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From-SVN: r1572
This commit is contained in:
Richard Stallman 1992-07-12 18:10:29 +00:00
parent 10f07067b5
commit 467456d054
1 changed files with 131 additions and 0 deletions
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131
gcc/function.c
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@ -3507,6 +3507,137 @@ round_trampoline_addr (tramp)
return tramp;
}
/* The functions identify_blocks and reorder_blocks provide a way to
reorder the tree of BLOCK nodes, for optimizers that reshuffle or
duplicate portions of the RTL code. Call identify_blocks before
changing the RTL, and call reorder_blocks after. */
static int all_blocks ();
static tree blocks_nreverse ();
/* Put all this function's BLOCK nodes into a vector, and return it.
Also store in each NOTE for the beginning or end of a block
the index of that block in the vector.
The arguments are TOP_BLOCK, the top-level block of the function,
and INSNS, the insn chain of the function. */
tree *
identify_blocks (top_block, insns)
tree top_block;
rtx insns;
{
int n_blocks = all_blocks (top_block, 0);
tree *block_vector = (tree *) alloca (n_blocks * sizeof (tree));
int *block_stack = (int *) alloca (n_blocks * sizeof (int));
int depth = 0;
int next_block_number = 0;
int current_block_number = 0;
rtx insn;
all_blocks (top_block, block_vector);
for (insn = insns; insn; insn = NEXT_INSN (insn))
if (GET_CODE (insn) == NOTE)
{
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG)
{
block_stack[depth++] = current_block_number;
current_block_number = next_block_number;
SET_NOTE_BLOCK_NUMBER (insn, next_block_number++);
}
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END)
{
current_block_number = block_stack[--depth];
SET_NOTE_BLOCK_NUMBER (insn, current_block_number);
}
}
return block_vector;
}
/* Given BLOCK_VECTOR which was returned by identify_blocks,
and a revised instruction chain, rebuild the tree structure
of BLOCK nodes to correspond to the new order of RTL.
Returns the current top-level block. */
tree
reorder_blocks (block_vector, insns)
tree *block_vector;
rtx insns;
{
tree current_block = block_vector[0];
rtx insn;
for (insn = insns; insn; insn = NEXT_INSN (insn))
if (GET_CODE (insn) == NOTE)
{
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG)
{
tree block = block_vector[NOTE_BLOCK_NUMBER (insn)];
/* If we have seen this block before, copy it. */
if (TREE_ASM_WRITTEN (block))
block = copy_node (block);
else
BLOCK_SUBBLOCKS (block) = 0;
TREE_ASM_WRITTEN (block) = 1;
BLOCK_SUPERCONTEXT (block) = current_block;
BLOCK_CHAIN (block) = BLOCK_SUBBLOCKS (current_block);
BLOCK_SUBBLOCKS (current_block) = block;
current_block = block;
SET_NOTE_BLOCK_NUMBER (insn, 0);
}
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END)
{
BLOCK_SUBBLOCKS (current_block)
= blocks_nreverse (BLOCK_SUBBLOCKS (current_block));
current_block = BLOCK_SUPERCONTEXT (current_block);
SET_NOTE_BLOCK_NUMBER (insn, 0);
}
}
return current_block;
}
/* Reverse the order of elements in the chain T of blocks,
and return the new head of the chain (old last element). */
static tree
blocks_nreverse (t)
tree t;
{
register tree prev = 0, decl, next;
for (decl = t; decl; decl = next)
{
next = BLOCK_CHAIN (decl);
BLOCK_CHAIN (decl) = prev;
prev = decl;
}
return prev;
}
/* Count the subblocks of BLOCK, and list them all into the vector VECTOR.
Also clear TREE_ASM_WRITTEN in all blocks. */
static int
all_blocks (block, vector)
tree block;
tree *vector;
{
int n_blocks = 1;
tree subblocks;
TREE_ASM_WRITTEN (block) = 0;
/* Record this block. */
vector[n_blocks++] = block;
/* Record the subblocks, and their subblocks. */
for (subblocks = BLOCK_SUBBLOCKS (block);
subblocks; subblocks = BLOCK_CHAIN (subblocks))
n_blocks += all_blocks (subblocks, vector + n_blocks);
return n_blocks;
}
/* Generate RTL for the start of the function SUBR (a FUNCTION_DECL tree node)
and initialize static variables for generating RTL for the statements
of the function. */