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fix instruction offset calculation in powerpc.cpp

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The previous code did not take into account any padding embedded in a
basic block due to inline jump tables, which led to invalid code
generation in large methods
This commit is contained in:
Joel Dice 2011-05-11 19:50:45 -06:00
parent 195bafa9b3
commit b76cbbfa56
1 changed files with 46 additions and 30 deletions
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76
src/powerpc.cpp
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@ -196,7 +196,7 @@ class MyBlock: public Assembler::Block {
MyBlock(Context* context, unsigned offset):
context(context), next(0), jumpOffsetHead(0), jumpOffsetTail(0),
lastJumpOffsetTail(0), jumpEventHead(0), jumpEventTail(0),
lastEventOffset(0), offset(offset), start(~0), size(0)
lastEventOffset(0), offset(offset), start(~0), size(0), resolved(false)
{ }
virtual unsigned resolve(unsigned start, Assembler::Block* next) {
@ -205,6 +205,8 @@ class MyBlock: public Assembler::Block {
::resolve(this);
this->resolved = true;
return start + size + padding(this, size);
}
@ -219,6 +221,7 @@ class MyBlock: public Assembler::Block {
unsigned offset;
unsigned start;
unsigned size;
bool resolved;
};
class Task;
@ -326,13 +329,14 @@ class Offset: public Promise {
{ }
virtual bool resolved() {
return block->start != static_cast<unsigned>(~0);
return block->resolved;
}
virtual int64_t value() {
assert(c, resolved());
return block->start + (offset - block->offset);
unsigned o = offset - block->offset;
return block->start + padding(block, o) + o;
}
Context* c;
@ -495,38 +499,24 @@ appendJumpEvent(Context* c, MyBlock* b, unsigned offset, JumpOffset* head,
b->jumpEventTail = e;
}
bool
needJump(MyBlock* b)
{
return b->next or (not bounded(2, 16, b->size));
}
unsigned
padding(MyBlock* b, unsigned offset)
{
unsigned total = 0;
for (JumpEvent** e = &(b->jumpEventHead); *e;) {
if ((*e)->offset <= offset) {
for (JumpOffset** o = &((*e)->jumpOffsetHead); *o;) {
if ((*o)->task->promise->resolved()
and (*o)->task->instructionOffset->resolved())
{
int32_t v = reinterpret_cast<uint8_t*>((*o)->task->promise->value())
- (b->context->result + (*o)->task->instructionOffset->value());
if (bounded(2, 16, v)) {
// this conditional jump needs no indirection -- a direct
// jump will suffice
*o = (*o)->next;
continue;
}
}
for (JumpEvent* e = b->jumpEventHead; e; e = e->next) {
if (e->offset <= offset) {
for (JumpOffset* o = e->jumpOffsetHead; o; o = o->next) {
total += BytesPerWord;
o = &((*o)->next);
}
if ((*e)->jumpOffsetHead == 0) {
*e = (*e)->next;
} else {
if (b->next) {
total += BytesPerWord;
}
e = &((*e)->next);
if (needJump(b)) {
total += BytesPerWord;
}
} else {
break;
@ -541,6 +531,32 @@ resolve(MyBlock* b)
{
Context* c = b->context;
for (JumpEvent** e = &(b->jumpEventHead); *e;) {
for (JumpOffset** o = &((*e)->jumpOffsetHead); *o;) {
if ((*o)->task->promise->resolved()
and (*o)->task->instructionOffset->resolved())
{
int32_t v = reinterpret_cast<uint8_t*>((*o)->task->promise->value())
- (c->result + (*o)->task->instructionOffset->value());
if (bounded(2, 16, v)) {
// this conditional jump needs no indirection -- a direct
// jump will suffice
*o = (*o)->next;
continue;
}
}
o = &((*o)->next);
}
if ((*e)->jumpOffsetHead == 0) {
*e = (*e)->next;
} else {
e = &((*e)->next);
}
}
if (b->jumpOffsetHead) {
if (c->jumpOffsetTail) {
c->jumpOffsetTail->next = b->jumpOffsetHead;
@ -2680,7 +2696,7 @@ class MyAssembler: public Assembler {
uint8_t* address = dst + dstOffset + jumpTableSize;
if (b->next) {
if (needJump(b)) {
address += BytesPerWord;
}
@ -2691,7 +2707,7 @@ class MyAssembler: public Assembler {
assert(&c, jumpTableSize);
if (b->next) {
if (needJump(b)) {
write4(dst + dstOffset, ::b(jumpTableSize + BytesPerWord));
}