a reference, in which case we propagate a BOT.
* The result is also BOT in this case, because it might be a typed reference. */
if (IS_BOT(op1) && (ctx->scdf.ssa->var_info[ssa_op->op1_use].type & MAY_BE_REF)) {
SET_RESULT_BOT(op1);
SET_RESULT_BOT(result);
} else {
SET_RESULT(op1, op2);