d0p1/ack
1
0
Fork 0
Code Issues Pull requests Packages Projects Releases Wiki Activity

Introduce sequence points before store instructions to prevent loads from the

Browse source 
same address being delayed until after the store (at which point they'll return
the wrong value).
This commit is contained in:
David Given 2017-01-07 13:17:39 +01:00
parent 0da248dced
commit 7710c76d56
1 changed files with 27 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

27
mach/proto/mcg/treebuilder.c
View file

@ -119,6 +119,25 @@ static struct ir* appendir(struct ir* ir)
return ir;
}
static void sequence_point(void)
{
int i;
/* Ensures that any partially-evaluated expressions on the stack are executed right
* now. This typically needs to happen before store operations, to prevents loads of
* the same address being delayed until after the store (at which point they'll
* return incorrect values).
*/
assert(current_bb != NULL);
for (i=0; i<stackptr; i++)
{
struct ir* ir = stack[i];
array_appendu(&current_bb->irs, ir);
}
}
static void materialise_stack(void)
{
int i;
@ -229,6 +248,8 @@ static struct ir* store(int size, struct ir* address, int offset, struct ir* val
{
int opcode;
sequence_point();
if (size == 1)
{
opcode = IR_STOREB;
@ -475,6 +496,7 @@ static void insn_simple(int opcode)
case op_sim:
{
sequence_point();
appendir(
new_ir2(
(EM_wordsize == 2) ? IR_STORE : IR_STOREH, EM_wordsize,
@ -1497,6 +1519,7 @@ static void insn_lvalue(int opcode, const char* label, arith offset)
break;
case op_ste:
sequence_point();
appendir(
new_ir2(
IR_STORE, EM_wordsize,
@ -1507,6 +1530,7 @@ static void insn_lvalue(int opcode, const char* label, arith offset)
break;
case op_sde:
sequence_point();
appendir(
new_ir2(
IR_STORE, EM_wordsize*2,
@ -1517,6 +1541,7 @@ static void insn_lvalue(int opcode, const char* label, arith offset)
break;
case op_zre:
sequence_point();
appendir(
new_ir2(
IR_STORE, EM_wordsize,
@ -1527,6 +1552,7 @@ static void insn_lvalue(int opcode, const char* label, arith offset)
break;
case op_ine:
sequence_point();
appendir(
new_ir2(
IR_STORE, EM_wordsize,
@ -1544,6 +1570,7 @@ static void insn_lvalue(int opcode, const char* label, arith offset)
break;
case op_dee:
sequence_point();
appendir(
new_ir2(
IR_STORE, EM_wordsize,