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authorLinus Torvalds <torvalds@ppc970.osdl.org>2004-08-03 13:19:56 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-07 21:02:34 -0700
commit2862612260c2c111884c03a5349f124d434304d3 (patch)
tree659ac3b7bfd5fccdd10188f51550d2b63a508c12
parent3027e1c365f4001ddb8a203b5a3a0e7132fd43cc (diff)
downloadsparse-dev-2862612260c2c111884c03a5349f124d434304d3.tar.gz
Start infrastructure for more dynamic register allocation.
Instead of using fixed register names, we keep track of busy registers, and allocate them as needed. Also changed EXPR_SELECT to actually use this.
Diffstat
-rw-r--r--compile-i386.c126
1 files changed, 112 insertions, 14 deletions
diff --git a/compile-i386.c b/compile-i386.c
index 3888a9db..1220dd08 100644
--- a/compile-i386.c
+++ b/compile-i386.c
@@ -39,6 +39,7 @@
#include "expression.h"
#include "target.h"
#include "compile.h"
+#include "bitmap.h"
struct textbuf {
unsigned int len; /* does NOT include terminating null */
@@ -77,6 +78,8 @@ enum storage_type {
struct reg_info {
const char *name;
+ const unsigned char aliases[12];
+#define own_regno aliases[0]
};
struct storage {
@@ -85,6 +88,7 @@ struct storage {
/* STOR_REG */
struct reg_info *reg;
+ struct symbol *ctype;
union {
/* STOR_PSEUDO */
@@ -161,6 +165,15 @@ struct function *current_func = NULL;
struct textbuf *unit_post_text = NULL;
static const char *current_section;
+static void emit_move(struct storage *src, struct storage *dest,
+ struct symbol *ctype, const char *comment);
+static int type_is_signed(struct symbol *sym);
+static struct storage *x86_address_gen(struct expression *expr);
+static struct storage *x86_symbol_expr(struct symbol *sym);
+static void x86_symbol(struct symbol *sym);
+static struct storage *x86_statement(struct statement *stmt);
+static struct storage *x86_expression(struct expression *expr);
+
enum registers {
NOREG,
AL, DL, CL, BL, AH, DH, CH, BH, // 8-bit
@@ -169,7 +182,10 @@ enum registers {
EAX_EDX, ECX_EBX, ESI_EDI, // 64-bit
};
-#define REGINFO(nr, str, aliases...) [nr] = { .name = str }
+/* This works on regno's, reg_info's and hardreg_storage's */
+#define byte_reg(reg) ((reg) - 16)
+
+#define REGINFO(nr, str, conflicts...) [nr] = { .name = str, .aliases = { nr , conflicts } }
static struct reg_info reg_info_table[] = {
REGINFO( AL, "%al", AX, EAX, EAX_EDX),
@@ -222,15 +238,92 @@ static struct storage hardreg_storage_table[] = {
#define REG_AL (&hardreg_storage_table[AL])
#define REG_AX (&hardreg_storage_table[AX])
-static void emit_move(struct storage *src, struct storage *dest,
- struct symbol *ctype, const char *comment);
-static int type_is_signed(struct symbol *sym);
-static struct storage *x86_address_gen(struct expression *expr);
-static struct storage *x86_symbol_expr(struct symbol *sym);
-static void x86_symbol(struct symbol *sym);
-static struct storage *x86_statement(struct statement *stmt);
-static struct storage *x86_expression(struct expression *expr);
+DECLARE_BITMAP(regs_in_use, 256);
+
+struct storage * get_hardreg(struct storage *reg)
+{
+ struct reg_info *info = reg->reg;
+ const unsigned char *aliases;
+ int regno;
+
+ aliases = info->aliases;
+ while ((regno = *aliases++) != NOREG) {
+ if (test_and_set_bit(regno, regs_in_use))
+ goto busy;
+ }
+ return reg;
+busy:
+ fprintf(stderr, "register %s is busy\n", info->name);
+ if (regno + reg_info_table != info)
+ fprintf(stderr, " conflicts with %s\n", reg_info_table[regno].name);
+ exit(1);
+}
+
+void put_reg(struct storage *reg)
+{
+ struct reg_info *info = reg->reg;
+ const unsigned char *aliases;
+ int regno;
+
+ aliases = info->aliases;
+ while ((regno = *aliases++) != NOREG) {
+ if (!test_and_clear_bit(regno, regs_in_use))
+ goto free;
+ }
+ return;
+free:
+ fprintf(stderr, "freeing already free'd register %s\n", reg_info_table[regno].name);
+}
+
+struct regclass {
+ const char *name;
+ const unsigned char regs[30];
+};
+
+struct regclass regclass_8 = { "8-bit", { AL, DL, CL, BL, AH, DH, CH, BH }};
+struct regclass regclass_16 = { "16-bit", { AX, DX, CX, BX, SI, DI, BP }};
+struct regclass regclass_32 = { "32-bit", { EAX, EDX, ECX, EBX, ESI, EDI, EBP }};
+
+struct regclass regclass_32_8 = { "32-bit bytes", { EAX, EDX, ECX, EBX }};
+
+static int register_busy(int regno)
+{
+ if (!test_bit(regno, regs_in_use)) {
+ struct reg_info *info = reg_info_table + regno;
+ const unsigned char *regs = info->aliases+1;
+
+ while ((regno = *regs) != NOREG) {
+ regs++;
+ if (test_bit(regno, regs_in_use))
+ goto busy;
+ }
+ return 0;
+ }
+busy:
+ return 1;
+}
+
+struct storage *get_reg(struct regclass *class)
+{
+ const unsigned char *regs = class->regs;
+ int regno;
+
+ while ((regno = *regs) != NOREG) {
+ regs++;
+ if (register_busy(regno))
+ continue;
+ return get_hardreg(hardreg_storage_table + regno);
+ }
+ fprintf(stderr, "Ran out of %s registers\n", class->name);
+ exit(1);
+}
+struct storage *get_reg_value(struct storage *value)
+{
+ struct storage *reg = get_reg(&regclass_32);
+ emit_move(value, reg, value->ctype, "reload register");
+ return reg;
+}
static struct storage *temp_from_bits(unsigned int bit_size)
{
@@ -1038,6 +1131,7 @@ static struct storage *emit_compare(struct expression *expr)
{
struct storage *left = x86_expression(expr->left);
struct storage *right = x86_expression(expr->right);
+ struct storage *reg1, *reg2;
struct storage *new, *val;
const char *opname = NULL;
unsigned int right_bits = expr->right->ctype->bit_size;
@@ -1067,20 +1161,24 @@ static struct storage *emit_compare(struct expression *expr)
/* init EDX to 0 */
val = new_storage(STOR_VALUE);
val->flags = STOR_WANTS_FREE;
- emit_move(val, REG_EDX, NULL, NULL);
+
+ reg1 = get_reg(&regclass_32_8);
+ emit_move(val, reg1, NULL, NULL);
/* move op1 into EAX */
- emit_move(left, REG_EAX, expr->left->ctype, NULL);
+ reg2 = get_reg_value(left);
/* perform comparison, RHS (op1, right) and LHS (op2, EAX) */
- insn(opbits("cmp", right_bits), right, REG_EAX, NULL);
+ insn(opbits("cmp", right_bits), right, reg2, NULL);
+ put_reg(reg2);
/* store result of operation, 0 or 1, in DL using SETcc */
- insn(opname, REG_DL, NULL, NULL);
+ insn(opname, byte_reg(reg1), NULL, NULL);
/* finally, store the result (DL) in a new pseudo / stack slot */
new = stack_alloc(4);
- emit_move(REG_EDX, new, NULL, "end EXPR_COMPARE");
+ emit_move(reg1, new, NULL, "end EXPR_COMPARE");
+ put_reg(reg1);
return new;
}
generated by cgit 1.2.3-korg (git 2.43.0) at 2026-03-01 21:21:19 +0000