Zend/Optimizer/scdf: add const qualifiers

Author: Girgias

Zend/Optimizer/scdf.c

@@ -70,7 +70,7 @@ void scdf_mark_edge_feasible(scdf_ctx *scdf, int from, int to) {
 	} else {
 		/* Block is already executable, only a new edge became feasible.
 		 * Reevaluate phi nodes to account for changed source operands. */
-		zend_ssa_block *ssa_block = &scdf->ssa->blocks[to];
+		const zend_ssa_block *ssa_block = &scdf->ssa->blocks[to];
 		zend_ssa_phi *phi;
 		for (phi = ssa_block->phis; phi; phi = phi->next) {
 			zend_bitset_excl(scdf->phi_var_worklist, phi->ssa_var);
@@ -101,7 +101,7 @@ void scdf_init(zend_optimizer_ctx *ctx, scdf_ctx *scdf, zend_op_array *op_array,
 }
 
 void scdf_solve(scdf_ctx *scdf, const char *name) {
-	zend_ssa *ssa = scdf->ssa;
+	const zend_ssa *ssa = scdf->ssa;
 	DEBUG_PRINT("Start SCDF solve (%s)\n", name);
 	while (!zend_bitset_empty(scdf->instr_worklist, scdf->instr_worklist_len)
 		|| !zend_bitset_empty(scdf->phi_var_worklist, scdf->phi_var_worklist_len)
@@ -140,7 +140,7 @@ void scdf_solve(scdf_ctx *scdf, const char *name) {
 		while ((i = zend_bitset_pop_first(scdf->block_worklist, scdf->block_worklist_len)) >= 0) {
 			/* This block is now live. Interpret phis and instructions in it. */
 			zend_basic_block *block = &ssa->cfg.blocks[i];
-			zend_ssa_block *ssa_block = &ssa->blocks[i];
+			const zend_ssa_block *ssa_block = &ssa->blocks[i];
 
 			DEBUG_PRINT("Pop block %d from worklist\n", i);
 			zend_bitset_incl(scdf->executable_blocks, i);
@@ -185,7 +185,7 @@ void scdf_solve(scdf_ctx *scdf, const char *name) {
  * not eliminate the latter. While it cannot be reached, the FREE opcode of the loop var
  * is necessary for the correctness of temporary compaction. */
 static bool is_live_loop_var_free(
-		scdf_ctx *scdf, const zend_op *opline, const zend_ssa_op *ssa_op) {
+		const scdf_ctx *scdf, const zend_op *opline, const zend_ssa_op *ssa_op) {
 	if (!zend_optimizer_is_loop_var_free(opline)) {
 		return false;
 	}
@@ -195,7 +195,7 @@ static bool is_live_loop_var_free(
 		return false;
 	}
 
-	zend_ssa_var *ssa_var = &scdf->ssa->vars[var];
+	const zend_ssa_var *ssa_var = &scdf->ssa->vars[var];
 	uint32_t def_block;
 	if (ssa_var->definition >= 0) {
 		def_block = scdf->ssa->cfg.map[ssa_var->definition];
@@ -205,7 +205,7 @@ static bool is_live_loop_var_free(
 	return zend_bitset_in(scdf->executable_blocks, def_block);
 }
 
-static bool kept_alive_by_loop_var_free(scdf_ctx *scdf, const zend_basic_block *block) {
+static bool kept_alive_by_loop_var_free(const scdf_ctx *scdf, const zend_basic_block *block) {
 	const zend_op_array *op_array = scdf->op_array;
 	const zend_cfg *cfg = &scdf->ssa->cfg;
 	if (!(cfg->flags & ZEND_FUNC_FREE_LOOP_VAR)) {
@@ -220,7 +220,7 @@ static bool kept_alive_by_loop_var_free(scdf_ctx *scdf, const zend_basic_block *
 	return false;
 }
 
-static uint32_t cleanup_loop_var_free_block(scdf_ctx *scdf, zend_basic_block *block) {
+static uint32_t cleanup_loop_var_free_block(const scdf_ctx *scdf, const zend_basic_block *block) {
 	zend_ssa *ssa = scdf->ssa;
 	const zend_op_array *op_array = scdf->op_array;
 	const zend_cfg *cfg = &ssa->cfg;
@@ -256,12 +256,12 @@ static uint32_t cleanup_loop_var_free_block(scdf_ctx *scdf, zend_basic_block *bl
 /* Removes unreachable blocks. This will remove both the instructions (and phis) in the
  * blocks, as well as remove them from the successor / predecessor lists and mark them
  * unreachable. Blocks already marked unreachable are not removed. */
-uint32_t scdf_remove_unreachable_blocks(scdf_ctx *scdf) {
+uint32_t scdf_remove_unreachable_blocks(const scdf_ctx *scdf) {
 	zend_ssa *ssa = scdf->ssa;
 	int i;
 	uint32_t removed_ops = 0;
 	for (i = 0; i < ssa->cfg.blocks_count; i++) {
-		zend_basic_block *block = &ssa->cfg.blocks[i];
+		const zend_basic_block *block = &ssa->cfg.blocks[i];
 		if (!zend_bitset_in(scdf->executable_blocks, i) && (block->flags & ZEND_BB_REACHABLE)) {
 			if (!kept_alive_by_loop_var_free(scdf, block)) {
 				removed_ops += block->len;

Zend/Optimizer/scdf.h

@@ -49,10 +49,10 @@ typedef struct _scdf_ctx {
 void scdf_init(zend_optimizer_ctx *ctx, scdf_ctx *scdf, zend_op_array *op_array, zend_ssa *ssa);
 void scdf_solve(scdf_ctx *scdf, const char *name);
 
-uint32_t scdf_remove_unreachable_blocks(scdf_ctx *scdf);
+uint32_t scdf_remove_unreachable_blocks(const scdf_ctx *scdf);
 
 /* Add uses to worklist */
-static inline void scdf_add_to_worklist(scdf_ctx *scdf, int var_num) {
+static inline void scdf_add_to_worklist(const scdf_ctx *scdf, int var_num) {
 	const zend_ssa *ssa = scdf->ssa;
 	const zend_ssa_var *var = &ssa->vars[var_num];
 	int use;
@@ -66,7 +66,7 @@ static inline void scdf_add_to_worklist(scdf_ctx *scdf, int var_num) {
 }
 
 /* This should usually not be necessary, however it's used for type narrowing. */
-static inline void scdf_add_def_to_worklist(scdf_ctx *scdf, int var_num) {
+static inline void scdf_add_def_to_worklist(const scdf_ctx *scdf, int var_num) {
 	const zend_ssa_var *var = &scdf->ssa->vars[var_num];
 	if (var->definition >= 0) {
 		zend_bitset_incl(scdf->instr_worklist, var->definition);