+
/* Copyright (C) 1998 - 2000 by Universitaet Karlsruhe
** All rights reserved.
**
** irgmod: ir graph modification
*/
+# include "irnode_t.h"
+# include "irgraph_t.h"
# include "irgmod.h"
-# include "iropt.h"
-
-/* ir_node * */
-/* arg_access (ir_mode *mode, long proj) */
-/* { */
-/* return new_r_Proj (current_ir_graph, current_ir_graph->start, */
-/* current_ir_graph->args, mode, proj); */
-/* } */
-
-
-/* these two functions are used in phi_merge, but defined in ircons.c */
-inline ir_node * get_r_value_internal (ir_node *block,
- int pos, ir_mode *mode);
-inline ir_node * new_r_Phi_in (ir_graph *irg, ir_node *block, ir_mode *mode,
- ir_node **in, int ins);
-
-/** This function computes the predecessors for a real Phi node, and then
- allocates and returns this node. The routine called to allocate the
- node might optimize it away and return a real value, or even a pointer
- to a deallocated Phi node on top of the obstack!
- This function is called with an in-array of proper size. **/
-static inline ir_node *
-phi_merge (ir_node *block, int pos, ir_mode *mode, ir_node **nin, int ins)
-{
- ir_node *prevBlock, *res;
- int i;
-
- /* This loop goes to all predecessor blocks of the block the Phi node is in
- and there finds the operands of the Phi node by calling get_r_value_internal. */
- for (i = 1; i <= ins; ++i) {
- assert (block->in[i]);
- prevBlock = block->in[i]->in[0]; /* go past control flow op to prev block */
- assert (prevBlock);
- nin[i-1] = get_r_value_internal (prevBlock, pos, mode);
- }
-
- /* After collecting all predecessors into the array nin a new Phi node
- with these predecessors is created. This constructor contains an
- optimization: If all predecessors of the Phi node are identical it
- returns the only operand instead of a new Phi node. If the value
- passes two different control flow edges without being defined, and
- this is the second path treated, a pointer to the node that will be
- allocated for the first path (recurstion) is returned. We already
- know the address of this node, as it is the next node to be allocated
- and will be placed on top of the obstack. (The obstack is a _stack_!) */
- res = new_r_Phi_in (current_ir_graph, block, mode, nin, ins);
-
- /* Now we now the value "pos" and can enter it in the array with
- all known local variables. Attention: this might be a pointer to
- a node, that later will be allocated!!! See new_r_Phi_in.
- If this is called in mature, after some set_value in the same block,
- the proper value must not be overwritten:
- The call order
- get_value (makes Phi0, put's it into graph_arr)
- set_value (overwrites Phi0 in graph_arr)
- mature_block (upgrades Phi0, puts it again into graph_arr, overwriting
- the proper value.)
- fails. */
- if (!block->attr.block.graph_arr[pos]) {
- block->attr.block.graph_arr[pos] = res;
- } else {
- // printf(" value already computed by %s\n",
- // id_to_str(block->attr.block.graph_arr[pos]->op->name));
- }
-
- return res;
-}
-
-
-/* this function is used in get_r_value_internal, but defined in ircons.c */
-inline ir_node * new_r_Phi0 (ir_graph *irg, ir_node *block, ir_mode *mode);
-
-
-/* This function returns the last definition of a variable. In case
- this variable was last defined in a previous block, Phi nodes are
- inserted. If the part of the firm graph containing the definition
- is not yet constructed, a dummy Phi node is returned. */
-inline ir_node *
-get_r_value_internal (ir_node *block, int pos, ir_mode *mode)
-{
- ir_node *res;
- /* There are 4 cases to treat.
-
- 1. The block is not mature and we visit it the first time. We can not
- create a proper Phi node, therefore a Phi0, i.e., a Phi without
- predecessors is returned. This node is added to the linked list (field
- "link") of the containing block to be completed when this block is
- matured. (Comlpletion will add a new Phi and turn the Phi0 into a Id
- node.)
-
- 2. The value is already known in this block, graph_arr[pos] is set and we
- visit the block the first time. We can return the value without
- creating any new nodes.
-
- 3. The block is mature and we visit it the first time. A Phi node needs
- to be created (phi_merge). If the Phi is not needed, as all it's
- operands are the same value reaching the block through different
- paths, it's optimizes away and the value itself is returned.
-
- 4. The block is mature, and we visit it the second time. Now two
- subcases are possible:
- * The value was computed completely the last time we were here.
- This is the case if there is no loop. We can return the proper value.
- * The recursion that visited this node and set the flag did not
- return yet. We are computing a value in a loop and need to
- break the recursion without knowing the result yet.
- There is no simple check for the second subcase. Therefore we check
- for a second visit and treat all such cases as the second subcase.
- Anyways, the basic situation is the same: we reached a block
- on two paths without finding a definition of the value: No Phi
- nodes are needed on both paths.
- We return this information "Two paths, no Phi needed" by a very tricky
- implementation that relies on the fact that an obstack is a stack and
- will return a node with the same address on different allocations.
- Look also at phi_merge and get_r_phi_in to understand this.
- */
-
- /* case 4 -- already visited. */
- if (block->visit == ir_visited) return NULL;
-
- /* visited the first time */
- block->visit = ir_visited;
-
- /* Get the local valid value */
- res = block->attr.block.graph_arr[pos];
-
- /* case 2 -- If the value is actually computed, return it. */
- if (res) { return res;};
-
- if (block->attr.block.matured) { /* case 3 */
-
- /* The Phi has the same amount of ins as the corresponding block. */
- int ins = get_irn_arity(block); // ARR_LEN (block->in)-1;
- ir_node **nin;
- NEW_ARR_A (ir_node *, nin, ins);
-
- /* Phi merge collects the predecessors and then creates a node. */
- res = phi_merge (block, pos, mode, nin, ins);
-
- } else { /* case 1 */
- /* The block is not mature, we don't know how many in's are needed. A Phi
- with zero predecessors is created. Such a Phi node is called Phi0
- node. (There is also an obsolete Phi0 opcode.) The Phi0 is then added
- to the list of Phi0 nodes in this block to be matured by mature_block
- later.
- The Phi0 has to remember the pos of it's internal value. If the real Phi
- is computed, pos is used to update the array with the local values. */
-
- res = new_r_Phi0 (current_ir_graph, block, mode);
- res->attr.phi0_pos = pos;
- res->link = block->link;
- block->link = res;
- }
-
- /* If we get here, the frontend missed a use-before-definition error */
- if (!res) {
- /* Error Message */
- printf("Error: no value set\n");
- assert (mode->code >= irm_f && mode->code <= irm_p);
- res = new_r_Const (current_ir_graph, block, mode,
- tarval_mode_null[mode->code]);
- }
-
- /* The local valid value is available now. */
- block->attr.block.graph_arr[pos] = res;
-
- return res;
-}
-
-
-/* add an adge to a jmp node */
-void
-add_in_edge (ir_node *block, ir_node *jmp)
-{
- if (block->attr.block.matured) {
- printf("Error: Block already matured!\n");
- }
- else {
- assert (jmp != NULL);
- ARR_APP1 (ir_node *, block->in, jmp);
- }
-}
-
-
-/****************************/
-/* parameter administration */
-
-/* get a value from the parameter array from the current block by its index */
-ir_node *
-get_value (int pos, ir_mode *mode)
-{
- ++ir_visited;
- return get_r_value_internal (current_ir_graph->current_block, pos + 1, mode);
-}
-
-
-/* set a value at position pos in the parameter array from the current block */
-inline void
-set_value (int pos, ir_node *value)
-{
- current_ir_graph->current_block->attr.block.graph_arr[pos + 1] = value;
-}
-
-
-/* get the current store */
-inline ir_node *
-get_store (void)
-{
- /* GL: one could call get_value instead */
- ++ir_visited;
- return get_r_value_internal (current_ir_graph->current_block, 0, mode_M);
-}
-
-
-/* set the current store */
-inline void
-set_store (ir_node *store)
-{
- /* GL: one could call set_value instead */
- current_ir_graph->current_block->attr.block.graph_arr[0] = store;
-}
-
-/** Finalize a Block node, when all control flows are known. */
-/** Acceptable parameters are only Block nodes. */
-void
-mature_block (ir_node *block)
-{
-
- int ins;
- ir_node *n, **nin;
- ir_node *next;
-
- assert (get_irn_opcode(block) == iro_Block);
-
- if (!get_Block_matured(block)) {
-
- /* turn the dynamic in-array into a static one. */
- ins = ARR_LEN (block->in)-1;
- NEW_ARR_A (ir_node *, nin, ins);
-
- /* GL, 7.2.2000. seems to be not complete. added this: but does'nt work.*
- memcpy (nin, block->in, sizeof (ir_node *) * ins);
- block->in = nin;
- */
-
- /* Traverse a chain of Phi nodes attached to this block and mature these, too. **/
- for (n = block->link; n; n=next) {
- ir_visited++;
- next = n->link;
- exchange (n, phi_merge (block, n->attr.phi0_pos, n->mode, nin, ins));
- }
-
- block->attr.block.matured = 1;
-
- block = optimize_in_place(block);
- ir_vrfy(block);
- }
-
-}
-
-/* changing the current block */
-void
-switch_block (ir_node *target)
-{
- current_ir_graph->current_block = target;
-}
-
+# include "array.h"
+/* Turns a node into a "useless" Tuple. The Tuple just forms a tuple
+ from several inputs.
+ This is useful if a node returning a tuple is removed, but the Projs
+ extracting values from the tuple are not available. */
void
turn_into_tuple (ir_node *node, int arity)
{
if (get_irn_arity(node) == arity) {
/* keep old array */
} else {
- /* allocate new array, remove old one. */
- /* !!!??? free old in_array */
+ /* Allocate new array, don't free old in_array, it's on the obstack. */
+ ir_node *block = get_nodes_Block(node);
node->in = NEW_ARR_D (ir_node *, current_ir_graph->obst, arity+1);
+ set_nodes_Block(node, block);
}
}
-
-
/* Insert irnode `new' in place of irnode `old'
Since `new' may be bigger than `old' replace `old'
by an op_Id which is smaller than everything */
projects / libfirm / blobdiff