/*
- * Project: libFIRM
- * File name: ir/opt/ldstopt.c
- * Purpose: optimization of function calls
- * Author:
- * Created:
- * CVS-ID: $Id$
- * Copyright: (c) 1998-2004 Universität Karlsruhe
- * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
+ * Copyright (C) 1995-2011 University of Karlsruhe. All right reserved.
+ *
+ * This file is part of libFirm.
+ *
+ * This file may be distributed and/or modified under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation and appearing in the file LICENSE.GPL included in the
+ * packaging of this file.
+ *
+ * Licensees holding valid libFirm Professional Edition licenses may use
+ * this file in accordance with the libFirm Commercial License.
+ * Agreement provided with the Software.
+ *
+ * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+ * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE.
*/
+
+/**
+ * @file
+ * @brief Optimization of function calls.
+ * @author Michael Beck
+ */
+#include "config.h"
+
+#include "opt_init.h"
+#include <stdbool.h>
+
#include "irnode_t.h"
#include "irgraph_t.h"
#include "irgmod.h"
#include "irgwalk.h"
-#include "irvrfy.h"
#include "dbginfo_t.h"
#include "irflag_t.h"
+#include "irloop_t.h"
#include "ircons.h"
-#include "eset.h"
-#include "funccall.h"
+#include "iredges_t.h"
+#include "irpass_t.h"
+#include "iroptimize.h"
+#include "analyze_irg_args.h"
#include "irhooks.h"
+#include "raw_bitset.h"
+#include "debug.h"
+
+DEBUG_ONLY(static firm_dbg_module_t *dbg;)
/**
- * The walker environment for rem_mem_from_real_fkt_calls
+ * The walker environment for updating function calls.
*/
-typedef struct _env_t {
- eset *pure_fkt; /**< set containing all real functions */
- int changed; /**< flag, is set if a graph was changed */
+typedef struct env_t {
+ ir_node *float_const_call_list; /**< The list of all floating const function calls that will be changed. */
+ ir_node *nonfloat_const_call_list; /**< The list of all non-floating const function calls that will be changed. */
+ ir_node *pure_call_list; /**< The list of all pure function calls that will be changed. */
+ ir_node *nothrow_call_list; /**< The list of all nothrow function calls that will be changed. */
+ ir_node *proj_list; /**< The list of all potential Proj nodes that must be fixed. */
} env_t;
+/** Ready IRG's are marked in the ready set. */
+static unsigned *ready_set;
+
+/** IRG's that are in progress are marked here. */
+static unsigned *busy_set;
+
+/**
+ * Walker: Collect all calls to const and pure functions
+ * to lists. Collect all Proj(Call) nodes into a Proj list.
+ */
+static void collect_const_and_pure_calls(ir_node *node, void *env)
+{
+ env_t *ctx = (env_t*)env;
+
+ if (is_Call(node)) {
+ ir_node *call = node;
+
+ /* set the link to NULL for all non-const/pure calls */
+ set_irn_link(call, NULL);
+ ir_node *ptr = get_Call_ptr(call);
+ if (!is_SymConst_addr_ent(ptr))
+ return;
+
+ ir_entity *ent = get_SymConst_entity(ptr);
+
+ unsigned prop = get_entity_additional_properties(ent);
+ if ((prop & (mtp_property_const|mtp_property_pure)) == 0)
+ return;
+
+ /* ok, if we get here we found a call to a const or a pure function */
+ if (prop & mtp_property_pure) {
+ set_irn_link(call, ctx->pure_call_list);
+ ctx->pure_call_list = call;
+ } else {
+ if (prop & mtp_property_has_loop) {
+ set_irn_link(call, ctx->nonfloat_const_call_list);
+ ctx->nonfloat_const_call_list = call;
+ } else {
+ set_irn_link(call, ctx->float_const_call_list);
+ ctx->float_const_call_list = call;
+ }
+ }
+ } else if (is_Proj(node)) {
+ /*
+ * Collect all memory and exception Proj's from
+ * calls.
+ */
+ ir_node *call = get_Proj_pred(node);
+ if (!is_Call(call))
+ return;
+
+ /* collect the Proj's in the Proj list */
+ switch (get_Proj_proj(node)) {
+ case pn_Call_M:
+ case pn_Call_X_except:
+ case pn_Call_X_regular:
+ set_irn_link(node, ctx->proj_list);
+ ctx->proj_list = node;
+ break;
+ default:
+ break;
+ }
+ }
+}
+
/**
- * remove memory from real function calls by rerouting
- * it's ProjM and connection the call with a NoMem node.
+ * Fix the list of collected Calls.
*
- * Note: By "real function" we understand a function that did neither
- * read nor write memory.
+ * @param irg the graph that contained calls to pure functions
+ * @param ctx context
*/
-static void rem_mem_from_real_fkt_calls(ir_node *node, void *env)
+static void fix_const_call_lists(ir_graph *irg, env_t *ctx)
{
- env_t *ctx = env;
- ir_node *call, *ptr, *mem;
- entity *ent;
+ bool exc_changed = false;
+
+ /* First step: fix all calls by removing their memory input and let
+ * them floating.
+ * The original memory input is preserved in their link fields. */
+ ir_node *next;
+ for (ir_node *call = ctx->float_const_call_list; call != NULL; call = next) {
+ next = (ir_node*)get_irn_link(call);
+ ir_node *mem = get_Call_mem(call);
+
+ set_irn_link(call, mem);
+ set_Call_mem(call, get_irg_no_mem(irg));
+
+ /*
+ * Unfortunately we cannot simply set the node to 'float'.
+ * There is a reason for that:
+ *
+ * - The call might be inside a loop/if that is NOT entered
+ * and calls a endless function. Setting the call to float
+ * would allow to move it out from the loop/if causing this
+ * function be called even if the loop/if is not entered ...
+ *
+ * This could be fixed using post-dominators for calls and Pin nodes
+ * but need some more analyzes to ensure that a call that potential
+ * never returns is not executed before some code that generates
+ * observable states...
+ */
+
+ /* finally, this call can float */
+ set_irn_pinned(call, op_pin_state_floats);
+ hook_func_call(irg, call);
+ }
- if (get_irn_op(node) != op_Proj || get_irn_mode(node) != mode_M)
- return;
+ /* Last step: fix all Proj's */
+ for (ir_node *proj = ctx->proj_list; proj != NULL; proj = next) {
+ next = (ir_node*)get_irn_link(proj);
+ ir_node *call = get_Proj_pred(proj);
+ ir_node *mem = (ir_node*)get_irn_link(call);
- /* look at Memory Proj's */
- call = get_Proj_pred(node);
- if (get_irn_op(call) != op_Call)
- return;
+ /* beware of calls in the pure call list */
+ if (!mem || is_Call(mem))
+ continue;
+ assert(get_irn_mode(mem) == mode_M);
- ptr = get_Call_ptr(call);
- if (get_irn_op(ptr) != op_SymConst || get_SymConst_kind(ptr) != symconst_addr_ent)
- return;
+ switch (get_Proj_proj(proj)) {
+ case pn_Call_M: {
+ /* in dead code there might be cycles where proj == mem */
+ if (proj != mem)
+ exchange(proj, mem);
+ break;
+ }
+ case pn_Call_X_except:
+ exc_changed = true;
+ exchange(proj, new_r_Bad(irg, mode_X));
+ break;
+ case pn_Call_X_regular: {
+ ir_node *block = get_nodes_block(call);
+ exc_changed = true;
+ exchange(proj, new_r_Jmp(block));
+ break;
+ }
+ default:
+ break;
+ }
+ }
- ent = get_SymConst_entity(ptr);
+ if (exc_changed) {
+ /* ... including exception edges */
+ clear_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE
+ | IR_GRAPH_PROPERTY_CONSISTENT_LOOPINFO);
+ }
+}
+
+/**
+ * Walker: Collect all calls to nothrow functions
+ * to lists. Collect all Proj(Call) nodes into a Proj list.
+ */
+static void collect_nothrow_calls(ir_node *node, void *env)
+{
+ env_t *ctx = (env_t*)env;
- if (! eset_contains(ctx->pure_fkt, ent))
- return;
+ if (is_Call(node)) {
+ ir_node *call = node;
- /* ok, if we get here we found a call to a pure function,
- * route the NoMem node to the call */
- mem = get_Call_mem(call);
+ /* set the link to NULL for all non-const/pure calls */
+ set_irn_link(call, NULL);
+ ir_node *ptr = get_Call_ptr(call);
+ if (!is_SymConst_addr_ent(ptr))
+ return;
- exchange(node, mem);
- set_Call_mem(call, new_r_NoMem(current_ir_graph));
+ ir_entity *ent = get_SymConst_entity(ptr);
- /* finally, this call can floats */
- set_irn_pinned(call, op_pin_state_floats);
+ unsigned prop = get_entity_additional_properties(ent);
+ if ((prop & mtp_property_nothrow) == 0)
+ return;
- hook_func_call(current_ir_graph, call);
+ /* ok, if we get here we found a call to a nothrow function */
+ set_irn_link(call, ctx->nothrow_call_list);
+ ctx->nothrow_call_list = call;
+ } else if (is_Proj(node)) {
+ /*
+ * Collect all memory and exception Proj's from
+ * calls.
+ */
+ ir_node *call = get_Proj_pred(node);
+ if (! is_Call(call))
+ return;
- ctx->changed = 1;
+ /* collect the Proj's in the Proj list */
+ switch (get_Proj_proj(node)) {
+ case pn_Call_M:
+ case pn_Call_X_except:
+ case pn_Call_X_regular:
+ set_irn_link(node, ctx->proj_list);
+ ctx->proj_list = node;
+ break;
+ default:
+ break;
+ }
+ }
}
-/*
- * optimize function calls by handling real functions
+/**
+ * Fix the list of collected nothrow Calls.
+ *
+ * @param irg the graph that contained calls to pure functions
+ * @param call_list the list of all call sites of const functions
+ * @param proj_list the list of all memory/exception Proj's of this call sites
*/
-void optimize_funccalls(void)
+static void fix_nothrow_call_list(ir_graph *irg, ir_node *call_list,
+ ir_node *proj_list)
{
- int i, n, j, k;
- int change;
- unsigned num_pure = 0;
- eset *pure_fkt = eset_create();
+ bool exc_changed = false;
- if (! get_opt_real_func_call())
- return;
+ /* First step: go through the list of calls and mark them. */
+ ir_node *next;
+ for (ir_node *call = call_list; call; call = next) {
+ next = (ir_node*)get_irn_link(call);
- /* first step: detect, which functions are pure, ie do NOT change any memory */
- for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
- ir_graph *irg = get_irp_irg(i);
- ir_node *end = get_irg_end(irg);
- ir_node *endbl = get_nodes_block(end);
+ /* current_ir_graph is in memory anyway, so it's a good marker */
+ set_irn_link(call, ¤t_ir_graph);
+ hook_func_call(irg, call);
+ }
- change = 0;
+ /* Second step: Remove all exception Proj's */
+ for (ir_node *proj = proj_list; proj; proj = next) {
+ next = (ir_node*)get_irn_link(proj);
+ ir_node *call = get_Proj_pred(proj);
- /* visit every Return */
- for (j = 0, k = get_Block_n_cfgpreds(endbl); j < k; ++j) {
- ir_node *ret = get_Block_cfgpred(endbl, j);
- ir_node *mem;
+ /* handle only marked calls */
+ if (get_irn_link(call) != ¤t_ir_graph)
+ continue;
- /* Bad nodes usually do NOT produce anything, so it's ok */
- if (is_Bad(ret))
- continue;
+ /* kill any exception flow */
+ switch (get_Proj_proj(proj)) {
+ case pn_Call_X_except:
+ exc_changed = true;
+ exchange(proj, new_r_Bad(irg, mode_X));
+ break;
+ case pn_Call_X_regular: {
+ ir_node *block = get_nodes_block(call);
+ exc_changed = true;
+ exchange(proj, new_r_Jmp(block));
+ break;
+ }
+ default:
+ break;
+ }
+ }
- mem = get_Return_mem(ret);
+ /* changes were done ... */
+ if (exc_changed) {
+ /* ... including exception edges */
+ clear_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE
+ | IR_GRAPH_PROPERTY_CONSISTENT_LOOPINFO);
+ }
+}
- /* Bad nodes usually do NOT produce anything, so it's ok */
- if (is_Bad(mem))
- continue;
+/* marking */
+#define SET_IRG_READY(irg) rbitset_set(ready_set, get_irg_idx(irg))
+#define IS_IRG_READY(irg) rbitset_is_set(ready_set, get_irg_idx(irg))
+#define SET_IRG_BUSY(irg) rbitset_set(busy_set, get_irg_idx(irg))
+#define CLEAR_IRG_BUSY(irg) rbitset_clear(busy_set, get_irg_idx(irg))
+#define IS_IRG_BUSY(irg) rbitset_is_set(busy_set, get_irg_idx(irg))
- change = mem != get_irg_initial_mem(irg);
- if (change)
- break;
- }
+/* forward */
+static mtp_additional_properties check_const_or_pure_function(ir_graph *irg, bool top);
- if (! change) {
- /* check, if a keep-alive exists */
- for (j = 0, k = get_End_n_keepalives(end); j < k; ++j) {
- ir_node *mem = get_End_keepalive(end, j);
+/**
+ * Calculate the bigger property of two. Handle the temporary flag right.
+ */
+static mtp_additional_properties max_property(mtp_additional_properties a,
+ mtp_additional_properties b)
+{
+ mtp_additional_properties t = (a | b) & mtp_temporary;
+ a &= ~mtp_temporary;
+ b &= ~mtp_temporary;
- if (mode_M != get_irn_mode(mem))
- continue;
+ if (a == mtp_no_property || b == mtp_no_property)
+ return mtp_no_property;
+ mtp_additional_properties r = a > b ? a : b;
+ return r | t;
+}
- change = mem != get_irg_initial_mem(irg);
- if (change)
- break;
- }
- }
+/**
+ * Follow the memory chain starting at node and determine
+ * the mtp_property.
+ *
+ * @return mtp_property_const if only calls of const functions are detected
+ * mtp_property_pure if only Loads and const/pure calls detected
+ * mtp_no_property else
+ */
+static mtp_additional_properties follow_mem_(ir_node *node)
+{
+ mtp_additional_properties mode = mtp_property_const;
+
+ for (;;) {
+ if (mode == mtp_no_property)
+ return mtp_no_property;
+
+ if (irn_visited_else_mark(node))
+ return mode;
+
+ switch (get_irn_opcode(node)) {
+ case iro_Proj:
+ node = get_Proj_pred(node);
+ break;
- if (! change) {
- eset_insert(pure_fkt, get_irg_entity(irg));
- ++num_pure;
- }
- }
+ case iro_NoMem:
+ /* finish here */
+ return mode;
- if (num_pure > 0) {
- env_t ctx;
+ case iro_Phi:
+ case iro_Sync:
+ /* do a dfs search */
+ for (int i = get_irn_arity(node) - 1; i >= 0; --i) {
+ mtp_additional_properties m = follow_mem_(get_irn_n(node, i));
+ mode = max_property(mode, m);
+ if (mode == mtp_no_property)
+ return mtp_no_property;
+ }
+ return mode;
- ctx.pure_fkt = pure_fkt;
+ case iro_Load:
+ /* Beware volatile Loads are NOT allowed in pure functions. */
+ if (get_Load_volatility(node) == volatility_is_volatile)
+ return mtp_no_property;
+ mode = max_property(mode, mtp_property_pure);
+ node = get_Load_mem(node);
+ break;
+
+ case iro_Call: {
+ /* A call is only tolerable if its either constant or pure. */
+ ir_node *ptr = get_Call_ptr(node);
+ if (!is_SymConst_addr_ent(ptr))
+ return mtp_no_property;
+
+ ir_entity *ent = get_SymConst_entity(ptr);
+ ir_graph *irg = get_entity_irg(ent);
+
+ mtp_additional_properties m;
+ if (irg == NULL) {
+ m = get_entity_additional_properties(ent) & (mtp_property_const|mtp_property_pure);
+ mode = max_property(mode, m);
+ } else {
+ /* we have a graph, analyze it. */
+ m = check_const_or_pure_function(irg, false);
+ mode = max_property(mode, m);
+ }
+ node = get_Call_mem(node);
+ break;
+ }
+
+ default:
+ return mtp_no_property;
+ }
+ }
+}
- /* all calls of pure functions can be transformed into FuncCalls */
- for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
- ir_graph *irg = get_irp_irg(i);
+/**
+ * Follow the memory chain starting at node and determine
+ * the mtp_property.
+ *
+ * @return mtp_property_const if only calls of const functions are detected
+ * mtp_property_pure if only Loads and const/pure calls detected
+ * mtp_no_property else
+ */
+static mtp_additional_properties follow_mem(ir_node *node, mtp_additional_properties mode)
+{
+ mtp_additional_properties m = follow_mem_(node);
+ return max_property(mode, m);
+}
+
+/**
+ * Check if a graph represents a const or a pure function.
+ *
+ * @param irg the graph to check
+ * @param top if set, this is the top call
+ */
+static mtp_additional_properties check_const_or_pure_function(ir_graph *irg, bool top)
+{
+ ir_entity *entity = get_irg_entity(irg);
+ ir_type *type = get_entity_type(entity);
+ size_t n_params = get_method_n_params(type);
+ mtp_additional_properties may_be_const = mtp_property_const;
+ mtp_additional_properties prop = get_entity_additional_properties(entity);
- ctx.changed = 0;
- irg_walk_graph(irg, NULL, rem_mem_from_real_fkt_calls, &ctx);
+ /* libfirm handles aggregate parameters by passing around pointers to
+ * stuff in memory, so if we have compound parameters we are never const */
+ for (size_t i = 0; i < n_params; ++i) {
+ ir_type *param = get_method_param_type(type, i);
+ if (is_compound_type(param)) {
+ prop &= ~mtp_property_const;
+ may_be_const = mtp_no_property;
+ }
+ }
+
+ if (prop & mtp_property_const) {
+ /* already marked as a const function */
+ return mtp_property_const;
+ }
+ if (prop & mtp_property_pure) {
+ /* already marked as a pure function */
+ return mtp_property_pure;
+ }
+
+ if (IS_IRG_READY(irg)) {
+ /* already checked */
+ return mtp_no_property;
+ }
+ if (IS_IRG_BUSY(irg)) {
+ /* We are still evaluate this method.
+ * The function (indirectly) calls itself and thus may not terminate. */
+ return mtp_no_property;
+ }
+ SET_IRG_BUSY(irg);
+
+ ir_node *end = get_irg_end(irg);
+ ir_node *endbl = get_nodes_block(end);
+ prop = may_be_const;
+
+ ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
+ inc_irg_visited(irg);
+ /* mark the initial mem: recursion of follow_mem() stops here */
+ mark_irn_visited(get_irg_initial_mem(irg));
+
+ /* visit every Return */
+ for (int j = get_Block_n_cfgpreds(endbl) - 1; j >= 0; --j) {
+ ir_node *node = get_Block_cfgpred(endbl, j);
+ unsigned code = get_irn_opcode(node);
+
+ /* Bad nodes usually do NOT produce anything, so it's ok */
+ if (code == iro_Bad)
+ continue;
+
+ if (code == iro_Return) {
+ ir_node *mem = get_Return_mem(node);
+
+ /* Bad nodes usually do NOT produce anything, so it's ok */
+ if (is_Bad(mem))
+ continue;
+
+ if (mem != get_irg_initial_mem(irg))
+ prop = max_property(prop, follow_mem(mem, prop));
+ } else {
+ /* Exception found. Cannot be const or pure. */
+ prop = mtp_no_property;
+ break;
+ }
+ if (prop == mtp_no_property)
+ break;
+ }
+
+ if (prop != mtp_no_property) {
+ /* check, if a keep-alive exists */
+ for (int j = get_End_n_keepalives(end) - 1; j >= 0; --j) {
+ ir_node *kept = get_End_keepalive(end, j);
+
+ if (is_Block(kept)) {
+ prop = mtp_no_property;
+ break;
+ }
+
+ if (mode_M != get_irn_mode(kept))
+ continue;
+
+ prop = max_property(prop, follow_mem(kept, prop));
+ if (prop == mtp_no_property)
+ break;
+ }
+ }
+
+ if (top) {
+ /* Set the property only if we are at top-level. */
+ if (prop != mtp_no_property) {
+ add_entity_additional_properties(entity, prop);
+ }
+ SET_IRG_READY(irg);
+ }
+ CLEAR_IRG_BUSY(irg);
+ ir_free_resources(irg, IR_RESOURCE_IRN_VISITED);
+ return prop;
+}
+
+/**
+ * Handle calls to const functions.
+ *
+ * @param ctx context
+ */
+static void handle_const_Calls(env_t *ctx)
+{
+ /* all calls of const functions can be transformed */
+ size_t n = get_irp_n_irgs();
+ for (size_t i = 0; i < n; ++i) {
+ ir_graph *irg = get_irp_irg(i);
- if (ctx.changed) {
- /* changes were done */
- set_irg_outs_inconsistent(irg);
- set_irg_loopinfo_state(current_ir_graph, loopinfo_cf_inconsistent);
- }
- }
- }
+ ctx->float_const_call_list = NULL;
+ ctx->nonfloat_const_call_list = NULL;
+ ctx->pure_call_list = NULL;
+ ctx->proj_list = NULL;
- eset_destroy(pure_fkt);
+ ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
+ irg_walk_graph(irg, NULL, collect_const_and_pure_calls, ctx);
+ fix_const_call_lists(irg, ctx);
+ ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
+
+ confirm_irg_properties(irg,
+ IR_GRAPH_PROPERTIES_CONTROL_FLOW
+ | IR_GRAPH_PROPERTY_ONE_RETURN
+ | IR_GRAPH_PROPERTY_MANY_RETURNS);
+ }
+}
+
+/**
+ * Handle calls to nothrow functions.
+ *
+ * @param ctx context
+ */
+static void handle_nothrow_Calls(env_t *ctx)
+{
+ /* all calls of const functions can be transformed */
+ size_t n = get_irp_n_irgs();
+ for (size_t i = 0; i < n; ++i) {
+ ir_graph *irg = get_irp_irg(i);
+
+ ctx->nothrow_call_list = NULL;
+ ctx->proj_list = NULL;
+
+ ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
+ irg_walk_graph(irg, NULL, collect_nothrow_calls, ctx);
+
+ if (ctx->nothrow_call_list)
+ fix_nothrow_call_list(irg, ctx->nothrow_call_list, ctx->proj_list);
+ ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
+ }
+}
+
+/**
+ * Check, whether a given node represents a return value of
+ * a malloc like function (ie, new heap allocated memory).
+ *
+ * @param node the node to check
+ */
+static bool is_malloc_call_result(const ir_node *node)
+{
+ if (is_Alloc(node) && get_Alloc_where(node) == heap_alloc) {
+ /* Firm style high-level allocation */
+ return true;
+ }
+ /* TODO: check mtp_malloc */
+ return false;
+}
+
+/**
+ * Update a property depending on a call property.
+ */
+static mtp_additional_properties update_property(mtp_additional_properties orig_prop, mtp_additional_properties call_prop)
+{
+ mtp_additional_properties t = (orig_prop | call_prop) & mtp_temporary;
+ mtp_additional_properties r = orig_prop & call_prop;
+ return r | t;
+}
+
+/**
+ * Check if a node is stored.
+ */
+static bool is_stored(const ir_node *n)
+{
+ const ir_node *ptr;
+
+ foreach_out_edge(n, edge) {
+ const ir_node *succ = get_edge_src_irn(edge);
+
+ switch (get_irn_opcode(succ)) {
+ case iro_Return:
+ case iro_Load:
+ case iro_Cmp:
+ /* ok */
+ break;
+ case iro_Store:
+ if (get_Store_value(succ) == n)
+ return true;
+ /* ok if its only the address input */
+ break;
+ case iro_Sel:
+ case iro_Cast:
+ case iro_Confirm:
+ if (is_stored(succ))
+ return true;
+ break;
+ case iro_Call:
+ ptr = get_Call_ptr(succ);
+ if (is_SymConst_addr_ent(ptr)) {
+ ir_entity *ent = get_SymConst_entity(ptr);
+ size_t i;
+
+ /* we know the called entity */
+ for (i = get_Call_n_params(succ); i > 0;) {
+ if (get_Call_param(succ, --i) == n) {
+ /* n is the i'th param of the call */
+ if (get_method_param_access(ent, i) & ptr_access_store) {
+ /* n is store in ent */
+ return true;
+ }
+ }
+ }
+ } else {
+ /* unknown call address */
+ return true;
+ }
+ break;
+ default:
+ /* bad, potential alias */
+ return true;
+ }
+ }
+ return false;
+}
+
+/**
+ * Check that the return value of an irg is not stored anywhere.
+ *
+ * return ~mtp_property_malloc if return values are stored, ~0 else
+ */
+static mtp_additional_properties check_stored_result(ir_graph *irg)
+{
+ ir_node *end_blk = get_irg_end_block(irg);
+ mtp_additional_properties res = ~mtp_no_property;
+
+ assure_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_OUT_EDGES);
+
+ for (int i = get_Block_n_cfgpreds(end_blk) - 1; i >= 0; --i) {
+ ir_node *pred = get_Block_cfgpred(end_blk, i);
+
+ if (! is_Return(pred))
+ continue;
+ for (size_t j = get_Return_n_ress(pred); j > 0;) {
+ const ir_node *irn = get_Return_res(pred, --j);
+
+ if (is_stored(irn)) {
+ /* bad, might create an alias */
+ res = ~mtp_property_malloc;
+ goto finish;
+ }
+ }
+ }
+finish:
+ confirm_irg_properties(irg, IR_GRAPH_PROPERTIES_ALL);
+ return res;
+}
+
+/**
+ * Check if a graph represents a nothrow or a malloc function.
+ *
+ * @param irg the graph to check
+ * @param top if set, this is the top call
+ */
+static mtp_additional_properties check_nothrow_or_malloc(ir_graph *irg, bool top)
+{
+ mtp_additional_properties curr_prop
+ = mtp_property_malloc | mtp_property_nothrow;
+
+ ir_entity *ent = get_irg_entity(irg);
+ if (IS_IRG_READY(irg)) {
+ /* already checked */
+ return get_entity_additional_properties(ent);
+ }
+ if (IS_IRG_BUSY(irg)) {
+ /* we are still evaluate this method. Be optimistic,
+ return the best possible so far but mark the result as temporary. */
+ return mtp_temporary | mtp_property_malloc | mtp_property_nothrow;
+ }
+ SET_IRG_BUSY(irg);
+
+ ir_type *mtp = get_entity_type(ent);
+ if (get_method_n_ress(mtp) <= 0)
+ curr_prop &= ~mtp_property_malloc;
+
+ ir_node *end_blk = get_irg_end_block(irg);
+ for (int i = get_Block_n_cfgpreds(end_blk) - 1; i >= 0; --i) {
+ ir_node *pred = get_Block_cfgpred(end_blk, i);
+
+ if (is_Return(pred)) {
+ if (curr_prop & mtp_property_malloc) {
+ /* check, if malloc is called here */
+ for (size_t j = get_Return_n_ress(pred); j > 0;) {
+ ir_node *res = get_Return_res(pred, --j);
+
+ /* skip Confirms and Casts */
+ res = skip_HighLevel_ops(res);
+ /* skip Proj's */
+ while (is_Proj(res))
+ res = get_Proj_pred(res);
+ if (is_malloc_call_result(res)) {
+ /* ok, this is a malloc */
+ } else if (is_Call(res)) {
+ ir_node *ptr = get_Call_ptr(res);
+
+ if (is_SymConst_addr_ent(ptr)) {
+ /* a direct call */
+ ir_entity *ent = get_SymConst_entity(ptr);
+ ir_graph *callee = get_entity_irg(ent);
+
+ if (callee == irg) {
+ /* A self-recursive call. The property did not depend on this call. */
+ } else if (callee != NULL) {
+ mtp_additional_properties prop = check_nothrow_or_malloc(callee, false);
+ curr_prop = update_property(curr_prop, prop);
+ } else {
+ curr_prop = update_property(curr_prop, get_entity_additional_properties(ent));
+ }
+ } else {
+ /* unknown call */
+ curr_prop &= ~mtp_property_malloc;
+ }
+ } else {
+ /* unknown return value */
+ curr_prop &= ~mtp_property_malloc;
+ }
+ }
+ }
+ } else if (curr_prop & mtp_property_nothrow) {
+ /* exception flow detected */
+ pred = skip_Proj(pred);
+
+ if (is_Call(pred)) {
+ ir_node *ptr = get_Call_ptr(pred);
+
+ if (is_SymConst_addr_ent(ptr)) {
+ /* a direct call */
+ ir_entity *ent = get_SymConst_entity(ptr);
+ ir_graph *callee = get_entity_irg(ent);
+
+ if (callee == irg) {
+ /* A self-recursive call. The property did not depend on this call. */
+ } else if (callee != NULL) {
+ /* Note: we check here for nothrow only, so do NOT reset the malloc property */
+ mtp_additional_properties prop = check_nothrow_or_malloc(callee, false) | mtp_property_malloc;
+ curr_prop = update_property(curr_prop, prop);
+ } else {
+ if ((get_entity_additional_properties(ent) & mtp_property_nothrow) == 0)
+ curr_prop &= ~mtp_property_nothrow;
+ }
+ } else {
+ /* unknown call */
+ curr_prop &= ~mtp_property_nothrow;
+ }
+ } else {
+ /* real exception flow possible. */
+ curr_prop &= ~mtp_property_nothrow;
+ }
+ }
+ if ((curr_prop & ~mtp_temporary) == mtp_no_property) {
+ /* no need to search further */
+ break;
+ }
+ }
+
+ if (curr_prop & mtp_property_malloc) {
+ /* Note that the malloc property means not only return newly allocated
+ * memory, but also that this memory is ALIAS FREE.
+ * To ensure that, we do NOT allow that the returned memory is somewhere
+ * stored. */
+ curr_prop &= check_stored_result(irg);
+ }
+
+ if (curr_prop != mtp_no_property
+ && (top || (curr_prop & mtp_temporary) == 0)) {
+ /* We use the temporary flag here to mark an optimistic result.
+ * Set the property only if we are sure that it does NOT base on
+ * temporary results OR if we are at top-level. */
+ add_entity_additional_properties(ent, curr_prop & ~mtp_temporary);
+ SET_IRG_READY(irg);
+ }
+ if (top)
+ SET_IRG_READY(irg);
+ CLEAR_IRG_BUSY(irg);
+ return curr_prop;
+}
+
+/**
+ * When a function was detected as "const", it might be moved out of loops.
+ * This might be dangerous if the graph can contain endless loops.
+ */
+static void check_for_possible_endless_loops(ir_graph *irg)
+{
+ assure_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_LOOPINFO);
+
+ ir_loop *root_loop = get_irg_loop(irg);
+ if (root_loop->flags & loop_outer_loop) {
+ ir_entity *ent = get_irg_entity(irg);
+ add_entity_additional_properties(ent, mtp_property_has_loop);
+ }
+
+ confirm_irg_properties(irg, IR_GRAPH_PROPERTIES_ALL);
+}
+
+void optimize_funccalls(void)
+{
+ /* prepare: mark all graphs as not analyzed */
+ size_t last_idx = get_irp_last_idx();
+ ready_set = rbitset_malloc(last_idx);
+ busy_set = rbitset_malloc(last_idx);
+
+ /* first step: detect, which functions are nothrow or malloc */
+ DB((dbg, LEVEL_2, "Detecting nothrow and malloc properties ...\n"));
+ for (size_t i = 0, n = get_irp_n_irgs(); i < n; ++i) {
+ ir_graph *irg = get_irp_irg(i);
+ unsigned prop = check_nothrow_or_malloc(irg, true);
+
+ if (prop & mtp_property_nothrow) {
+ DB((dbg, LEVEL_2, "%+F has the nothrow property\n", irg));
+ } else if (prop & mtp_property_malloc) {
+ DB((dbg, LEVEL_2, "%+F has the malloc property\n", irg));
+ }
+ }
+
+ /* second step: remove exception edges: this must be done before the
+ detection of const and pure functions take place. */
+ env_t ctx;
+ handle_nothrow_Calls(&ctx);
+
+ rbitset_clear_all(ready_set, last_idx);
+ rbitset_clear_all(busy_set, last_idx);
+
+ /* third step: detect, which functions are const or pure */
+ DB((dbg, LEVEL_2, "Detecting const and pure properties ...\n"));
+ for (size_t i = 0, n = get_irp_n_irgs(); i < n; ++i) {
+ ir_graph *irg = get_irp_irg(i);
+ unsigned prop = check_const_or_pure_function(irg, true);
+
+ if (prop & mtp_property_const) {
+ DB((dbg, LEVEL_2, "%+F has the const property\n", irg));
+ check_for_possible_endless_loops(irg);
+ } else if (prop & mtp_property_pure) {
+ DB((dbg, LEVEL_2, "%+F has the pure property\n", irg));
+ }
+ }
+
+ handle_const_Calls(&ctx);
+
+ xfree(busy_set);
+ xfree(ready_set);
+}
+
+void firm_init_funccalls(void)
+{
+ FIRM_DBG_REGISTER(dbg, "firm.opt.funccalls");
+}
+
+ir_prog_pass_t *optimize_funccalls_pass(const char *name)
+{
+ return def_prog_pass(name ? name : "funccall", optimize_funccalls);
}
projects / libfirm / blobdiff