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authorBrian Paul <brianp@vmware.com>2009-06-18 17:08:10 -0600
committerBrian Paul <brianp@vmware.com>2009-06-26 13:16:32 -0600
commitaba93643be09589318cfde33556d872b1cd9ea75 (patch)
treed6fce77e440d30dc4dd8e862bbbe7f3f48c052ad /src/mesa/shader
parent7e0eaca201c0a5678752e9d3de6f699ff8281f75 (diff)
glsl: implement continue->break translation for do-while loops
Diffstat (limited to 'src/mesa/shader')
-rw-r--r--src/mesa/shader/slang/slang_codegen.c234
1 files changed, 219 insertions, 15 deletions
diff --git a/src/mesa/shader/slang/slang_codegen.c b/src/mesa/shader/slang/slang_codegen.c
index 55a47b336d..5f40ddda20 100644
--- a/src/mesa/shader/slang/slang_codegen.c
+++ b/src/mesa/shader/slang/slang_codegen.c
@@ -326,6 +326,17 @@ sampler_to_texture_index(const slang_type_specifier_type type)
}
+/** helper to build a SLANG_OPER_IDENTIFIER node */
+static void
+slang_operation_identifier(slang_operation *oper,
+ slang_assemble_ctx *A,
+ const char *name)
+{
+ oper->type = SLANG_OPER_IDENTIFIER;
+ oper->a_id = slang_atom_pool_atom(A->atoms, name);
+}
+
+
#define SWIZZLE_ZWWW MAKE_SWIZZLE4(SWIZZLE_Z, SWIZZLE_W, SWIZZLE_W, SWIZZLE_W)
/**
@@ -2399,6 +2410,174 @@ _slang_gen_while(slang_assemble_ctx * A, const 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.
+ *
+ * Before:
+ *
+ * do {
+ * A;
+ * if (IFCOND)
+ * continue;
+ * B;
+ * break;
+ * C;
+ * } while (LOOPCOND);
+ *
+ * After:
+ *
+ * {
+ * bool _notBreakFlag = 1;
+ * do {
+ * do {
+ * A;
+ * if (IFCOND) {
+ * break; // was continue
+ * }
+ * B;
+ * _notBreakFlag = 0; // was
+ * break; // break
+ * C;
+ * } while (0)
+ * } while (_notBreakFlag && LOOPCOND);
+ * }
+ */
+static slang_ir_node *
+_slang_gen_do_without_continue(slang_assemble_ctx *A, slang_operation *oper)
+{
+ slang_operation *top;
+ slang_operation *innerBody;
+
+ assert(oper->type == SLANG_OPER_DO);
+
+ top = slang_operation_new(1);
+ top->type = SLANG_OPER_BLOCK_NEW_SCOPE;
+ top->locals->outer_scope = oper->locals->outer_scope;
+ slang_operation_add_children(top, 2);
+
+ /* declare: bool _notBreakFlag = true */
+ {
+ slang_operation *condDecl = slang_oper_child(top, 0);
+ slang_variable *var;
+
+ condDecl->type = SLANG_OPER_VARIABLE_DECL;
+ var = slang_variable_scope_grow(top->locals);
+ slang_fully_specified_type_construct(&var->type);
+ var->type.specifier.type = SLANG_SPEC_BOOL;
+ var->a_name = slang_atom_pool_atom(A->atoms, "_notBreakFlag");
+ condDecl->a_id = var->a_name;
+ var->initializer = slang_operation_new(1);
+ slang_operation_literal_bool(var->initializer, GL_TRUE);
+ }
+
+ /* build outer do-loop: do { ... } 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);
+ }
+ }
+
+ /* _notBreakFlag && LOOPCOND */
+ {
+ slang_operation *cond = slang_oper_child(outerDo, 1);
+ cond->type = SLANG_OPER_LOGICALAND;
+ slang_operation_add_children(cond, 2);
+ {
+ slang_operation *notBreak = slang_oper_child(cond, 0);
+ slang_operation_identifier(notBreak, A, "_notBreakFlag");
+ }
+ {
+ slang_operation *origCond = slang_oper_child(cond, 1);
+ slang_operation_copy(origCond, slang_oper_child(oper, 1));
+ }
+ }
+ }
+
+ /* Finally, in innerBody,
+ * replace "break" with "_notBreakFlag = 0; break"
+ * replace "continue" with "break"
+ */
+ replace_break_and_cont(A, innerBody);
+
+ slang_print_tree(top, 0);
+
+ return _slang_gen_operation(A, top);
+}
+
+
+/**
* Generate IR tree for a do-while loop using high-level LOOP, IF instructions.
*/
static slang_ir_node *
@@ -2413,6 +2592,15 @@ _slang_gen_do(slang_assemble_ctx * A, const slang_operation *oper)
slang_ir_node *prevLoop, *loop;
GLboolean isConst, constTrue;
+ if (!A->EmitContReturn) {
+ /* We don't want to emit CONT instructions. If this do-loop has
+ * a continue, translate it away.
+ */
+ if (_slang_find_node_type((slang_operation *) oper, SLANG_OPER_CONTINUE)) {
+ return _slang_gen_do_without_continue(A, (slang_operation *) oper);
+ }
+ }
+
/* type-check expression */
if (!_slang_is_boolean(A, &oper->children[1])) {
slang_info_log_error(A->log, "scalar/boolean expression expected for 'do/while'");
@@ -2670,6 +2858,34 @@ _slang_unroll_for_loop(slang_assemble_ctx * A, const slang_operation *oper)
/**
+ * Replace 'continue' statement with 'break' inside a for-loop.
+ * This is a recursive helper function used by _slang_gen_for_without_continue().
+ */
+static void
+replace_continue_with_break(slang_assemble_ctx *A, slang_operation *oper)
+{
+ switch (oper->type) {
+ case SLANG_OPER_CONTINUE:
+ 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_continue_with_break(A, slang_oper_child(oper, i));
+ }
+ }
+ }
+}
+
+
+/**
* Transform a for-loop so that continue statements are converted to breaks.
* Then do normal IR code generation.
*
@@ -2727,8 +2943,7 @@ _slang_gen_for_without_continue(slang_assemble_ctx *A, slang_operation *oper)
var->a_name = slang_atom_pool_atom(A->atoms, "_condFlag");
condDecl->a_id = var->a_name;
var->initializer = slang_operation_new(1);
- var->initializer->type = SLANG_OPER_LITERAL_BOOL;
- var->initializer->literal[0] = 1.0;
+ slang_operation_literal_bool(var->initializer, GL_TRUE);
}
/* build outer loop: for (INIT; _condFlag; ) { */
@@ -2793,19 +3008,8 @@ _slang_gen_for_without_continue(slang_assemble_ctx *A, slang_operation *oper)
slang_oper_child(oper, 2));
}
- /* finally, replace "continue" with "break" in inner for-loop */
- {
- slang_operation *body = slang_oper_child(innerFor, 3);
- while (1) {
- slang_operation *op =_slang_find_node_type(body, SLANG_OPER_CONTINUE);
- if (op) {
- op->type = SLANG_OPER_BREAK;
- }
- else {
- break;
- }
- }
- }
+ /* finally, replace "continue" with "break" in the inner for-loop */
+ replace_continue_with_break(A, slang_oper_child(innerFor, 3));
}
return _slang_gen_operation(A, top);