Refactor the cfg and dominance stuff to make it a lot nicer.

This commit is contained in:
David Given 2016-10-06 21:34:21 +02:00
parent 7f901aa4d0
commit ee93389c5f
10 changed files with 258 additions and 204 deletions

View file

@ -1,123 +0,0 @@
#include "mcg.h"
struct array postorder;
struct array preorder;
struct pmap dominators;
static void recursively_walk_blocks(struct basicblock* bb);
static void recursively_walk_graph(struct basicblock* bb)
{
static ARRAYOF(struct basicblock) pending;
int i;
if (array_contains(&postorder, bb) || array_contains(&pending, bb))
return;
array_appendu(&preorder, bb);
array_appendu(&pending, bb);
i = 0;
for (i=0; i<bb->nexts.count; i++)
recursively_walk_graph(bb->nexts.item[i]);
array_remove(&pending, bb);
bb->order = postorder.count;
array_appendu(&postorder, bb);
}
static void walk_graph_postorder(struct basicblock* entry)
{
int i;
preorder.count = 0;
postorder.count = 0;
recursively_walk_graph(entry);
for (i=0; i<postorder.count; i++)
{
tracef('D', "D: postorder: %s\n",
((struct basicblock*)postorder.item[i])->name);
}
}
static struct basicblock* intersect(struct basicblock* p1, struct basicblock* p2)
{
while (p1 != p2)
{
while (p1->order < p2->order)
p1 = pmap_get(&dominators, p1);
while (p2->order < p1->order)
p2 = pmap_get(&dominators, p2);
}
return p1;
}
void calculate_dominance_graph(struct procedure* proc)
{
/* This is the algorithm described here:
*
* Cooper, Keith D., Timothy J. Harvey, and Ken Kennedy.
* "A simple, fast dominance algorithm."
* Software Practice & Experience 4.1-10 (2001): 1-8.
*
* https://www.cs.rice.edu/~keith/EMBED/dom.pdf
*/
int i, j;
bool changed;
struct basicblock* entry = proc->blocks.item[0];
entry = proc->blocks.item[0];
walk_graph_postorder(entry);
assert(postorder.count == proc->blocks.count);
dominators.count = 0;
/* The entry block dominates itself. */
pmap_put(&dominators, entry, entry);
do
{
changed = false;
for (i = postorder.count-2; i >= 0; i--)
{
struct basicblock* b = postorder.item[i];
struct basicblock* new_idom = NULL;
for (j=0; j<b->prevs.count; j++)
{
struct basicblock* p = b->prevs.item[j];
/* Skip unprocessed blocks. */
if (!pmap_get(&dominators, p))
continue;
if (!new_idom)
new_idom = p;
else if (pmap_get(&dominators, p))
new_idom = intersect(p, new_idom);
}
if (pmap_get(&dominators, b) != new_idom)
{
pmap_put(&dominators, b, new_idom);
changed = true;
}
}
}
while (changed);
for (i=0; i<dominators.count; i++)
{
tracef('D', "D: domination: %s -> %s\n",
((struct basicblock*)dominators.item[i].left)->name,
((struct basicblock*)dominators.item[i].right)->name);
}
}
/* vim: set sw=4 ts=4 expandtab : */

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@ -1,13 +0,0 @@
#ifndef DOMINANCE_H
#define DOMINANCE_H
extern struct array postorder;
extern struct array preorder;
extern struct pmap dominators;
extern void calculate_dominance_graph(struct procedure* proc);
#endif
/* vim: set sw=4 ts=4 expandtab : */

208
mach/proto/mcg/graph.c Normal file
View file

@ -0,0 +1,208 @@
#include "mcg.h"
struct graph_data cfg;
struct dominance_data dominance;
static ARRAYOF(struct basicblock) pending;
static bool collect_outputs_cb(struct ir* ir, void* user)
{
struct basicblock* caller = user;
if (ir->opcode == IR_BLOCK)
{
array_appendu(&caller->nexts, ir->u.bvalue);
array_appendu(&ir->u.bvalue->prevs, caller);
}
return false;
}
static void update_block_pointers_from_ir(struct procedure* proc)
{
int i, j;
for (i=0; i<proc->blocks.count; i++)
{
struct basicblock* bb = proc->blocks.item[i];
bb->prevs.count = bb->nexts.count = 0;
}
for (i=0; i<proc->blocks.count; i++)
{
struct basicblock* bb = proc->blocks.item[i];
for (j=0; j<bb->irs.count; j++)
ir_walk(bb->irs.item[j], collect_outputs_cb, bb);
}
for (i=0; i<proc->blocks.count; i++)
{
struct basicblock* bb = proc->blocks.item[i];
for (j=0; j<bb->nexts.count; j++)
{
tracef('D', "D: cfg graph %s -> %s\n",
bb->name,
bb->nexts.item[j]->name);
}
}
}
static void recursively_walk_cfg_graph(struct basicblock* bb)
{
int i;
if (array_contains(&cfg.postorder, bb) || array_contains(&pending, bb))
return;
array_appendu(&cfg.preorder, bb);
array_appendu(&pending, bb);
for (i=0; i<bb->nexts.count; i++)
recursively_walk_cfg_graph(bb->nexts.item[i]);
array_remove(&pending, bb);
bb->order = cfg.postorder.count;
array_appendu(&cfg.postorder, bb);
}
static void walk_cfg_graph(void)
{
int i;
cfg.preorder.count = 0;
cfg.postorder.count = 0;
pending.count = 0;
recursively_walk_cfg_graph(cfg.entry);
for (i=0; i<cfg.preorder.count; i++)
{
tracef('G', "G: cfg preorder: %s\n",
cfg.preorder.item[i]->name);
}
}
static struct basicblock* intersect(struct basicblock* p1, struct basicblock* p2)
{
while (p1 != p2)
{
while (p1->order < p2->order)
p1 = pmap_get(&dominance.graph, p1);
while (p2->order < p1->order)
p2 = pmap_get(&dominance.graph, p2);
}
return p1;
}
static void calculate_dominance_graph(void)
{
/* This is the algorithm described here:
*
* Cooper, Keith D., Timothy J. Harvey, and Ken Kennedy.
* "A simple, fast dominance algorithm."
* Software Practice & Experience 4.1-10 (2001): 1-8.
*
* https://www.cs.rice.edu/~keith/EMBED/dom.pdf
*/
int i, j;
bool changed;
dominance.graph.count = 0;
/* The entry block dominates itself. */
pmap_put(&dominance.graph, cfg.entry, cfg.entry);
do
{
changed = false;
for (i = cfg.postorder.count-2; i >= 0; i--)
{
struct basicblock* b = cfg.postorder.item[i];
struct basicblock* new_idom = NULL;
for (j=0; j<b->prevs.count; j++)
{
struct basicblock* p = b->prevs.item[j];
/* Skip unprocessed blocks. */
if (!pmap_get(&dominance.graph, p))
continue;
if (!new_idom)
new_idom = p;
else if (pmap_get(&dominance.graph, p))
new_idom = intersect(p, new_idom);
}
if (pmap_get(&dominance.graph, b) != new_idom)
{
pmap_put(&dominance.graph, b, new_idom);
changed = true;
}
}
}
while (changed);
for (i=0; i<dominance.graph.count; i++)
{
tracef('G', "G: dominance graph: %s -> %s\n",
dominance.graph.item[i].right->name,
dominance.graph.item[i].left->name);
}
}
static void recursively_walk_dominance_graph(struct basicblock* bb)
{
int i;
if (array_contains(&dominance.postorder, bb) || array_contains(&pending, bb))
return;
array_appendu(&dominance.preorder, bb);
array_appendu(&pending, bb);
for (i=0; i<dominance.graph.count; i++)
if (dominance.graph.item[i].right == bb)
recursively_walk_dominance_graph(dominance.graph.item[i].left);
array_remove(&pending, bb);
array_appendu(&dominance.postorder, bb);
}
static void walk_dominance_graph(void)
{
int i;
dominance.preorder.count = 0;
dominance.postorder.count = 0;
pending.count = 0;
recursively_walk_dominance_graph(cfg.entry);
for (i=0; i<dominance.preorder.count; i++)
{
tracef('G', "G: dominance preorder: %s\n",
dominance.preorder.item[i]->name);
}
}
void update_graph_data(struct procedure* proc)
{
cfg.entry = proc->blocks.item[0];
update_block_pointers_from_ir(proc);
walk_cfg_graph();
assert(cfg.postorder.count == proc->blocks.count);
assert(cfg.preorder.count == proc->blocks.count);
calculate_dominance_graph();
walk_dominance_graph();
assert(dominance.postorder.count == dominance.graph.count);
assert(dominance.preorder.count == dominance.graph.count);
}
/* vim: set sw=4 ts=4 expandtab : */

26
mach/proto/mcg/graph.h Normal file
View file

@ -0,0 +1,26 @@
#ifndef GRAPH_H
#define GRAPH_H
struct graph_data
{
struct basicblock* entry;
ARRAYOF(struct basicblock) preorder;
ARRAYOF(struct basicblock) postorder;
};
struct dominance_data
{
PMAPOF(struct basicblock, struct basicblock) graph;
ARRAYOF(struct basicblock) preorder;
ARRAYOF(struct basicblock) postorder;
};
extern struct graph_data cfg;
extern struct dominance_data dominance;
extern void update_graph_data(struct procedure* proc);
#endif
/* vim: set sw=4 ts=4 expandtab : */

View file

@ -27,7 +27,7 @@
#include "reg.h"
#include "basicblock.h"
#include "procedure.h"
#include "dominance.h"
#include "graph.h"
extern char em_pseu[][4];
extern char em_mnem[][4];

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@ -1,6 +1,5 @@
#include "mcg.h"
static PMAPOF(struct basicblock, struct basicblock) graph;
static ARRAYOF(struct ir) pops;
static ARRAYOF(struct ir) pushes;

View file

@ -11,10 +11,10 @@ static void recursively_walk_dominance_graph(struct basicblock* bb)
/* Skip the entry block (which is its own dominator). */
for (i=1; i<dominators.count; i++)
for (i=1; i<dominance.graph.count; i++)
{
struct basicblock* left = dominators.item[i].left;
struct basicblock* right = dominators.item[i].right;
struct basicblock* left = dominance.graph.item[i].left;
struct basicblock* right = dominance.graph.item[i].right;
if (right == bb)
recursively_walk_dominance_graph(left);
}
@ -22,10 +22,8 @@ static void recursively_walk_dominance_graph(struct basicblock* bb)
void pass_register_allocator(struct procedure* proc)
{
calculate_dominance_graph(proc);
blocks.count = 0;
recursively_walk_dominance_graph(proc->blocks.item[0]);
recursively_walk_dominance_graph(cfg.entry);
assert(blocks.count == proc->blocks.count);
}

View file

@ -36,12 +36,14 @@ static void split_edge(struct basicblock* source, struct basicblock* sink)
struct rewrite_params rwp;
struct basicblock* bb = bb_get(NULL);
array_append(&bb->irs,
struct ir* jump =
new_ir1(
IR_JUMP, 0,
new_bbir(sink)
)
);
);
jump->root = jump->left->root = jump;
array_append(&bb->irs, jump);
rwp.find = sink;
rwp.replace = bb;

View file

@ -1,6 +1,5 @@
#include "mcg.h"
static struct basicblock* entry;
static PMAPOF(struct basicblock, struct basicblock) dominancefrontiers;
static struct local* current_local;
@ -24,10 +23,10 @@ static void calculate_dominance_frontier_graph(void)
dominancefrontiers.count = 0;
for (i=0; i<postorder.count; i++)
for (i=0; i<cfg.postorder.count; i++)
{
struct basicblock* b = postorder.item[i];
struct basicblock* dominator = pmap_get(&dominators, b);
struct basicblock* b = cfg.postorder.item[i];
struct basicblock* dominator = pmap_get(&dominance.graph, b);
if (b->prevs.count >= 2)
{
for (j=0; j<b->prevs.count; j++)
@ -38,7 +37,7 @@ static void calculate_dominance_frontier_graph(void)
tracef('S', "S: %s is in %s's dominance frontier\n",
b->name, runner->name);
pmap_add(&dominancefrontiers, runner, b);
runner = pmap_get(&dominators, runner);
runner = pmap_get(&dominance.graph, runner);
}
}
}
@ -158,7 +157,7 @@ static void ssa_convert(void)
ir->left->root = ir;
ir->right->root = ir;
ir->right->left->root = ir;
array_insert(&entry->irs, ir, 0);
array_insert(&cfg.entry->irs, ir, 0);
}
defining.count = 0;
@ -166,9 +165,9 @@ static void ssa_convert(void)
/* Find everwhere where the variable is *defined*. */
for (i=0; i<postorder.count; i++)
for (i=0; i<cfg.postorder.count; i++)
{
struct basicblock* bb = postorder.item[i];
struct basicblock* bb = cfg.postorder.item[i];
for (j=0; j<bb->irs.count; j++)
{
struct ir* ir = bb->irs.item[j];
@ -210,15 +209,13 @@ static void ssa_convert(void)
definitions.count = 0;
rewritten.count = 0;
recursively_rewrite_tree(entry);
recursively_rewrite_tree(cfg.entry);
}
void pass_convert_locals_to_ssa(struct procedure* proc)
{
int i;
entry = proc->blocks.item[0];
calculate_dominance_graph(proc);
calculate_dominance_frontier_graph();
for (i=0; i<proc->locals.count; i++)

View file

@ -48,66 +48,26 @@ void procedure_compile(struct procedure* proc)
pass_eliminate_trivial_blocks(proc);
pass_remove_dead_blocks(proc);
procedure_update_bb_graph(proc);
update_graph_data(proc);
/* Passes from here on can't alter the BB graph without also updating prevs
* and nexts. */
* and nexts (and then calling update_graph_data()). */
print_blocks('2', proc);
pass_convert_stack_ops(proc);
print_blocks('3', proc);
pass_convert_locals_to_ssa(proc);
print_blocks('4', proc);
pass_split_critical_edges(proc);
print_blocks('5', proc);
pass_promote_float_ops(proc);
print_blocks('5', proc);
pass_split_critical_edges(proc);
print_blocks('6', proc);
update_graph_data(proc);
pass_instruction_selector(proc);
pass_register_allocator(proc);
}
static bool collect_outputs_cb(struct ir* ir, void* user)
{
struct basicblock* caller = user;
if (ir->opcode == IR_BLOCK)
{
array_appendu(&caller->nexts, ir->u.bvalue);
array_appendu(&ir->u.bvalue->prevs, caller);
}
return false;
}
void procedure_update_bb_graph(struct procedure* proc)
{
int i, j;
for (i=0; i<proc->blocks.count; i++)
{
struct basicblock* bb = proc->blocks.item[i];
bb->prevs.count = bb->nexts.count = 0;
}
for (i=0; i<proc->blocks.count; i++)
{
struct basicblock* bb = proc->blocks.item[i];
for (j=0; j<bb->irs.count; j++)
ir_walk(bb->irs.item[j], collect_outputs_cb, bb);
}
for (i=0; i<proc->blocks.count; i++)
{
struct basicblock* bb = proc->blocks.item[i];
for (j=0; j<bb->nexts.count; j++)
{
tracef('G', "G: graph %s -> %s\n",
bb->name,
bb->nexts.item[j]->name);
}
}
}
/* vim: set sw=4 ts=4 expandtab : */