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glsl: implement _slang_gen_while_without_continue()

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This commit is contained in:
Brian Paul
2009-06-23 14:05:11 -06:00
parent 2102e301a7
commit 08025cd4a5
1 changed files with 117 additions and 84 deletions
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src/mesa/shader/slang/slang_codegen.c
+117 -84
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@@ -2411,14 +2411,102 @@ _slang_loop_contains_continue_or_break(const slang_operation *oper)
}
/**
* Replace 'break' and 'continue' statements inside a do and while loops.
* This is a recursive helper function used by
* _slang_gen_do/while_without_continue().
*/
static void
replace_break_and_cont(slang_assemble_ctx *A, slang_operation *oper)
{
switch (oper->type) {
case SLANG_OPER_BREAK:
/* replace 'break' with "_notBreakFlag = false; break" */
{
slang_operation *block = oper;
block->type = SLANG_OPER_BLOCK_NEW_SCOPE;
slang_operation_add_children(block, 2);
{
slang_operation *assign = slang_oper_child(block, 0);
assign->type = SLANG_OPER_ASSIGN;
slang_operation_add_children(assign, 2);
{
slang_operation *lhs = slang_oper_child(assign, 0);
slang_operation_identifier(lhs, A, "_notBreakFlag");
}
{
slang_operation *rhs = slang_oper_child(assign, 1);
slang_operation_literal_bool(rhs, GL_FALSE);
}
}
{
slang_operation *brk = slang_oper_child(block, 1);
brk->type = SLANG_OPER_BREAK;
assert(!brk->children);
}
}
break;
case SLANG_OPER_CONTINUE:
/* convert continue into a break */
oper->type = SLANG_OPER_BREAK;
break;
case SLANG_OPER_FOR:
case SLANG_OPER_DO:
case SLANG_OPER_WHILE:
/* stop upon finding a nested loop */
break;
default:
/* recurse */
{
GLuint i;
for (i = 0; i < oper->num_children; i++) {
replace_break_and_cont(A, slang_oper_child(oper, i));
}
}
}
}
/**
* Transform a while-loop so that continue statements are converted to breaks.
* Then do normal IR code generation.
*
* Before:
*
* while (LOOPCOND) {
* A;
* if (IFCOND)
* continue;
* B;
* break;
* C;
* }
*
* After:
*
* {
* bool _notBreakFlag = 1;
* while (_notBreakFlag && LOOPCOND) {
* do {
* A;
* if (IFCOND) {
* break; // was continue
* }
* B;
* _notBreakFlag = 0; // was
* break; // break
* C;
* } while (0)
* }
* }
*/
static slang_ir_node *
_slang_gen_while_without_continue(slang_assemble_ctx *A, slang_operation *oper)
{
#if 0
slang_operation *top;
slang_operation *innerBody;
assert(oper->type == SLANG_OPER_DO);
assert(oper->type == SLANG_OPER_WHILE);
top = slang_operation_new(1);
top->type = SLANG_OPER_BLOCK_NEW_SCOPE;
@@ -2440,33 +2528,15 @@ _slang_gen_while_without_continue(slang_assemble_ctx *A, slang_operation *oper)
slang_operation_literal_bool(var->initializer, GL_TRUE);
}
/* build outer do-loop: do { ... } while (_notBreakFlag && LOOPCOND) */
/* build outer while-loop: while (_notBreakFlag && LOOPCOND) { ... } */
{
slang_operation *outerDo = slang_oper_child(top, 1);
outerDo->type = SLANG_OPER_DO;
slang_operation_add_children(outerDo, 2);
/* inner do-loop */
{
slang_operation *innerDo = slang_oper_child(outerDo, 0);
innerDo->type = SLANG_OPER_DO;
slang_operation_add_children(innerDo, 2);
/* copy original do-loop body into inner do-loop's body */
innerBody = slang_oper_child(innerDo, 0);
slang_operation_copy(innerBody, slang_oper_child(oper, 0));
innerBody->locals->outer_scope = innerDo->locals;
/* inner do-loop's condition is constant/false */
{
slang_operation *constFalse = slang_oper_child(innerDo, 1);
slang_operation_literal_bool(constFalse, GL_FALSE);
}
}
slang_operation *outerWhile = slang_oper_child(top, 1);
outerWhile->type = SLANG_OPER_WHILE;
slang_operation_add_children(outerWhile, 2);
/* _notBreakFlag && LOOPCOND */
{
slang_operation *cond = slang_oper_child(outerDo, 1);
slang_operation *cond = slang_oper_child(outerWhile, 0);
cond->type = SLANG_OPER_LOGICALAND;
slang_operation_add_children(cond, 2);
{
@@ -2475,7 +2545,25 @@ _slang_gen_while_without_continue(slang_assemble_ctx *A, slang_operation *oper)
}
{
slang_operation *origCond = slang_oper_child(cond, 1);
slang_operation_copy(origCond, slang_oper_child(oper, 1));
slang_operation_copy(origCond, slang_oper_child(oper, 0));
}
}
/* inner loop */
{
slang_operation *innerDo = slang_oper_child(outerWhile, 1);
innerDo->type = SLANG_OPER_DO;
slang_operation_add_children(innerDo, 2);
/* copy original do-loop body into inner do-loop's body */
innerBody = slang_oper_child(innerDo, 0);
slang_operation_copy(innerBody, slang_oper_child(oper, 1));
innerBody->locals->outer_scope = innerDo->locals;
/* inner do-loop's condition is constant/false */
{
slang_operation *constFalse = slang_oper_child(innerDo, 1);
slang_operation_literal_bool(constFalse, GL_FALSE);
}
}
}
@@ -2486,10 +2574,10 @@ _slang_gen_while_without_continue(slang_assemble_ctx *A, slang_operation *oper)
*/
replace_break_and_cont(A, innerBody);
slang_print_tree(top, 0);
/*slang_print_tree(top, 0);*/
return _slang_gen_operation(A, top);
#endif
return NULL;
}
@@ -2569,61 +2657,6 @@ _slang_gen_while(slang_assemble_ctx * A, slang_operation *oper)
}
/**
* Replace 'break' and 'continue' statements inside a do-while loop.
* This is a recursive helper function used by _slang_gen_do_without_continue().
*/
static void
replace_break_and_cont(slang_assemble_ctx *A, slang_operation *oper)
{
switch (oper->type) {
case SLANG_OPER_BREAK:
/* replace 'break' with "_notBreakFlag = false; break" */
{
slang_operation *block = oper;
block->type = SLANG_OPER_BLOCK_NEW_SCOPE;
slang_operation_add_children(block, 2);
{
slang_operation *assign = slang_oper_child(block, 0);
assign->type = SLANG_OPER_ASSIGN;
slang_operation_add_children(assign, 2);
{
slang_operation *lhs = slang_oper_child(assign, 0);
slang_operation_identifier(lhs, A, "_notBreakFlag");
}
{
slang_operation *rhs = slang_oper_child(assign, 1);
slang_operation_literal_bool(rhs, GL_FALSE);
}
}
{
slang_operation *brk = slang_oper_child(block, 1);
brk->type = SLANG_OPER_BREAK;
assert(!brk->children);
}
}
break;
case SLANG_OPER_CONTINUE:
/* convert continue into a break */
oper->type = SLANG_OPER_BREAK;
break;
case SLANG_OPER_FOR:
case SLANG_OPER_DO:
case SLANG_OPER_WHILE:
/* stop upon finding a nested loop */
break;
default:
/* recurse */
{
GLuint i;
for (i = 0; i < oper->num_children; i++) {
replace_break_and_cont(A, slang_oper_child(oper, i));
}
}
}
}
/**
* Transform a do-while-loop so that continue statements are converted to breaks.
* Then do normal IR code generation.
@@ -2731,7 +2764,7 @@ _slang_gen_do_without_continue(slang_assemble_ctx *A, slang_operation *oper)
*/
replace_break_and_cont(A, innerBody);
slang_print_tree(top, 0);
/*slang_print_tree(top, 0);*/
return _slang_gen_operation(A, top);
}