X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Ffunccall.c;h=b084fea834128fd44bd53cf841f62b9cbad144c2;hb=5f4790a24705590534c5c7a96d4ce38fe9234540;hp=51c5c6efd1068a4d9ed5ee2433202a40c1f5ca2c;hpb=b55caf0fb4aad37ee84e7b5f99abe58b88a6f1d3;p=libfirm

diff --git a/ir/opt/funccall.c b/ir/opt/funccall.c
index 51c5c6efd..b084fea83 100644
--- a/ir/opt/funccall.c
+++ b/ir/opt/funccall.c
@@ -1,11 +1,11 @@
 /*
  * Project:     libFIRM
- * File name:   ir/opt/ldstopt.c
+ * File name:   ir/opt/funccall.c
  * Purpose:     optimization of function calls
- * Author:
+ * Author:      Michael Beck
  * Created:
  * CVS-ID:      $Id$
- * Copyright:   (c) 1998-2004 Universität Karlsruhe
+ * Copyright:   (c) 1998-2006 Universität Karlsruhe
  * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
  */
 #include "irnode_t.h"
@@ -16,151 +16,511 @@
 #include "dbginfo_t.h"
 #include "irflag_t.h"
 #include "ircons.h"
-#include "eset.h"
 #include "funccall.h"
 #include "irhooks.h"
 
 /**
- * The walker environment for rem_mem_from_real_fkt_calls
+ * The walker environment for rem_mem_from_const_fkt_calls
  */
 typedef struct _env_t {
-  eset *pure_fkt;   /**< set containing all real functions */
-  int  changed;     /**< flag, is set if a graph was changed */
+  int  n_calls_removed_SymConst;
+  int  n_calls_removed_Sel;
+  ir_node *const_call_list;       /**< The list of all 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 *proj_list;             /**< The list of all potential Proj nodes that must be fixed. */
 } env_t;
 
 /**
- * remove memory from real function calls by rerouting
- * it's ProjM and connection the call with a NoMem node.
- *
- * Note: By "real function" we understand a function that did neither
- * read nor write memory.
+ * Collect all calls to const and pure functions
+ * to lists. Collect all Proj(Call) nodes into a Proj list.
  */
-static void rem_mem_from_real_fkt_calls(ir_node *node, void *env)
+static void collect_calls(ir_node *node, void *env)
 {
   env_t *ctx = env;
-  ir_node *call, *ptr, *mem;
+  ir_node *call, *ptr;
   entity *ent;
+  unsigned mode;
 
-  if (get_irn_op(node) != op_Proj || get_irn_mode(node) != mode_M)
-    return;
+  if (is_Call(node)) {
+    call = node;
 
-  /* look at Memory Proj's */
-  call = get_Proj_pred(node);
-  if (get_irn_op(call) != op_Call)
-    return;
+    /* set the link to NULL for all non-const/pure calls */
+    set_irn_link(call, NULL);
+    ptr = get_Call_ptr(call);
+    if (get_irn_op(ptr) == op_SymConst && get_SymConst_kind(ptr) == symconst_addr_ent) {
+      ent = get_SymConst_entity(ptr);
 
-  ptr = get_Call_ptr(call);
-  if (get_irn_op(ptr) != op_SymConst || get_SymConst_kind(ptr) != symconst_addr_ent)
-    return;
+      mode = get_entity_additional_properties(ent);
+      if ((mode & (mtp_property_const|mtp_property_pure)) == 0)
+        return;
+      ++ctx->n_calls_removed_SymConst;
+    } else if (get_opt_closed_world() &&
+             is_Sel(ptr) &&
+	         get_irg_callee_info_state(current_ir_graph) == irg_callee_info_consistent) {
+      /* If all possible callees are const functions, we can remove the memory edge. */
+      int i, n_callees = get_Call_n_callees(call);
+      if (n_callees == 0)
+        /* This is kind of strange:  dying code or a Call that will raise an exception
+	       when executed as there is no implementation to call.  So better not
+	       optimize. */
+        return;
 
-  ent = get_SymConst_entity(ptr);
+      /* note that const function are a subset of pure ones */
+      mode = mtp_property_const | mtp_property_pure;
+      for (i = 0; i < n_callees; ++i) {
+        ent = get_Call_callee(call, i);
+        if (ent == unknown_entity) {
+          /* we don't know which entity is called here */
+          return;
+        }
+        mode &= get_entity_additional_properties(ent);
+        if (mode == 0)
+          return;
+      }
+      ++ctx->n_calls_removed_Sel;
+    } else
+      return;
 
-  if (! eset_contains(ctx->pure_fkt, ent))
-    return;
+    /* ok, if we get here we found a call to a const or a pure function */
+    if (mode & mtp_property_pure) {
+      set_irn_link(call, ctx->pure_call_list);
+      ctx->pure_call_list = call;
+    } else {
+      set_irn_link(call, ctx->const_call_list);
+      ctx->const_call_list = call;
+    }
+  } else if (is_Proj(node)) {
+    /*
+     * Collect all memory and exception Proj's from
+     * calls.
+     */
+    call = get_Proj_pred(node);
+    if (! is_Call(call))
+      return;
 
-  /* 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);
+    /* collect the Proj's in the Proj list */
+    switch (get_Proj_proj(node)) {
+    case pn_Call_M_regular:
+    case pn_Call_X_except:
+    case pn_Call_M_except:
+      set_irn_link(node, ctx->proj_list);
+      ctx->proj_list = node;
+      break;
+    default:
+      break;
+    }
+  }
+}  /* collect_calls */
 
-  exchange(node, mem);
-  set_Call_mem(call, new_r_NoMem(current_ir_graph));
+/**
+ * Fix the list of collected 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
+ */
+static void fix_const_call_list(ir_graph *irg, ir_node *call_list, ir_node *proj_list) {
+  ir_node *call, *next, *mem, *proj;
+  int exc_changed = 0;
 
-  /* finally, this call can floats */
-  set_irn_pinned(call, op_pin_state_floats);
+  /* First step: fix all calls by removing it's memory input.
+     It's original memory input is preserved in their link fields. */
+  for (call = call_list; call; call = next) {
+    next = get_irn_link(call);
+    mem  = get_Call_mem(call);
 
-  hook_func_call(current_ir_graph, call);
+    set_irn_link(call, mem);
+    set_Call_mem(call, get_irg_no_mem(irg));
 
-  ctx->changed = 1;
-}
+    /*
+     * Sorrily 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...
+     */
 
-/*
- * optimize function calls by handling real functions
+    /* finally, this call can float
+    set_irn_pinned(call, op_pin_state_floats); */
+    hook_func_call(irg, call);
+  }
+
+  /* Second step: fix all Proj's */
+  for (proj = proj_list; proj; proj = next) {
+    next = get_irn_link(proj);
+    call = get_Proj_pred(proj);
+    mem  = get_irn_link(call);
+
+    /* beware of calls in the pure call list */
+    if (! mem || get_irn_op(mem) == op_Call)
+      continue;
+    assert(get_irn_mode(mem) == mode_M);
+
+    switch (get_Proj_proj(proj)) {
+    case pn_Call_M_regular: {
+      /* in dead code there might be cycles where proj == mem */
+      if (proj != mem)
+        exchange(proj, mem);
+    } break;
+    case pn_Call_X_except:
+    case pn_Call_M_except:
+      exc_changed = 1;
+      exchange(proj, get_irg_bad(irg));
+      break;
+    default:
+      ;
+    }
+  }
+
+  /* changes were done ... */
+  set_irg_outs_inconsistent(irg);
+  set_irg_loopinfo_state(current_ir_graph, loopinfo_cf_inconsistent);
+
+  if (exc_changed) {
+    /* ... including exception edges */
+    set_irg_doms_inconsistent(irg);
+  }
+}  /* fix_call_list */
+
+#if 0
+/**
+ * Check if a graph represents a const function.
+ *
+ * @param irg  the graph
  */
-void optimize_funccalls(void)
+static int is_const_function(ir_graph *irg)
 {
-  int i, n, j, k;
-  int change;
-  unsigned num_pure = 0;
-  eset *pure_fkt = eset_create();
+  ir_node *end, *endbl;
+  int j, change;
 
-  if (! get_opt_real_func_call())
-    return;
+  if (get_irg_additional_properties(irg) & mtp_property_const) {
+    /* already marked as a const function */
+    return 0;
+  }
 
-  /* 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);
+  end   = get_irg_end(irg);
+  endbl = get_nodes_block(end);
+  change = 0;
 
-    change = 0;
+  /* visit every Return */
+  for (j = get_Block_n_cfgpreds(endbl) - 1; j >= 0; --j) {
+    ir_node *node = get_Block_cfgpred(endbl, j);
+    ir_op   *op   = get_irn_op(node);
+    ir_node *mem;
 
-    /* visit every Return */
-    for (j = 0, k = get_Block_n_cfgpreds(endbl); j < k; ++j) {
-      ir_node *node = get_Block_cfgpred(endbl, j);
-      ir_op   *op   = get_irn_op(node);
-      ir_node *mem;
+    /* Bad nodes usually do NOT produce anything, so it's ok */
+    if (op == op_Bad)
+      continue;
+
+    if (op == op_Return) {
+      mem = get_Return_mem(node);
 
       /* Bad nodes usually do NOT produce anything, so it's ok */
-      if (op == op_Bad)
+      if (is_Bad(mem))
         continue;
 
-      if (op == op_Return) {
-        mem = get_Return_mem(node);
+      change = mem != get_irg_initial_mem(irg);
+      if (change)
+        break;
+    }
+    else {
+      /* exception found */
+      change = 1;
+      break;
+    }
+  }
 
-        /* Bad nodes usually do NOT produce anything, so it's ok */
-        if (is_Bad(mem))
-          continue;
+  if (! change) {
+    /* check, if a keep-alive exists */
+    for (j = get_End_n_keepalives(end) - 1; j >= 0; --j) {
+      ir_node *mem = get_End_keepalive(end, j);
 
-        change = mem != get_irg_initial_mem(irg);
-        if (change)
-          break;
-      }
-      else {
-        /* exception found */
-        change = 1;
+      if (mode_M != get_irn_mode(mem))
+        continue;
+
+      change = mem != get_irg_initial_mem(irg);
+      if (change)
         break;
-      }
     }
+  }
+
+  if (! change) {
+    /* no memory changes found, it's a const function */
+    set_irg_additional_property(irg, mtp_property_const);
+    return 1;
+  }
+  return 0;
+}  /* is_const_function */
+#endif
+
+/* a marker */
+static char _mark;
+#define MARK &_mark
+
+#define UNMARK_IRG(irg)     set_irg_link((irg), NULL)
+#define MARK_IRG(irg)       set_irg_link((irg), MARK)
+#define IS_IRG_MARKED(irg)  (get_irg_link(irg) == MARK)
 
-    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);
+/* forward */
+static int is_pure_function(ir_graph *irg);
 
-        if (mode_M != get_irn_mode(mem))
-          continue;
+#define UMAX(a,b) (a) > (b) ? (a) : (b)
 
-        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
+ *         bad_property else
+ */
+static unsigned _follow_mem(ir_node *node) {
+  unsigned m, mode = mtp_property_const;
+  ir_node  *ptr;
+  int i;
+
+  for (;;) {
+    if (irn_visited(node))
+      return mode;
+
+    mark_irn_visited(node);
+
+    switch (get_irn_opcode(node)) {
+    case iro_Proj:
+      node = get_Proj_pred(node);
+      break;
+
+    case iro_NoMem:
+      /* finish here */
+      return mode;
+
+    case iro_Phi:
+    case iro_Sync:
+      for (i = get_irn_arity(node) - 1; i >= 0; --i) {
+        mode &= _follow_mem(get_irn_n(node, i));
       }
-    }
+      break;
 
-    if (! change) {
-      eset_insert(pure_fkt, get_irg_entity(irg));
-      ++num_pure;
+    case iro_Load:
+      /* Beware volatile Loads are NOT allowed in pure functions */
+      if (get_Load_volatility(node) == volatility_is_volatile)
+        return 0;
+      mode = mtp_property_pure;
+      node = get_Load_mem(node);
+      break;
+
+    case iro_Call:
+      /* a call is only tolerable if its either constant or pure */
+      ptr = get_Call_ptr(node);
+      if (get_irn_op(ptr) == op_SymConst &&
+          get_SymConst_kind(ptr) == symconst_addr_ent) {
+        entity   *ent = get_SymConst_entity(ptr);
+        ir_graph *irg = get_entity_irg(ent);
+
+        if (irg == current_ir_graph) {
+          /* A recursive call. The did not mode depend on this call */
+        }
+        else if (irg == NULL) {
+          m = get_entity_additional_properties(ent) & (mtp_property_const|mtp_property_pure);
+          if (! m)
+            return 0;
+          mode = UMAX(mode, m);
+        }
+        else if (irg != NULL) {
+          /* we have a graph. Check if it is already analyzed */
+          if (IS_IRG_MARKED(irg))
+            (void)is_pure_function(irg);
+
+          m = get_irg_additional_properties(irg) & (mtp_property_const|mtp_property_pure);
+          if (! m)
+            return 0;
+          mode = UMAX(mode, m);
+        }
+      }
+      else
+        return 0;
+      node = get_Call_mem(node);
+      break;
+
+    default:
+      return 0;
     }
   }
+}  /* follow_mem */
 
-  if (num_pure > 0) {
-    env_t ctx;
+/**
+ * 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
+ *         0 else
+ */
+static unsigned follow_mem(ir_graph *irg, ir_node *node, unsigned mode) {
+  unsigned m;
+
+  inc_irg_visited(irg);
+  /* mark the initial mem: recursion stops here */
+  mark_irn_visited(get_irg_initial_mem(irg));
+  m = _follow_mem(node);
+  if (! m)
+    return 0;
+  return UMAX(mode, m);
+}  /* follow_mwm */
+
+/*
+ * Check if a graph represents a pure function.
+ *
+ * @param irg  the graph
+ */
+static int is_pure_function(ir_graph *irg) {
+  ir_node *end, *endbl;
+  int j;
+  unsigned mode = get_irg_additional_properties(irg);
+  ir_graph *rem = current_ir_graph;
 
-    ctx.pure_fkt = pure_fkt;
+  if (mode & mtp_property_const) {
+    /* already marked as a const function */
+    return mtp_property_const;
+  }
+  if (mode & mtp_property_pure) {
+    /* already marked as a pure function */
+    return mtp_property_const;
+  }
 
-    /* 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);
+  if (! IS_IRG_MARKED(irg))
+    return 0;
+  UNMARK_IRG(irg);
 
-      ctx.changed = 0;
-      irg_walk_graph(irg, NULL, rem_mem_from_real_fkt_calls, &ctx);
+  end   = get_irg_end(irg);
+  endbl = get_nodes_block(end);
+  mode  = mtp_property_const;
 
-      if (ctx.changed) {
-        /* changes were done */
-        set_irg_outs_inconsistent(irg);
-        set_irg_loopinfo_state(current_ir_graph, loopinfo_cf_inconsistent);
-      }
+  current_ir_graph = irg;
+
+  /* visit every Return */
+  for (j = get_Block_n_cfgpreds(endbl) - 1; j >= 0; --j) {
+    ir_node *node = get_Block_cfgpred(endbl, j);
+    ir_op   *op   = get_irn_op(node);
+    ir_node *mem;
+
+    /* Bad nodes usually do NOT produce anything, so it's ok */
+    if (op == op_Bad)
+      continue;
+
+    if (op == op_Return) {
+      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))
+        mode = follow_mem(irg, mem, mode);
+    }
+    else {
+      /* exception found. */
+      mode = follow_mem(irg, node, mode);
+      break;
+    }
+    if (mode == 0)
+      break;
+  }
+
+  if (mode != 0) {
+    /* check, if a keep-alive exists */
+    for (j = get_End_n_keepalives(end) - 1; j >= 0; --j) {
+      ir_node *mem = get_End_keepalive(end, j);
+
+      if (mode_M != get_irn_mode(mem))
+        continue;
+
+      mode = follow_mem(irg, mem, mode);
+      if (mode == 0)
+        break;
     }
   }
 
-  eset_destroy(pure_fkt);
-}
+  if (mode)
+    set_irg_additional_property(irg, mode);
+  current_ir_graph = rem;
+  return mode;
+}  /* is_pure_function */
+
+/**
+ * Handle calls to const functions.
+ */
+static void handle_const_Calls(env_t *ctx)
+{
+  int i;
+
+  ctx->n_calls_removed_SymConst = 0;
+  ctx->n_calls_removed_Sel      = 0;
+
+  /* all calls of const functions can be transformed */
+  for (i = get_irp_n_irgs() - 1; i >= 0; --i) {
+    ir_graph *irg  = get_irp_irg(i);
+
+    ctx->const_call_list = NULL;
+    ctx->pure_call_list  = NULL;
+    ctx->proj_list = NULL;
+    irg_walk_graph(irg, NULL, collect_calls, ctx);
+
+    if (ctx->const_call_list)
+      fix_const_call_list(irg, ctx->const_call_list, ctx->proj_list);
+  }
+}  /* handle_const_Calls */
+
+/*
+ * optimize function calls by handling const functions
+ */
+void optimize_funccalls(int force_run)
+{
+  int i, n;
+  unsigned num_const = 0;
+  unsigned num_pure  = 0;
+
+  if (! get_opt_function_call())
+    return;
+
+  /* prepare: mark all graphs as not analyzed */
+  n = get_irp_n_irgs();
+  for (i = n - 1; i >= 0; --i)
+    MARK_IRG(get_irp_irg(i));
+
+  /* first step: detect, which functions are const, i.e. do NOT touch any memory */
+  for (i = n - 1; i >= 0; --i) {
+    ir_graph *irg = get_irp_irg(i);
+    unsigned mode = is_pure_function(irg);
+
+    if (mode & mtp_property_const)
+      ++num_const;
+    else if (mode & mtp_property_pure)
+      ++num_pure;
+  }
+
+  if (force_run || num_const > 0) {
+    env_t ctx;
+
+    handle_const_Calls(&ctx);
+    if (get_firm_verbosity()) {
+      printf("Detected %d graphs without side effects.\n", num_const);
+      printf("Optimizes %d(SymConst) + %d(Sel) calls to const/pure functions.\n",
+	       ctx.n_calls_removed_SymConst, ctx.n_calls_removed_Sel);
+    }
+  }
+  else {
+    if (get_firm_verbosity()) {
+      printf("No graphs without side effects detected\n");
+    }
+  }
+}  /* optimize_funccalls */