From c17953978b16f82a3b2049f8b961275020c73dd0 Mon Sep 17 00:00:00 2001
From: Fernando Sahmkow <fsahmkow27@gmail.com>
Date: Thu, 27 Jun 2019 00:39:40 -0400
Subject: shader_ir: Initial Decompile Setup

---
 src/video_core/CMakeLists.txt | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'src/video_core/CMakeLists.txt')

diff --git a/src/video_core/CMakeLists.txt b/src/video_core/CMakeLists.txt
index e2f85c5f1..32049a2e7 100644
--- a/src/video_core/CMakeLists.txt
+++ b/src/video_core/CMakeLists.txt
@@ -105,9 +105,12 @@ add_library(video_core STATIC
     shader/decode/warp.cpp
     shader/decode/xmad.cpp
     shader/decode/other.cpp
+    shader/ast.cpp
+    shader/ast.h
     shader/control_flow.cpp
     shader/control_flow.h
     shader/decode.cpp
+    shader/expr.h
     shader/node_helper.cpp
     shader/node_helper.h
     shader/node.h
-- 
cgit v1.2.3


From 8be6e1c5221066a49b6ad27efbd20a999a7c16b3 Mon Sep 17 00:00:00 2001
From: Fernando Sahmkow <fsahmkow27@gmail.com>
Date: Fri, 28 Jun 2019 20:54:21 -0400
Subject: shader_ir: Corrections to outward movements and misc stuffs

---
 CMakeModules/GenerateSCMRev.cmake      |   4 +
 src/common/CMakeLists.txt              |   4 +
 src/video_core/CMakeLists.txt          |   1 +
 src/video_core/shader/ast.cpp          | 185 ++++++++++++++++++++++++---------
 src/video_core/shader/ast.h            |  53 ++++++++--
 src/video_core/shader/control_flow.cpp |  14 ++-
 src/video_core/shader/expr.cpp         |  75 +++++++++++++
 src/video_core/shader/expr.h           |  36 ++++++-
 8 files changed, 314 insertions(+), 58 deletions(-)
 create mode 100644 src/video_core/shader/expr.cpp

(limited to 'src/video_core/CMakeLists.txt')

diff --git a/CMakeModules/GenerateSCMRev.cmake b/CMakeModules/GenerateSCMRev.cmake
index a1ace89cb..d3ab22c08 100644
--- a/CMakeModules/GenerateSCMRev.cmake
+++ b/CMakeModules/GenerateSCMRev.cmake
@@ -83,9 +83,13 @@ set(HASH_FILES
     "${VIDEO_CORE}/shader/decode/video.cpp"
     "${VIDEO_CORE}/shader/decode/warp.cpp"
     "${VIDEO_CORE}/shader/decode/xmad.cpp"
+    "${VIDEO_CORE}/shader/ast.cpp"
+    "${VIDEO_CORE}/shader/ast.h"
     "${VIDEO_CORE}/shader/control_flow.cpp"
     "${VIDEO_CORE}/shader/control_flow.h"
     "${VIDEO_CORE}/shader/decode.cpp"
+    "${VIDEO_CORE}/shader/expr.cpp"
+    "${VIDEO_CORE}/shader/expr.h"
     "${VIDEO_CORE}/shader/node.h"
     "${VIDEO_CORE}/shader/node_helper.cpp"
     "${VIDEO_CORE}/shader/node_helper.h"
diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index dfed8b51d..afc5ff736 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -60,9 +60,13 @@ add_custom_command(OUTPUT scm_rev.cpp
       "${VIDEO_CORE}/shader/decode/video.cpp"
       "${VIDEO_CORE}/shader/decode/warp.cpp"
       "${VIDEO_CORE}/shader/decode/xmad.cpp"
+      "${VIDEO_CORE}/shader/ast.cpp"
+      "${VIDEO_CORE}/shader/ast.h"
       "${VIDEO_CORE}/shader/control_flow.cpp"
       "${VIDEO_CORE}/shader/control_flow.h"
       "${VIDEO_CORE}/shader/decode.cpp"
+      "${VIDEO_CORE}/shader/expr.cpp"
+      "${VIDEO_CORE}/shader/expr.h"
       "${VIDEO_CORE}/shader/node.h"
       "${VIDEO_CORE}/shader/node_helper.cpp"
       "${VIDEO_CORE}/shader/node_helper.h"
diff --git a/src/video_core/CMakeLists.txt b/src/video_core/CMakeLists.txt
index 32049a2e7..33fa88762 100644
--- a/src/video_core/CMakeLists.txt
+++ b/src/video_core/CMakeLists.txt
@@ -110,6 +110,7 @@ add_library(video_core STATIC
     shader/control_flow.cpp
     shader/control_flow.h
     shader/decode.cpp
+    shader/expr.cpp
     shader/expr.h
     shader/node_helper.cpp
     shader/node_helper.h
diff --git a/src/video_core/shader/ast.cpp b/src/video_core/shader/ast.cpp
index 56a1b29f3..d521a7b52 100644
--- a/src/video_core/shader/ast.cpp
+++ b/src/video_core/shader/ast.cpp
@@ -12,18 +12,22 @@
 namespace VideoCommon::Shader {
 
 ASTZipper::ASTZipper() = default;
-ASTZipper::ASTZipper(ASTNode new_first) : first{}, last{} {
+
+void ASTZipper::Init(ASTNode new_first, ASTNode parent) {
+    ASSERT(new_first->manager == nullptr);
     first = new_first;
     last = new_first;
     ASTNode current = first;
     while (current) {
         current->manager = this;
+        current->parent = parent;
         last = current;
         current = current->next;
     }
 }
 
 void ASTZipper::PushBack(ASTNode new_node) {
+    ASSERT(new_node->manager == nullptr);
     new_node->previous = last;
     if (last) {
         last->next = new_node;
@@ -37,38 +41,55 @@ void ASTZipper::PushBack(ASTNode new_node) {
 }
 
 void ASTZipper::PushFront(ASTNode new_node) {
+    ASSERT(new_node->manager == nullptr);
     new_node->previous.reset();
     new_node->next = first;
     if (first) {
-        first->previous = first;
+        first->previous = new_node;
     }
-    first = new_node;
-    if (!last) {
+    if (last == first) {
         last = new_node;
     }
+    first = new_node;
     new_node->manager = this;
 }
 
 void ASTZipper::InsertAfter(ASTNode new_node, ASTNode at_node) {
+    ASSERT(new_node->manager == nullptr);
     if (!at_node) {
         PushFront(new_node);
         return;
     }
+    ASTNode next = at_node->next;
+    if (next) {
+        next->previous = new_node;
+    }
     new_node->previous = at_node;
     if (at_node == last) {
         last = new_node;
     }
-    new_node->next = at_node->next;
+    new_node->next = next;
     at_node->next = new_node;
     new_node->manager = this;
 }
 
-void ASTZipper::SetParent(ASTNode new_parent) {
-    ASTNode current = first;
-    while (current) {
-        current->parent = new_parent;
-        current = current->next;
+void ASTZipper::InsertBefore(ASTNode new_node, ASTNode at_node) {
+    ASSERT(new_node->manager == nullptr);
+    if (!at_node) {
+        PushBack(new_node);
+        return;
     }
+    ASTNode previous = at_node->previous;
+    if (previous) {
+        previous->next = new_node;
+    }
+    new_node->next = at_node;
+    if (at_node == first) {
+        first = new_node;
+    }
+    new_node->previous = previous;
+    at_node->previous = new_node;
+    new_node->manager = this;
 }
 
 void ASTZipper::DetachTail(ASTNode node) {
@@ -80,11 +101,22 @@ void ASTZipper::DetachTail(ASTNode node) {
     }
 
     last = node->previous;
+    last->next.reset();
     node->previous.reset();
+    ASTNode current = node;
+    while (current) {
+        current->manager = nullptr;
+        current->parent.reset();
+        current = current->next;
+    }
 }
 
 void ASTZipper::DetachSegment(ASTNode start, ASTNode end) {
     ASSERT(start->manager == this && end->manager == this);
+    if (start == end) {
+        DetachSingle(start);
+        return;
+    }
     ASTNode prev = start->previous;
     ASTNode post = end->next;
     if (!prev) {
@@ -131,7 +163,6 @@ void ASTZipper::DetachSingle(ASTNode node) {
     node->parent.reset();
 }
 
-
 void ASTZipper::Remove(ASTNode node) {
     ASSERT(node->manager == this);
     ASTNode next = node->next;
@@ -178,12 +209,7 @@ public:
     }
 
     void operator()(ExprPredicate const& expr) {
-        u32 pred = static_cast<u32>(expr.predicate);
-        if (pred > 7) {
-            inner += "!";
-            pred -= 8;
-        }
-        inner += "P" + std::to_string(pred);
+        inner += "P" + std::to_string(expr.predicate);
     }
 
     void operator()(ExprCondCode const& expr) {
@@ -253,6 +279,10 @@ public:
                  ");\n";
     }
 
+    void operator()(ASTBlockDecoded& ast) {
+        inner += Ident() + "Block;\n";
+    }
+
     void operator()(ASTVarSet& ast) {
         ExprPrinter expr_parser{};
         std::visit(expr_parser, *ast.condition);
@@ -282,7 +312,7 @@ public:
             current = current->GetNext();
         }
         scope--;
-        inner += Ident() + "} while (" + expr_parser.GetResult() + ")\n";
+        inner += Ident() + "} while (" + expr_parser.GetResult() + ");\n";
     }
 
     void operator()(ASTReturn& ast) {
@@ -333,8 +363,6 @@ std::string ASTManager::Print() {
     return printer.GetResult();
 }
 
-#pragma optimize("", off)
-
 void ASTManager::Decompile() {
     auto it = gotos.begin();
     while (it != gotos.end()) {
@@ -348,11 +376,12 @@ void ASTManager::Decompile() {
         }
         if (DirectlyRelated(goto_node, label)) {
             u32 goto_level = goto_node->GetLevel();
-            u32 label_level = goto_node->GetLevel();
-            while (label_level > goto_level) {
+            u32 label_level = label->GetLevel();
+            while (label_level < goto_level) {
                 MoveOutward(goto_node);
-                goto_level++;
+                goto_level--;
             }
+            // TODO(Blinkhawk): Implement Lifting and Inward Movements
         }
         if (label->GetParent() == goto_node->GetParent()) {
             bool is_loop = false;
@@ -375,13 +404,11 @@ void ASTManager::Decompile() {
         }
         it++;
     }
-    /*
     for (ASTNode label : labels) {
         auto& manager = label->GetManager();
         manager.Remove(label);
     }
     labels.clear();
-    */
 }
 
 bool ASTManager::IndirectlyRelated(ASTNode first, ASTNode second) {
@@ -410,87 +437,149 @@ bool ASTManager::DirectlyRelated(ASTNode first, ASTNode second) {
         max = second;
     }
 
-    while (min_level < max_level) {
-        min_level++;
-        min = min->GetParent();
+    while (max_level > min_level) {
+        max_level--;
+        max = max->GetParent();
     }
 
     return (min->GetParent() == max->GetParent());
 }
 
+void ASTManager::ShowCurrentState(std::string state) {
+    LOG_CRITICAL(HW_GPU, "\nState {}:\n\n{}\n", state, Print());
+    SanityCheck();
+}
+
+void ASTManager::SanityCheck() {
+    for (auto label : labels) {
+        if (!label->GetParent()) {
+            LOG_CRITICAL(HW_GPU, "Sanity Check Failed");
+        }
+    }
+}
+
 void ASTManager::EncloseDoWhile(ASTNode goto_node, ASTNode label) {
+    // ShowCurrentState("Before DoWhile Enclose");
+    enclose_count++;
     ASTZipper& zipper = goto_node->GetManager();
     ASTNode loop_start = label->GetNext();
     if (loop_start == goto_node) {
         zipper.Remove(goto_node);
+        // ShowCurrentState("Ignore DoWhile Enclose");
         return;
     }
     ASTNode parent = label->GetParent();
     Expr condition = goto_node->GetGotoCondition();
     zipper.DetachSegment(loop_start, goto_node);
-    ASTNode do_while_node = ASTBase::Make<ASTDoWhile>(parent, condition, ASTZipper(loop_start));
-    zipper.InsertAfter(do_while_node, label);
+    ASTNode do_while_node = ASTBase::Make<ASTDoWhile>(parent, condition);
     ASTZipper* sub_zipper = do_while_node->GetSubNodes();
-    sub_zipper->SetParent(do_while_node);
+    sub_zipper->Init(loop_start, do_while_node);
+    zipper.InsertAfter(do_while_node, label);
     sub_zipper->Remove(goto_node);
+    // ShowCurrentState("After DoWhile Enclose");
 }
 
 void ASTManager::EncloseIfThen(ASTNode goto_node, ASTNode label) {
+    // ShowCurrentState("Before IfThen Enclose");
+    enclose_count++;
     ASTZipper& zipper = goto_node->GetManager();
     ASTNode if_end = label->GetPrevious();
     if (if_end == goto_node) {
         zipper.Remove(goto_node);
+        // ShowCurrentState("Ignore IfThen Enclose");
         return;
     }
     ASTNode prev = goto_node->GetPrevious();
-    ASTNode parent = label->GetParent();
     Expr condition = goto_node->GetGotoCondition();
-    Expr neg_condition = MakeExpr<ExprNot>(condition);
+    bool do_else = false;
+    if (prev->IsIfThen()) {
+        Expr if_condition = prev->GetIfCondition();
+        do_else = ExprAreEqual(if_condition, condition);
+    }
+    ASTNode parent = label->GetParent();
     zipper.DetachSegment(goto_node, if_end);
-    ASTNode if_node = ASTBase::Make<ASTIfThen>(parent, condition, ASTZipper(goto_node));
-    zipper.InsertAfter(if_node, prev);
+    ASTNode if_node;
+    if (do_else) {
+        if_node = ASTBase::Make<ASTIfElse>(parent);
+    } else {
+        Expr neg_condition = MakeExprNot(condition);
+        if_node = ASTBase::Make<ASTIfThen>(parent, neg_condition);
+    }
     ASTZipper* sub_zipper = if_node->GetSubNodes();
-    sub_zipper->SetParent(if_node);
+    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");
+    outward_count++;
     ASTZipper& zipper = goto_node->GetManager();
     ASTNode parent = goto_node->GetParent();
+    ASTZipper& zipper2 = parent->GetManager();
+    ASTNode grandpa = parent->GetParent();
     bool is_loop = parent->IsLoop();
-    bool is_if = parent->IsIfThen() || parent->IsIfElse();
+    bool is_else = parent->IsIfElse();
+    bool is_if = parent->IsIfThen();
 
     ASTNode prev = goto_node->GetPrevious();
+    ASTNode post = goto_node->GetNext();
 
     Expr condition = goto_node->GetGotoCondition();
-    u32 var_index = NewVariable();
-    Expr var_condition = MakeExpr<ExprVar>(var_index);
-    ASTNode var_node = ASTBase::Make<ASTVarSet>(parent, var_index, condition);
     zipper.DetachSingle(goto_node);
-    zipper.InsertAfter(var_node, prev);
-    goto_node->SetGotoCondition(var_condition);
     if (is_loop) {
+        u32 var_index = NewVariable();
+        Expr var_condition = MakeExpr<ExprVar>(var_index);
+        ASTNode var_node = ASTBase::Make<ASTVarSet>(parent, var_index, condition);
+        ASTNode var_node_init = ASTBase::Make<ASTVarSet>(parent, var_index, true_condition);
+        zipper2.InsertBefore(var_node_init, parent);
+        zipper.InsertAfter(var_node, prev);
+        goto_node->SetGotoCondition(var_condition);
         ASTNode break_node = ASTBase::Make<ASTBreak>(parent, var_condition);
         zipper.InsertAfter(break_node, var_node);
-    } else if (is_if) {
-        ASTNode post = var_node->GetNext();
+    } else if (is_if || is_else) {
         if (post) {
+            u32 var_index = NewVariable();
+            Expr var_condition = MakeExpr<ExprVar>(var_index);
+            ASTNode var_node = ASTBase::Make<ASTVarSet>(parent, var_index, condition);
+            ASTNode var_node_init = ASTBase::Make<ASTVarSet>(parent, var_index, true_condition);
+            if (is_if) {
+                zipper2.InsertBefore(var_node_init, parent);
+            } else {
+                zipper2.InsertBefore(var_node_init, parent->GetPrevious());
+            }
+            zipper.InsertAfter(var_node, prev);
+            goto_node->SetGotoCondition(var_condition);
             zipper.DetachTail(post);
-            ASTNode if_node = ASTBase::Make<ASTIfThen>(parent, var_condition, ASTZipper(post));
-            zipper.InsertAfter(if_node, var_node);
+            ASTNode if_node = ASTBase::Make<ASTIfThen>(parent, MakeExprNot(var_condition));
             ASTZipper* sub_zipper = if_node->GetSubNodes();
-            sub_zipper->SetParent(if_node);
+            sub_zipper->Init(post, if_node);
+            zipper.InsertAfter(if_node, var_node);
+        } else {
+            Expr if_condition;
+            if (is_if) {
+                if_condition = parent->GetIfCondition();
+            } else {
+                ASTNode if_node = parent->GetPrevious();
+                if_condition = MakeExprNot(if_node->GetIfCondition());
+            }
+            Expr new_condition = MakeExprAnd(if_condition, condition);
+            goto_node->SetGotoCondition(new_condition);
         }
     } else {
         UNREACHABLE();
     }
-    ASTZipper& zipper2 = parent->GetManager();
     ASTNode next = parent->GetNext();
     if (is_if && next && next->IsIfElse()) {
         zipper2.InsertAfter(goto_node, next);
+        goto_node->SetParent(grandpa);
+        // ShowCurrentState("After MoveOutward");
         return;
     }
     zipper2.InsertAfter(goto_node, parent);
+    goto_node->SetParent(grandpa);
+    // ShowCurrentState("After MoveOutward");
 }
 
 } // namespace VideoCommon::Shader
diff --git a/src/video_core/shader/ast.h b/src/video_core/shader/ast.h
index 22ac8884c..4276f66a9 100644
--- a/src/video_core/shader/ast.h
+++ b/src/video_core/shader/ast.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <functional>
 #include <list>
 #include <memory>
 #include <optional>
@@ -21,6 +22,7 @@ class ASTProgram;
 class ASTIfThen;
 class ASTIfElse;
 class ASTBlockEncoded;
+class ASTBlockDecoded;
 class ASTVarSet;
 class ASTGoto;
 class ASTLabel;
@@ -28,7 +30,7 @@ class ASTDoWhile;
 class ASTReturn;
 class ASTBreak;
 
-using ASTData = std::variant<ASTProgram, ASTIfThen, ASTIfElse, ASTBlockEncoded, ASTVarSet, ASTGoto,
+using ASTData = std::variant<ASTProgram, ASTIfThen, ASTIfElse, ASTBlockEncoded, ASTBlockDecoded, ASTVarSet, ASTGoto,
                              ASTLabel, ASTDoWhile, ASTReturn, ASTBreak>;
 
 using ASTNode = std::shared_ptr<ASTBase>;
@@ -43,7 +45,8 @@ enum class ASTZipperType : u32 {
 class ASTZipper final {
 public:
     ASTZipper();
-    ASTZipper(ASTNode first);
+
+    void Init(ASTNode first, ASTNode parent);
 
     ASTNode GetFirst() {
         return first;
@@ -56,7 +59,7 @@ public:
     void PushBack(ASTNode new_node);
     void PushFront(ASTNode new_node);
     void InsertAfter(ASTNode new_node, ASTNode at_node);
-    void SetParent(ASTNode new_parent);
+    void InsertBefore(ASTNode new_node, ASTNode at_node);
     void DetachTail(ASTNode node);
     void DetachSingle(ASTNode node);
     void DetachSegment(ASTNode start, ASTNode end);
@@ -74,14 +77,14 @@ public:
 
 class ASTIfThen {
 public:
-    ASTIfThen(Expr condition, ASTZipper nodes) : condition(condition), nodes{nodes} {}
+    ASTIfThen(Expr condition) : condition(condition), nodes{} {}
     Expr condition;
     ASTZipper nodes;
 };
 
 class ASTIfElse {
 public:
-    ASTIfElse(ASTZipper nodes) : nodes{nodes} {}
+    ASTIfElse() : nodes{} {}
     ASTZipper nodes;
 };
 
@@ -92,6 +95,12 @@ public:
     u32 end;
 };
 
+class ASTBlockDecoded {
+public:
+    ASTBlockDecoded(NodeBlock& new_nodes) : nodes(std::move(new_nodes)) {}
+    NodeBlock nodes;
+};
+
 class ASTVarSet {
 public:
     ASTVarSet(u32 index, Expr condition) : index{index}, condition{condition} {}
@@ -114,7 +123,7 @@ public:
 
 class ASTDoWhile {
 public:
-    ASTDoWhile(Expr condition, ASTZipper nodes) : condition(condition), nodes{nodes} {}
+    ASTDoWhile(Expr condition) : condition(condition), nodes{} {}
     Expr condition;
     ASTZipper nodes;
 };
@@ -132,6 +141,8 @@ public:
     Expr condition;
 };
 
+using TransformCallback = std::function<NodeBlock(u32 start, u32 end)>;
+
 class ASTBase {
 public:
     explicit ASTBase(ASTNode parent, ASTData data) : parent{parent}, data{data} {}
@@ -195,6 +206,14 @@ public:
         return nullptr;
     }
 
+    Expr GetIfCondition() const {
+        auto inner = std::get_if<ASTIfThen>(&data);
+        if (inner) {
+            return inner->condition;
+        }
+        return nullptr;
+    }
+
     void SetGotoCondition(Expr new_condition) {
         auto inner = std::get_if<ASTGoto>(&data);
         if (inner) {
@@ -210,6 +229,18 @@ public:
         return std::holds_alternative<ASTIfElse>(data);
     }
 
+    bool IsBlockEncoded() const {
+        return std::holds_alternative<ASTBlockEncoded>(data);
+    }
+
+    void TransformBlockEncoded(TransformCallback& callback) {
+        auto block = std::get_if<ASTBlockEncoded>(&data);
+        const u32 start = block->start;
+        const u32 end = block->end;
+        NodeBlock nodes = callback(start, end);
+        data = ASTBlockDecoded(nodes);
+    }
+
     bool IsLoop() const {
         return std::holds_alternative<ASTDoWhile>(data);
     }
@@ -245,6 +276,7 @@ public:
     explicit ASTManager() {
         main_node = ASTBase::Make<ASTProgram>(ASTNode{});
         program = std::get_if<ASTProgram>(main_node->GetInnerData());
+        true_condition = MakeExpr<ExprBoolean>(true);
     }
 
     void DeclareLabel(u32 address) {
@@ -283,7 +315,13 @@ public:
 
     void Decompile();
 
+    void ShowCurrentState(std::string state);
 
+    void SanityCheck();
+
+    bool IsFullyDecompiled() {
+        return gotos.size() == 0;
+    }
 
 private:
     bool IndirectlyRelated(ASTNode first, ASTNode second);
@@ -309,6 +347,9 @@ private:
     u32 variables{};
     ASTProgram* program;
     ASTNode main_node;
+    Expr true_condition;
+    u32 outward_count{};
+    u32 enclose_count{};
 };
 
 } // namespace VideoCommon::Shader
diff --git a/src/video_core/shader/control_flow.cpp b/src/video_core/shader/control_flow.cpp
index bea7f767c..7a21d870f 100644
--- a/src/video_core/shader/control_flow.cpp
+++ b/src/video_core/shader/control_flow.cpp
@@ -423,7 +423,16 @@ void InsertBranch(ASTManager& mm, const BlockBranchInfo& branch) {
             result = MakeExpr<ExprCondCode>(cond.cc);
         }
         if (cond.predicate != Pred::UnusedIndex) {
-            Expr extra = MakeExpr<ExprPredicate>(cond.predicate);
+            u32 pred = static_cast<u32>(cond.predicate);
+            bool negate;
+            if (pred > 7) {
+                negate = true;
+                pred -= 8;
+            }
+            Expr extra = MakeExpr<ExprPredicate>(pred);
+            if (negate) {
+                extra = MakeExpr<ExprNot>(extra);
+            }
             if (result) {
                 return MakeExpr<ExprAnd>(extra, result);
             }
@@ -460,8 +469,9 @@ void DecompileShader(CFGRebuildState& state) {
             InsertBranch(manager, block.branch);
         }
     }
+    //manager.ShowCurrentState("Before Decompiling");
     manager.Decompile();
-    LOG_CRITICAL(HW_GPU, "Decompiled Shader:\n{} \n", manager.Print());
+    //manager.ShowCurrentState("After Decompiling");
 }
 
 std::optional<ShaderCharacteristics> ScanFlow(const ProgramCode& program_code,
diff --git a/src/video_core/shader/expr.cpp b/src/video_core/shader/expr.cpp
new file mode 100644
index 000000000..ebce6339b
--- /dev/null
+++ b/src/video_core/shader/expr.cpp
@@ -0,0 +1,75 @@
+// Copyright 2019 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <variant>
+
+#include "video_core/shader/expr.h"
+
+namespace VideoCommon::Shader {
+
+bool ExprAnd::operator==(const ExprAnd& b) const {
+    return (*operand1 == *b.operand1) && (*operand2 == *b.operand2);
+}
+
+bool ExprOr::operator==(const ExprOr& b) const {
+    return (*operand1 == *b.operand1) && (*operand2 == *b.operand2);
+}
+
+bool ExprNot::operator==(const ExprNot& b) const {
+    return (*operand1 == *b.operand1);
+}
+
+bool ExprIsBoolean(Expr expr) {
+    return std::holds_alternative<ExprBoolean>(*expr);
+}
+
+bool ExprBooleanGet(Expr expr) {
+    return std::get_if<ExprBoolean>(expr.get())->value;
+}
+
+Expr MakeExprNot(Expr first) {
+    if (std::holds_alternative<ExprNot>(*first)) {
+        return std::get_if<ExprNot>(first.get())->operand1;
+    }
+    return MakeExpr<ExprNot>(first);
+}
+
+Expr MakeExprAnd(Expr first, Expr second) {
+    if (ExprIsBoolean(first)) {
+        return ExprBooleanGet(first) ? second : first;
+    }
+    if (ExprIsBoolean(second)) {
+        return ExprBooleanGet(second) ? first : second;
+    }
+    return MakeExpr<ExprAnd>(first, second);
+}
+
+Expr MakeExprOr(Expr first, Expr second) {
+    if (ExprIsBoolean(first)) {
+        return ExprBooleanGet(first) ? first : second;
+    }
+    if (ExprIsBoolean(second)) {
+        return ExprBooleanGet(second) ? second : first;
+    }
+    return MakeExpr<ExprOr>(first, second);
+}
+
+bool ExprAreEqual(Expr first, Expr second) {
+    return (*first) == (*second);
+}
+
+bool ExprAreOpposite(Expr first, Expr second) {
+    if (std::holds_alternative<ExprNot>(*first)) {
+        return ExprAreEqual(std::get_if<ExprNot>(first.get())->operand1, second);
+    }
+    if (std::holds_alternative<ExprNot>(*second)) {
+        return ExprAreEqual(std::get_if<ExprNot>(second.get())->operand1, first);
+    }
+    return false;
+}
+
+} // namespace VideoCommon::Shader
diff --git a/src/video_core/shader/expr.h b/src/video_core/shader/expr.h
index 94678f09a..f012f6fcf 100644
--- a/src/video_core/shader/expr.h
+++ b/src/video_core/shader/expr.h
@@ -30,6 +30,8 @@ class ExprAnd final {
 public:
     ExprAnd(Expr a, Expr b) : operand1{a}, operand2{b} {}
 
+    bool operator==(const ExprAnd& b) const;
+
     Expr operand1;
     Expr operand2;
 };
@@ -38,6 +40,8 @@ class ExprOr final {
 public:
     ExprOr(Expr a, Expr b) : operand1{a}, operand2{b} {}
 
+    bool operator==(const ExprOr& b) const;
+
     Expr operand1;
     Expr operand2;
 };
@@ -46,6 +50,8 @@ class ExprNot final {
 public:
     ExprNot(Expr a) : operand1{a} {}
 
+    bool operator==(const ExprNot& b) const;
+
     Expr operand1;
 };
 
@@ -53,20 +59,32 @@ class ExprVar final {
 public:
     ExprVar(u32 index) : var_index{index} {}
 
+    bool operator==(const ExprVar& b) const {
+        return var_index == b.var_index;
+    }
+
     u32 var_index;
 };
 
 class ExprPredicate final {
 public:
-    ExprPredicate(Pred predicate) : predicate{predicate} {}
+    ExprPredicate(u32 predicate) : predicate{predicate} {}
+
+    bool operator==(const ExprPredicate& b) const {
+        return predicate == b.predicate;
+    }
 
-    Pred predicate;
+    u32 predicate;
 };
 
 class ExprCondCode final {
 public:
     ExprCondCode(ConditionCode cc) : cc{cc} {}
 
+    bool operator==(const ExprCondCode& b) const {
+        return cc == b.cc;
+    }
+
     ConditionCode cc;
 };
 
@@ -74,6 +92,10 @@ class ExprBoolean final {
 public:
     ExprBoolean(bool val) : value{val} {}
 
+    bool operator==(const ExprBoolean& b) const {
+        return value == b.value;
+    }
+
     bool value;
 };
 
@@ -83,4 +105,14 @@ Expr MakeExpr(Args&&... args) {
     return std::make_shared<ExprData>(T(std::forward<Args>(args)...));
 }
 
+bool ExprAreEqual(Expr first, Expr second);
+
+bool ExprAreOpposite(Expr first, Expr second);
+
+Expr MakeExprNot(Expr first);
+
+Expr MakeExprAnd(Expr first, Expr second);
+
+Expr MakeExprOr(Expr first, Expr second);
+
 } // namespace VideoCommon::Shader
-- 
cgit v1.2.3


From 47e4f6a52c5eb34916e2c1f4c876e6e8624e3840 Mon Sep 17 00:00:00 2001
From: Fernando Sahmkow <fsahmkow27@gmail.com>
Date: Fri, 16 Aug 2019 16:25:02 -0400
Subject: Shader_Ir: Refactor Decompilation process and allow multiple
 decompilation modes.

---
 CMakeModules/GenerateSCMRev.cmake                  |  2 +
 src/common/CMakeLists.txt                          |  2 +
 src/video_core/CMakeLists.txt                      |  2 +
 .../renderer_opengl/gl_shader_decompiler.cpp       |  8 +-
 src/video_core/renderer_opengl/gl_shader_gen.cpp   | 25 ++++--
 src/video_core/shader/ast.cpp                      | 98 ++++++++++++++++++++--
 src/video_core/shader/ast.h                        | 20 ++++-
 src/video_core/shader/compiler_settings.cpp        | 26 ++++++
 src/video_core/shader/compiler_settings.h          | 25 ++++++
 src/video_core/shader/control_flow.cpp             | 92 +++++++++++++-------
 src/video_core/shader/control_flow.h               | 10 ++-
 src/video_core/shader/decode.cpp                   | 86 +++++++++++++------
 src/video_core/shader/decode/other.cpp             |  8 +-
 src/video_core/shader/shader_ir.cpp                |  6 +-
 src/video_core/shader/shader_ir.h                  | 10 ++-
 15 files changed, 338 insertions(+), 82 deletions(-)
 create mode 100644 src/video_core/shader/compiler_settings.cpp
 create mode 100644 src/video_core/shader/compiler_settings.h

(limited to 'src/video_core/CMakeLists.txt')

diff --git a/CMakeModules/GenerateSCMRev.cmake b/CMakeModules/GenerateSCMRev.cmake
index d3ab22c08..09eabe2c7 100644
--- a/CMakeModules/GenerateSCMRev.cmake
+++ b/CMakeModules/GenerateSCMRev.cmake
@@ -87,6 +87,8 @@ set(HASH_FILES
     "${VIDEO_CORE}/shader/ast.h"
     "${VIDEO_CORE}/shader/control_flow.cpp"
     "${VIDEO_CORE}/shader/control_flow.h"
+    "${VIDEO_CORE}/shader/compiler_settings.cpp"
+    "${VIDEO_CORE}/shader/compiler_settings.h"
     "${VIDEO_CORE}/shader/decode.cpp"
     "${VIDEO_CORE}/shader/expr.cpp"
     "${VIDEO_CORE}/shader/expr.h"
diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index afc5ff736..0ed96c0d4 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -64,6 +64,8 @@ add_custom_command(OUTPUT scm_rev.cpp
       "${VIDEO_CORE}/shader/ast.h"
       "${VIDEO_CORE}/shader/control_flow.cpp"
       "${VIDEO_CORE}/shader/control_flow.h"
+      "${VIDEO_CORE}/shader/compiler_settings.cpp"
+      "${VIDEO_CORE}/shader/compiler_settings.h"
       "${VIDEO_CORE}/shader/decode.cpp"
       "${VIDEO_CORE}/shader/expr.cpp"
       "${VIDEO_CORE}/shader/expr.h"
diff --git a/src/video_core/CMakeLists.txt b/src/video_core/CMakeLists.txt
index 33fa88762..eaa694ff8 100644
--- a/src/video_core/CMakeLists.txt
+++ b/src/video_core/CMakeLists.txt
@@ -109,6 +109,8 @@ add_library(video_core STATIC
     shader/ast.h
     shader/control_flow.cpp
     shader/control_flow.h
+    shader/compiler_settings.cpp
+    shader/compiler_settings.h
     shader/decode.cpp
     shader/expr.cpp
     shader/expr.h
diff --git a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
index 2955c6abf..b8c3442bc 100644
--- a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
+++ b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
@@ -352,9 +352,11 @@ public:
         // TODO(Subv): Figure out the actual depth of the flow stack, for now it seems
         // unlikely that shaders will use 20 nested SSYs and PBKs.
         constexpr u32 FLOW_STACK_SIZE = 20;
-        for (const auto stack : std::array{MetaStackClass::Ssy, MetaStackClass::Pbk}) {
-            code.AddLine("uint {}[{}];", FlowStackName(stack), FLOW_STACK_SIZE);
-            code.AddLine("uint {} = 0u;", FlowStackTopName(stack));
+        if (!ir.IsFlowStackDisabled()) {
+            for (const auto stack : std::array{MetaStackClass::Ssy, MetaStackClass::Pbk}) {
+                code.AddLine("uint {}[{}];", FlowStackName(stack), FLOW_STACK_SIZE);
+                code.AddLine("uint {} = 0u;", FlowStackTopName(stack));
+            }
         }
 
         code.AddLine("while (true) {{");
diff --git a/src/video_core/renderer_opengl/gl_shader_gen.cpp b/src/video_core/renderer_opengl/gl_shader_gen.cpp
index 3a8d9e1da..72a49ebdc 100644
--- a/src/video_core/renderer_opengl/gl_shader_gen.cpp
+++ b/src/video_core/renderer_opengl/gl_shader_gen.cpp
@@ -11,6 +11,8 @@
 namespace OpenGL::GLShader {
 
 using Tegra::Engines::Maxwell3D;
+using VideoCommon::Shader::CompileDepth;
+using VideoCommon::Shader::CompilerSettings;
 using VideoCommon::Shader::ProgramCode;
 using VideoCommon::Shader::ShaderIR;
 
@@ -31,13 +33,17 @@ layout (std140, binding = EMULATION_UBO_BINDING) uniform vs_config {
 
 )";
 
-    const ShaderIR program_ir(setup.program.code, PROGRAM_OFFSET, setup.program.size_a);
+    CompilerSettings settings;
+    settings.depth = CompileDepth::NoFlowStack;
+
+    const ShaderIR program_ir(setup.program.code, PROGRAM_OFFSET, setup.program.size_a, settings);
     const auto stage = setup.IsDualProgram() ? ProgramType::VertexA : ProgramType::VertexB;
     ProgramResult program = Decompile(device, program_ir, stage, "vertex");
     out += program.first;
 
     if (setup.IsDualProgram()) {
-        const ShaderIR program_ir_b(setup.program.code_b, PROGRAM_OFFSET, setup.program.size_b);
+        const ShaderIR program_ir_b(setup.program.code_b, PROGRAM_OFFSET, setup.program.size_b,
+                                    settings);
         ProgramResult program_b = Decompile(device, program_ir_b, ProgramType::VertexB, "vertex_b");
         out += program_b.first;
     }
@@ -80,7 +86,10 @@ layout (std140, binding = EMULATION_UBO_BINDING) uniform gs_config {
 
 )";
 
-    const ShaderIR program_ir(setup.program.code, PROGRAM_OFFSET, setup.program.size_a);
+    CompilerSettings settings;
+    settings.depth = CompileDepth::NoFlowStack;
+
+    const ShaderIR program_ir(setup.program.code, PROGRAM_OFFSET, setup.program.size_a, settings);
     ProgramResult program = Decompile(device, program_ir, ProgramType::Geometry, "geometry");
     out += program.first;
 
@@ -114,7 +123,10 @@ layout (std140, binding = EMULATION_UBO_BINDING) uniform fs_config {
 };
 
 )";
-    const ShaderIR program_ir(setup.program.code, PROGRAM_OFFSET, setup.program.size_a);
+    CompilerSettings settings;
+    settings.depth = CompileDepth::NoFlowStack;
+
+    const ShaderIR program_ir(setup.program.code, PROGRAM_OFFSET, setup.program.size_a, settings);
     ProgramResult program = Decompile(device, program_ir, ProgramType::Fragment, "fragment");
     out += program.first;
 
@@ -133,7 +145,10 @@ ProgramResult GenerateComputeShader(const Device& device, const ShaderSetup& set
     std::string out = "// Shader Unique Id: CS" + id + "\n\n";
     out += GetCommonDeclarations();
 
-    const ShaderIR program_ir(setup.program.code, COMPUTE_OFFSET, setup.program.size_a);
+    CompilerSettings settings;
+    settings.depth = CompileDepth::NoFlowStack;
+
+    const ShaderIR program_ir(setup.program.code, COMPUTE_OFFSET, setup.program.size_a, settings);
     ProgramResult program = Decompile(device, program_ir, ProgramType::Compute, "compute");
     out += program.first;
 
diff --git a/src/video_core/shader/ast.cpp b/src/video_core/shader/ast.cpp
index 68a96cc79..14c50e1c6 100644
--- a/src/video_core/shader/ast.cpp
+++ b/src/video_core/shader/ast.cpp
@@ -363,7 +363,7 @@ std::string ASTManager::Print() {
     return printer.GetResult();
 }
 
-ASTManager::ASTManager() = default;
+ASTManager::ASTManager(bool full_decompile) : full_decompile{full_decompile} {};
 
 ASTManager::~ASTManager() {
     Clear();
@@ -383,6 +383,7 @@ ASTManager::ASTManager(ASTManager&& other)
 }
 
 ASTManager& ASTManager::operator=(ASTManager&& other) {
+    full_decompile = other.full_decompile;
     labels_map = std::move(other.labels_map);
     labels_count = other.labels_count;
     gotos = std::move(other.gotos);
@@ -434,6 +435,13 @@ void ASTManager::Decompile() {
         ASTNode goto_node = *it;
         u32 label_index = goto_node->GetGotoLabel();
         ASTNode label = labels[label_index];
+        if (!full_decompile) {
+            // We only decompile backward jumps
+            if (!IsBackwardsJump(goto_node, label)) {
+                it++;
+                continue;
+            }
+        }
         if (IndirectlyRelated(goto_node, label)) {
             while (!DirectlyRelated(goto_node, label)) {
                 MoveOutward(goto_node);
@@ -469,11 +477,91 @@ void ASTManager::Decompile() {
         }
         it++;
     }
-    for (ASTNode label : labels) {
-        auto& manager = label->GetManager();
-        manager.Remove(label);
+    if (full_decompile) {
+        for (ASTNode label : labels) {
+            auto& manager = label->GetManager();
+            manager.Remove(label);
+        }
+        labels.clear();
+    } else {
+        auto it = labels.begin();
+        while (it != labels.end()) {
+            bool can_remove = true;
+            ASTNode label = *it;
+            for (ASTNode goto_node : gotos) {
+                u32 label_index = goto_node->GetGotoLabel();
+                ASTNode glabel = labels[label_index];
+                if (glabel == label) {
+                    can_remove = false;
+                    break;
+                }
+            }
+            if (can_remove) {
+                auto& manager = label->GetManager();
+                manager.Remove(label);
+                labels.erase(it);
+            }
+        }
     }
-    labels.clear();
+}
+
+bool ASTManager::IsBackwardsJump(ASTNode goto_node, ASTNode label_node) const {
+    u32 goto_level = goto_node->GetLevel();
+    u32 label_level = label_node->GetLevel();
+    while (goto_level > label_level) {
+        goto_level--;
+        goto_node = goto_node->GetParent();
+    }
+    while (label_level > goto_level) {
+        label_level--;
+        label_node = label_node->GetParent();
+    }
+    while (goto_node->GetParent() != label_node->GetParent()) {
+        goto_node = goto_node->GetParent();
+        label_node = label_node->GetParent();
+    }
+    ASTNode current = goto_node->GetPrevious();
+    while (current) {
+        if (current == label_node) {
+            return true;
+        }
+        current = current->GetPrevious();
+    }
+    return false;
+}
+
+ASTNode CommonParent(ASTNode first, ASTNode second) {
+    if (first->GetParent() == second->GetParent()) {
+        return first->GetParent();
+    }
+    u32 first_level = first->GetLevel();
+    u32 second_level = second->GetLevel();
+    u32 min_level;
+    u32 max_level;
+    ASTNode max;
+    ASTNode min;
+    if (first_level > second_level) {
+        min_level = second_level;
+        min = second;
+        max_level = first_level;
+        max = first;
+    } else {
+        min_level = first_level;
+        min = first;
+        max_level = second_level;
+        max = second;
+    }
+
+    while (max_level > min_level) {
+        max_level--;
+        max = max->GetParent();
+    }
+
+    while (min->GetParent() != max->GetParent()) {
+        min = min->GetParent();
+        max = max->GetParent();
+    }
+    return min->GetParent();
 }
 
 bool ASTManager::IndirectlyRelated(ASTNode first, ASTNode second) {
diff --git a/src/video_core/shader/ast.h b/src/video_core/shader/ast.h
index 06ab20cc5..849d0612c 100644
--- a/src/video_core/shader/ast.h
+++ b/src/video_core/shader/ast.h
@@ -274,7 +274,7 @@ private:
 
 class ASTManager final {
 public:
-    ASTManager();
+    ASTManager(bool full_decompile);
     ~ASTManager();
 
     ASTManager(const ASTManager& o) = delete;
@@ -304,7 +304,18 @@ public:
     void SanityCheck();
 
     bool IsFullyDecompiled() const {
-        return gotos.size() == 0;
+        if (full_decompile) {
+            return gotos.size() == 0;
+        } else {
+            for (ASTNode goto_node : gotos) {
+                u32 label_index = goto_node->GetGotoLabel();
+                ASTNode glabel = labels[label_index];
+                if (IsBackwardsJump(goto_node, glabel)) {
+                    return false;
+                }
+            }
+            return true;
+        }
     }
 
     ASTNode GetProgram() const {
@@ -318,6 +329,10 @@ public:
     }
 
 private:
+    bool IsBackwardsJump(ASTNode goto_node, ASTNode label_node) const;
+
+    ASTNode CommonParent(ASTNode first, ASTNode second);
+
     bool IndirectlyRelated(ASTNode first, ASTNode second);
 
     bool DirectlyRelated(ASTNode first, ASTNode second);
@@ -334,6 +349,7 @@ private:
         return new_var;
     }
 
+    bool full_decompile{};
     std::unordered_map<u32, u32> labels_map{};
     u32 labels_count{};
     std::vector<ASTNode> labels{};
diff --git a/src/video_core/shader/compiler_settings.cpp b/src/video_core/shader/compiler_settings.cpp
new file mode 100644
index 000000000..cddcbd4f0
--- /dev/null
+++ b/src/video_core/shader/compiler_settings.cpp
@@ -0,0 +1,26 @@
+// Copyright 2019 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "video_core/shader/compiler_settings.h"
+
+namespace VideoCommon::Shader {
+
+std::string CompileDepthAsString(const CompileDepth cd) {
+    switch (cd) {
+    case CompileDepth::BruteForce:
+        return "Brute Force Compile";
+    case CompileDepth::FlowStack:
+        return "Simple Flow Stack Mode";
+    case CompileDepth::NoFlowStack:
+        return "Remove Flow Stack";
+    case CompileDepth::DecompileBackwards:
+        return "Decompile Backward Jumps";
+    case CompileDepth::FullDecompile:
+        return "Full Decompilation";
+    default:
+        return "Unknown Compiler Process";
+    }
+}
+
+} // namespace VideoCommon::Shader
diff --git a/src/video_core/shader/compiler_settings.h b/src/video_core/shader/compiler_settings.h
new file mode 100644
index 000000000..e1fb5bc3a
--- /dev/null
+++ b/src/video_core/shader/compiler_settings.h
@@ -0,0 +1,25 @@
+// Copyright 2019 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "video_core/engines/shader_bytecode.h"
+
+namespace VideoCommon::Shader {
+
+enum class CompileDepth : u32 {
+    BruteForce = 0,
+    FlowStack = 1,
+    NoFlowStack = 2,
+    DecompileBackwards = 3,
+    FullDecompile = 4,
+};
+
+std::string CompileDepthAsString(CompileDepth cd);
+
+struct CompilerSettings {
+    CompileDepth depth;
+};
+
+} // namespace VideoCommon::Shader
diff --git a/src/video_core/shader/control_flow.cpp b/src/video_core/shader/control_flow.cpp
index a29922815..c4351969b 100644
--- a/src/video_core/shader/control_flow.cpp
+++ b/src/video_core/shader/control_flow.cpp
@@ -57,8 +57,8 @@ struct BlockInfo {
 
 struct CFGRebuildState {
     explicit CFGRebuildState(const ProgramCode& program_code, const std::size_t program_size,
-                             const u32 start, ASTManager& manager)
-        : program_code{program_code}, program_size{program_size}, start{start}, manager{manager} {}
+                             const u32 start)
+        : program_code{program_code}, program_size{program_size}, start{start} {}
 
     u32 start{};
     std::vector<BlockInfo> block_info{};
@@ -71,7 +71,7 @@ struct CFGRebuildState {
     std::unordered_map<u32, BlockStack> stacks{};
     const ProgramCode& program_code;
     const std::size_t program_size;
-    ASTManager& manager;
+    ASTManager* manager;
 };
 
 enum class BlockCollision : u32 { None, Found, Inside };
@@ -456,67 +456,91 @@ void InsertBranch(ASTManager& mm, const BlockBranchInfo& branch) {
 }
 
 void DecompileShader(CFGRebuildState& state) {
-    state.manager.Init();
+    state.manager->Init();
     for (auto label : state.labels) {
-        state.manager.DeclareLabel(label);
+        state.manager->DeclareLabel(label);
     }
     for (auto& block : state.block_info) {
         if (state.labels.count(block.start) != 0) {
-            state.manager.InsertLabel(block.start);
+            state.manager->InsertLabel(block.start);
         }
         u32 end = block.branch.ignore ? block.end + 1 : block.end;
-        state.manager.InsertBlock(block.start, end);
+        state.manager->InsertBlock(block.start, end);
         if (!block.branch.ignore) {
-            InsertBranch(state.manager, block.branch);
+            InsertBranch(*state.manager, block.branch);
         }
     }
-    // state.manager.ShowCurrentState("Before Decompiling");
-    state.manager.Decompile();
-    // state.manager.ShowCurrentState("After Decompiling");
+    state.manager->Decompile();
 }
 
 std::unique_ptr<ShaderCharacteristics> ScanFlow(const ProgramCode& program_code, u32 program_size,
-                                                u32 start_address, ASTManager& manager) {
-    CFGRebuildState state{program_code, program_size, start_address, manager};
+                                                u32 start_address,
+                                                const CompilerSettings& settings) {
+    auto result_out = std::make_unique<ShaderCharacteristics>();
+    if (settings.depth == CompileDepth::BruteForce) {
+        result_out->settings.depth = CompileDepth::BruteForce;
+        return std::move(result_out);
+    }
+
+    CFGRebuildState state{program_code, program_size, start_address};
     // Inspect Code and generate blocks
     state.labels.clear();
     state.labels.emplace(start_address);
     state.inspect_queries.push_back(state.start);
     while (!state.inspect_queries.empty()) {
         if (!TryInspectAddress(state)) {
-            return {};
+            result_out->settings.depth = CompileDepth::BruteForce;
+            return std::move(result_out);
         }
     }
 
-    // Decompile Stacks
-    state.queries.push_back(Query{state.start, {}, {}});
-    bool decompiled = true;
-    while (!state.queries.empty()) {
-        if (!TryQuery(state)) {
-            decompiled = false;
-            break;
+    bool use_flow_stack = true;
+
+    bool decompiled = false;
+
+    if (settings.depth != CompileDepth::FlowStack) {
+        // Decompile Stacks
+        state.queries.push_back(Query{state.start, {}, {}});
+        decompiled = true;
+        while (!state.queries.empty()) {
+            if (!TryQuery(state)) {
+                decompiled = false;
+                break;
+            }
         }
     }
 
+    use_flow_stack = !decompiled;
+
     // Sort and organize results
     std::sort(state.block_info.begin(), state.block_info.end(),
               [](const BlockInfo& a, const BlockInfo& b) -> bool { return a.start < b.start; });
-    if (decompiled) {
+    if (decompiled && settings.depth != CompileDepth::NoFlowStack) {
+        ASTManager manager{settings.depth != CompileDepth::DecompileBackwards};
+        state.manager = &manager;
         DecompileShader(state);
-        decompiled = state.manager.IsFullyDecompiled();
+        decompiled = state.manager->IsFullyDecompiled();
         if (!decompiled) {
-            LOG_CRITICAL(HW_GPU, "Failed to remove all the gotos!:");
-            state.manager.ShowCurrentState("Of Shader");
-            state.manager.Clear();
+            if (settings.depth == CompileDepth::FullDecompile) {
+                LOG_CRITICAL(HW_GPU, "Failed to remove all the gotos!:");
+            } else {
+                LOG_CRITICAL(HW_GPU, "Failed to remove all backward gotos!:");
+            }
+            state.manager->ShowCurrentState("Of Shader");
+            state.manager->Clear();
+        } else {
+            auto result_out = std::make_unique<ShaderCharacteristics>();
+            result_out->start = start_address;
+            result_out->settings.depth = settings.depth;
+            result_out->manager = std::move(manager);
+            result_out->end = state.block_info.back().end + 1;
+            return std::move(result_out);
         }
     }
-    auto result_out = std::make_unique<ShaderCharacteristics>();
-    result_out->decompiled = decompiled;
     result_out->start = start_address;
-    if (decompiled) {
-        result_out->end = state.block_info.back().end + 1;
-        return std::move(result_out);
-    }
+    result_out->settings.depth =
+        use_flow_stack ? CompileDepth::FlowStack : CompileDepth::NoFlowStack;
+    result_out->blocks.clear();
     for (auto& block : state.block_info) {
         ShaderBlock new_block{};
         new_block.start = block.start;
@@ -530,6 +554,10 @@ std::unique_ptr<ShaderCharacteristics> ScanFlow(const ProgramCode& program_code,
         result_out->end = std::max(result_out->end, block.end);
         result_out->blocks.push_back(new_block);
     }
+    if (!use_flow_stack) {
+        result_out->labels = std::move(state.labels);
+        return std::move(result_out);
+    }
     auto back = result_out->blocks.begin();
     auto next = std::next(back);
     while (next != result_out->blocks.end()) {
diff --git a/src/video_core/shader/control_flow.h b/src/video_core/shader/control_flow.h
index 347a35dcf..8d0d08422 100644
--- a/src/video_core/shader/control_flow.h
+++ b/src/video_core/shader/control_flow.h
@@ -9,8 +9,9 @@
 #include <set>
 
 #include "video_core/engines/shader_bytecode.h"
-#include "video_core/shader/shader_ir.h"
 #include "video_core/shader/ast.h"
+#include "video_core/shader/compiler_settings.h"
+#include "video_core/shader/shader_ir.h"
 
 namespace VideoCommon::Shader {
 
@@ -68,12 +69,15 @@ struct ShaderBlock {
 
 struct ShaderCharacteristics {
     std::list<ShaderBlock> blocks{};
-    bool decompiled{};
+    std::set<u32> labels{};
     u32 start{};
     u32 end{};
+    ASTManager manager{true};
+    CompilerSettings settings{};
 };
 
 std::unique_ptr<ShaderCharacteristics> ScanFlow(const ProgramCode& program_code, u32 program_size,
-                                                u32 start_address, ASTManager& manager);
+                                                u32 start_address,
+                                                const CompilerSettings& settings);
 
 } // namespace VideoCommon::Shader
diff --git a/src/video_core/shader/decode.cpp b/src/video_core/shader/decode.cpp
index e7e0903f6..6d4359295 100644
--- a/src/video_core/shader/decode.cpp
+++ b/src/video_core/shader/decode.cpp
@@ -102,35 +102,71 @@ void ShaderIR::Decode() {
     std::memcpy(&header, program_code.data(), sizeof(Tegra::Shader::Header));
 
     decompiled = false;
-    const auto info =
-        ScanFlow(program_code, program_size, main_offset, program_manager);
-    if (info) {
-        const auto& shader_info = *info;
-        coverage_begin = shader_info.start;
-        coverage_end = shader_info.end;
-        if (shader_info.decompiled) {
-            decompiled = true;
-            ASTDecoder decoder{*this};
-            ASTNode program = GetASTProgram();
-            decoder.Visit(program);
-            return;
-        }
-        LOG_WARNING(HW_GPU, "Flow Stack Removing Failed! Falling back to old method");
-        // we can't decompile it, fallback to standard method
+    auto info = ScanFlow(program_code, program_size, main_offset, settings);
+    auto& shader_info = *info;
+    coverage_begin = shader_info.start;
+    coverage_end = shader_info.end;
+    switch (shader_info.settings.depth) {
+    case CompileDepth::FlowStack: {
         for (const auto& block : shader_info.blocks) {
             basic_blocks.insert({block.start, DecodeRange(block.start, block.end + 1)});
         }
-        return;
+        break;
+    }
+    case CompileDepth::NoFlowStack: {
+        disable_flow_stack = true;
+        const auto insert_block = [this](NodeBlock& nodes, u32 label) {
+            if (label == static_cast<u32>(exit_branch)) {
+                return;
+            }
+            basic_blocks.insert({label, nodes});
+        };
+        const auto& blocks = shader_info.blocks;
+        NodeBlock current_block;
+        u32 current_label = static_cast<u32>(exit_branch);
+        for (auto& block : blocks) {
+            if (shader_info.labels.count(block.start) != 0) {
+                insert_block(current_block, current_label);
+                current_block.clear();
+                current_label = block.start;
+            }
+            if (!block.ignore_branch) {
+                DecodeRangeInner(current_block, block.start, block.end);
+                InsertControlFlow(current_block, block);
+            } else {
+                DecodeRangeInner(current_block, block.start, block.end + 1);
+            }
+        }
+        insert_block(current_block, current_label);
+        break;
+    }
+    case CompileDepth::DecompileBackwards:
+    case CompileDepth::FullDecompile: {
+        program_manager = std::move(shader_info.manager);
+        disable_flow_stack = true;
+        decompiled = true;
+        ASTDecoder decoder{*this};
+        ASTNode program = GetASTProgram();
+        decoder.Visit(program);
+        break;
+    }
+    default:
+        LOG_CRITICAL(HW_GPU, "Unknown decompilation mode!");
+        [[fallthrough]];
+    case CompileDepth::BruteForce: {
+        coverage_begin = main_offset;
+        const u32 shader_end = static_cast<u32>(program_size / sizeof(u64));
+        coverage_end = shader_end;
+        for (u32 label = main_offset; label < shader_end; label++) {
+            basic_blocks.insert({label, DecodeRange(label, label + 1)});
+        }
+        break;
+    }
     }
-    LOG_WARNING(HW_GPU, "Flow Analysis Failed! Falling back to brute force compiling");
-
-    // Now we need to deal with an undecompilable shader. We need to brute force
-    // a shader that captures every position.
-    coverage_begin = main_offset;
-    const u32 shader_end = static_cast<u32>(program_size / sizeof(u64));
-    coverage_end = shader_end;
-    for (u32 label = main_offset; label < shader_end; label++) {
-        basic_blocks.insert({label, DecodeRange(label, label + 1)});
+    if (settings.depth != shader_info.settings.depth) {
+        LOG_WARNING(
+            HW_GPU, "Decompiling to this setting \"{}\" failed, downgrading to this setting \"{}\"",
+            CompileDepthAsString(settings.depth), CompileDepthAsString(shader_info.settings.depth));
     }
 }
 
diff --git a/src/video_core/shader/decode/other.cpp b/src/video_core/shader/decode/other.cpp
index 6f678003c..d46e0f823 100644
--- a/src/video_core/shader/decode/other.cpp
+++ b/src/video_core/shader/decode/other.cpp
@@ -157,7 +157,7 @@ u32 ShaderIR::DecodeOther(NodeBlock& bb, u32 pc) {
         UNIMPLEMENTED_IF_MSG(instr.bra.constant_buffer != 0,
                              "Constant buffer flow is not supported");
 
-        if (decompiled) {
+        if (disable_flow_stack) {
             break;
         }
 
@@ -171,7 +171,7 @@ u32 ShaderIR::DecodeOther(NodeBlock& bb, u32 pc) {
         UNIMPLEMENTED_IF_MSG(instr.bra.constant_buffer != 0,
                              "Constant buffer PBK is not supported");
 
-        if (decompiled) {
+        if (disable_flow_stack) {
             break;
         }
 
@@ -186,7 +186,7 @@ u32 ShaderIR::DecodeOther(NodeBlock& bb, u32 pc) {
         UNIMPLEMENTED_IF_MSG(cc != Tegra::Shader::ConditionCode::T, "SYNC condition code used: {}",
                              static_cast<u32>(cc));
 
-        if (decompiled) {
+        if (disable_flow_stack) {
             break;
         }
 
@@ -198,7 +198,7 @@ u32 ShaderIR::DecodeOther(NodeBlock& bb, u32 pc) {
         const Tegra::Shader::ConditionCode cc = instr.flow_condition_code;
         UNIMPLEMENTED_IF_MSG(cc != Tegra::Shader::ConditionCode::T, "BRK condition code used: {}",
                              static_cast<u32>(cc));
-        if (decompiled) {
+        if (disable_flow_stack) {
             break;
         }
 
diff --git a/src/video_core/shader/shader_ir.cpp b/src/video_core/shader/shader_ir.cpp
index 004b1e16f..04e364634 100644
--- a/src/video_core/shader/shader_ir.cpp
+++ b/src/video_core/shader/shader_ir.cpp
@@ -22,8 +22,10 @@ using Tegra::Shader::PredCondition;
 using Tegra::Shader::PredOperation;
 using Tegra::Shader::Register;
 
-ShaderIR::ShaderIR(const ProgramCode& program_code, u32 main_offset, const std::size_t size)
-    : program_code{program_code}, main_offset{main_offset}, program_size{size}, program_manager{} {
+ShaderIR::ShaderIR(const ProgramCode& program_code, u32 main_offset, const std::size_t size,
+                   CompilerSettings settings)
+    : program_code{program_code}, main_offset{main_offset}, program_size{size}, basic_blocks{},
+      program_manager{true}, settings{settings} {
     Decode();
 }
 
diff --git a/src/video_core/shader/shader_ir.h b/src/video_core/shader/shader_ir.h
index 48c7b722e..7a91c9bb6 100644
--- a/src/video_core/shader/shader_ir.h
+++ b/src/video_core/shader/shader_ir.h
@@ -16,6 +16,7 @@
 #include "video_core/engines/shader_bytecode.h"
 #include "video_core/engines/shader_header.h"
 #include "video_core/shader/ast.h"
+#include "video_core/shader/compiler_settings.h"
 #include "video_core/shader/node.h"
 
 namespace VideoCommon::Shader {
@@ -65,7 +66,8 @@ struct GlobalMemoryUsage {
 
 class ShaderIR final {
 public:
-    explicit ShaderIR(const ProgramCode& program_code, u32 main_offset, std::size_t size);
+    explicit ShaderIR(const ProgramCode& program_code, u32 main_offset, std::size_t size,
+                      CompilerSettings settings);
     ~ShaderIR();
 
     const std::map<u32, NodeBlock>& GetBasicBlocks() const {
@@ -141,6 +143,10 @@ public:
         return header;
     }
 
+    bool IsFlowStackDisabled() const {
+        return disable_flow_stack;
+    }
+
     bool IsDecompiled() const {
         return decompiled;
     }
@@ -368,6 +374,7 @@ private:
     const u32 main_offset;
     const std::size_t program_size;
     bool decompiled{};
+    bool disable_flow_stack{};
 
     u32 coverage_begin{};
     u32 coverage_end{};
@@ -375,6 +382,7 @@ private:
     std::map<u32, NodeBlock> basic_blocks;
     NodeBlock global_code;
     ASTManager program_manager;
+    CompilerSettings settings{};
 
     std::set<u32> used_registers;
     std::set<Tegra::Shader::Pred> used_predicates;
-- 
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