Shader_IR: clean up AST handling and add documentation.

master
Fernando Sahmkow 2019-09-23 08:15:31 +07:00 committed by FernandoS27
parent 5ea740beb5
commit 7c756baa77
1 changed files with 6 additions and 2 deletions

@ -432,6 +432,12 @@ void ASTManager::InsertReturn(Expr condition, bool kills) {
program->nodes.PushBack(node); program->nodes.PushBack(node);
} }
// The decompile algorithm is based on
// "Taming control flow: A structured approach to eliminating goto statements"
// by AM Erosa, LJ Hendren 1994. In general, the idea is to get gotos to be
// on the same structured level as the label which they jump to. This is done,
// through outward/inward movements and lifting. Once they are at the same
// level, you can enclose them in an "if" structure or a "do-while" structure.
void ASTManager::Decompile() { void ASTManager::Decompile() {
auto it = gotos.begin(); auto it = gotos.begin();
while (it != gotos.end()) { while (it != gotos.end()) {
@ -656,11 +662,9 @@ void ASTManager::EncloseIfThen(ASTNode goto_node, ASTNode label) {
sub_zipper->Init(goto_node, if_node); sub_zipper->Init(goto_node, if_node);
zipper.InsertAfter(if_node, prev); zipper.InsertAfter(if_node, prev);
sub_zipper->Remove(goto_node); sub_zipper->Remove(goto_node);
// ShowCurrentState("After IfThen Enclose");
} }
void ASTManager::MoveOutward(ASTNode goto_node) { void ASTManager::MoveOutward(ASTNode goto_node) {
// ShowCurrentState("Before MoveOutward");
ASTZipper& zipper = goto_node->GetManager(); ASTZipper& zipper = goto_node->GetManager();
const ASTNode parent = goto_node->GetParent(); const ASTNode parent = goto_node->GetParent();
ASTZipper& zipper2 = parent->GetManager(); ASTZipper& zipper2 = parent->GetManager();