From 7c756baa777cd27b319c1a397bd45270d2ffe041 Mon Sep 17 00:00:00 2001 From: Fernando Sahmkow Date: Mon, 23 Sep 2019 08:15:31 -0400 Subject: Shader_IR: clean up AST handling and add documentation. --- src/video_core/shader/ast.cpp | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/src/video_core/shader/ast.cpp b/src/video_core/shader/ast.cpp index 54f0240e1..fc440526f 100644 --- a/src/video_core/shader/ast.cpp +++ b/src/video_core/shader/ast.cpp @@ -432,6 +432,12 @@ void ASTManager::InsertReturn(Expr condition, bool kills) { 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() { auto it = gotos.begin(); while (it != gotos.end()) { @@ -656,11 +662,9 @@ void ASTManager::EncloseIfThen(ASTNode goto_node, ASTNode label) { sub_zipper->Init(goto_node, if_node); zipper.InsertAfter(if_node, prev); sub_zipper->Remove(goto_node); - // ShowCurrentState("After IfThen Enclose"); } void ASTManager::MoveOutward(ASTNode goto_node) { - // ShowCurrentState("Before MoveOutward"); ASTZipper& zipper = goto_node->GetManager(); const ASTNode parent = goto_node->GetParent(); ASTZipper& zipper2 = parent->GetManager(); -- cgit v1.2.3