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gl_shader_decompiler: Implement AST decompiling

This commit is contained in:
Fernando Sahmkow 2019-06-29 01:44:07 -04:00 committed by FernandoS27
parent 6fdd501113
commit 38fc995f6c
11 changed files with 358 additions and 63 deletions
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271
src/video_core/renderer_opengl/gl_shader_decompiler.cpp
View File

@ -20,6 +20,7 @@
#include "video_core/renderer_opengl/gl_rasterizer.h"
#include "video_core/renderer_opengl/gl_shader_decompiler.h"
#include "video_core/shader/node.h"
#include "video_core/shader/ast.h"
#include "video_core/shader/shader_ir.h"
namespace OpenGL::GLShader {
@ -334,43 +335,26 @@ constexpr bool IsVertexShader(ProgramType stage) {
return stage == ProgramType::VertexA || stage == ProgramType::VertexB;
}
class ASTDecompiler;
class ExprDecompiler;
class GLSLDecompiler final {
public:
explicit GLSLDecompiler(const Device& device, const ShaderIR& ir, ProgramType stage,
std::string suffix)
: device{device}, ir{ir}, stage{stage}, suffix{suffix}, header{ir.GetHeader()} {}
void Decompile() {
DeclareVertex();
DeclareGeometry();
DeclareRegisters();
DeclarePredicates();
DeclareLocalMemory();
DeclareSharedMemory();
DeclareInternalFlags();
DeclareInputAttributes();
DeclareOutputAttributes();
DeclareConstantBuffers();
DeclareGlobalMemory();
DeclareSamplers();
DeclarePhysicalAttributeReader();
DeclareImages();
code.AddLine("void execute_{}() {{", suffix);
++code.scope;
void DecompileBranchMode() {
// VM's program counter
const auto first_address = ir.GetBasicBlocks().begin()->first;
code.AddLine("uint jmp_to = {}U;", first_address);
// 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.
if (!ir.IsFlowStackDisabled()) {
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));
}
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));
}
code.AddLine("while (true) {{");
@ -392,10 +376,37 @@ public:
code.AddLine("default: return;");
code.AddLine("}}");
for (std::size_t i = 0; i < 2; ++i) {
--code.scope;
code.AddLine("}}");
--code.scope;
code.AddLine("}}");
}
void DecompileAST();
void Decompile() {
DeclareVertex();
DeclareGeometry();
DeclareRegisters();
DeclarePredicates();
DeclareLocalMemory();
DeclareInternalFlags();
DeclareInputAttributes();
DeclareOutputAttributes();
DeclareConstantBuffers();
DeclareGlobalMemory();
DeclareSamplers();
DeclarePhysicalAttributeReader();
code.AddLine("void execute_{}() {{", suffix);
++code.scope;
if (ir.IsDecompiled()) {
DecompileAST();
} else {
DecompileBranchMode();
}
--code.scope;
code.AddLine("}}");
}
std::string GetResult() {
@ -424,6 +435,9 @@ public:
}
private:
friend class ASTDecompiler;
friend class ExprDecompiler;
void DeclareVertex() {
if (!IsVertexShader(stage))
return;
@ -1821,7 +1835,7 @@ private:
return {};
}
Expression Exit(Operation operation) {
Expression WriteExit() {
if (stage != ProgramType::Fragment) {
code.AddLine("return;");
return {};
@ -1861,6 +1875,10 @@ private:
return {};
}
Expression Exit(Operation operation) {
return WriteExit();
}
Expression Discard(Operation operation) {
// Enclose "discard" in a conditional, so that GLSL compilation does not complain
// about unexecuted instructions that may follow this.
@ -2253,6 +2271,201 @@ private:
ShaderWriter code;
};
const std::string flow_var = "flow_var_";
class ExprDecompiler {
public:
ExprDecompiler(GLSLDecompiler& decomp) : decomp{decomp} {}
void operator()(VideoCommon::Shader::ExprAnd& expr) {
inner += "( ";
std::visit(*this, *expr.operand1);
inner += " && ";
std::visit(*this, *expr.operand2);
inner += ')';
}
void operator()(VideoCommon::Shader::ExprOr& expr) {
inner += "( ";
std::visit(*this, *expr.operand1);
inner += " || ";
std::visit(*this, *expr.operand2);
inner += ')';
}
void operator()(VideoCommon::Shader::ExprNot& expr) {
inner += '!';
std::visit(*this, *expr.operand1);
}
void operator()(VideoCommon::Shader::ExprPredicate& expr) {
auto pred = static_cast<Tegra::Shader::Pred>(expr.predicate);
inner += decomp.GetPredicate(pred);
}
void operator()(VideoCommon::Shader::ExprCondCode& expr) {
Node cc = decomp.ir.GetConditionCode(expr.cc);
std::string target;
if (const auto pred = std::get_if<PredicateNode>(&*cc)) {
const auto index = pred->GetIndex();
switch (index) {
case Tegra::Shader::Pred::NeverExecute:
target = "false";
case Tegra::Shader::Pred::UnusedIndex:
target = "true";
default:
target = decomp.GetPredicate(index);
}
} else if (const auto flag = std::get_if<InternalFlagNode>(&*cc)) {
target = decomp.GetInternalFlag(flag->GetFlag());
}
inner += target;
}
void operator()(VideoCommon::Shader::ExprVar& expr) {
inner += flow_var + std::to_string(expr.var_index);
}
void operator()(VideoCommon::Shader::ExprBoolean& expr) {
inner += expr.value ? "true" : "false";
}
std::string& GetResult() {
return inner;
}
private:
std::string inner{};
GLSLDecompiler& decomp;
};
class ASTDecompiler {
public:
ASTDecompiler(GLSLDecompiler& decomp) : decomp{decomp} {}
void operator()(VideoCommon::Shader::ASTProgram& ast) {
ASTNode current = ast.nodes.GetFirst();
while (current) {
Visit(current);
current = current->GetNext();
}
}
void operator()(VideoCommon::Shader::ASTIfThen& ast) {
ExprDecompiler expr_parser{decomp};
std::visit(expr_parser, *ast.condition);
decomp.code.AddLine("if ({}) {{", expr_parser.GetResult());
decomp.code.scope++;
ASTNode current = ast.nodes.GetFirst();
while (current) {
Visit(current);
current = current->GetNext();
}
decomp.code.scope--;
decomp.code.AddLine("}}");
}
void operator()(VideoCommon::Shader::ASTIfElse& ast) {
decomp.code.AddLine("else {{");
decomp.code.scope++;
ASTNode current = ast.nodes.GetFirst();
while (current) {
Visit(current);
current = current->GetNext();
}
decomp.code.scope--;
decomp.code.AddLine("}}");
}
void operator()(VideoCommon::Shader::ASTBlockEncoded& ast) {
UNREACHABLE();
}
void operator()(VideoCommon::Shader::ASTBlockDecoded& ast) {
decomp.VisitBlock(ast.nodes);
}
void operator()(VideoCommon::Shader::ASTVarSet& ast) {
ExprDecompiler expr_parser{decomp};
std::visit(expr_parser, *ast.condition);
decomp.code.AddLine("{}{} = {};", flow_var, ast.index, expr_parser.GetResult());
}
void operator()(VideoCommon::Shader::ASTLabel& ast) {
decomp.code.AddLine("// Label_{}:", ast.index);
}
void operator()(VideoCommon::Shader::ASTGoto& ast) {
UNREACHABLE();
}
void operator()(VideoCommon::Shader::ASTDoWhile& ast) {
ExprDecompiler expr_parser{decomp};
std::visit(expr_parser, *ast.condition);
decomp.code.AddLine("do {{");
decomp.code.scope++;
ASTNode current = ast.nodes.GetFirst();
while (current) {
Visit(current);
current = current->GetNext();
}
decomp.code.scope--;
decomp.code.AddLine("}} while({});", expr_parser.GetResult());
}
void operator()(VideoCommon::Shader::ASTReturn& ast) {
bool is_true = VideoCommon::Shader::ExprIsTrue(ast.condition);
if (!is_true) {
ExprDecompiler expr_parser{decomp};
std::visit(expr_parser, *ast.condition);
decomp.code.AddLine("if ({}) {{", expr_parser.GetResult());
decomp.code.scope++;
}
if (ast.kills) {
decomp.code.AddLine("discard;");
} else {
decomp.WriteExit();
}
if (!is_true) {
decomp.code.scope--;
decomp.code.AddLine("}}");
}
}
void operator()(VideoCommon::Shader::ASTBreak& ast) {
bool is_true = VideoCommon::Shader::ExprIsTrue(ast.condition);
if (!is_true) {
ExprDecompiler expr_parser{decomp};
std::visit(expr_parser, *ast.condition);
decomp.code.AddLine("if ({}) {{", expr_parser.GetResult());
decomp.code.scope++;
}
decomp.code.AddLine("break;");
if (!is_true) {
decomp.code.scope--;
decomp.code.AddLine("}}");
}
}
void Visit(VideoCommon::Shader::ASTNode& node) {
std::visit(*this, *node->GetInnerData());
}
private:
GLSLDecompiler& decomp;
};
void GLSLDecompiler::DecompileAST() {
u32 num_flow_variables = ir.GetASTNumVariables();
for (u32 i = 0; i < num_flow_variables; i++) {
code.AddLine("bool {}{} = false;", flow_var, i);
}
ASTDecompiler decompiler{*this};
VideoCommon::Shader::ASTNode program = ir.GetASTProgram();
decompiler.Visit(program);
}
} // Anonymous namespace
std::string GetCommonDeclarations() {

10
src/video_core/shader/ast.cpp
View File

@ -372,13 +372,13 @@ ASTManager::~ASTManager() {
void ASTManager::Init() {
main_node = ASTBase::Make<ASTProgram>(ASTNode{});
program = std::get_if<ASTProgram>(main_node->GetInnerData());
true_condition = MakeExpr<ExprBoolean>(true);
false_condition = MakeExpr<ExprBoolean>(false);
}
ASTManager::ASTManager(ASTManager&& other)
: labels_map(std::move(other.labels_map)), labels_count{other.labels_count},
gotos(std::move(other.gotos)), labels(std::move(other.labels)), variables{other.variables},
program{other.program}, main_node{other.main_node}, true_condition{other.true_condition} {
program{other.program}, main_node{other.main_node}, false_condition{other.false_condition} {
other.main_node.reset();
}
@ -390,7 +390,7 @@ ASTManager& ASTManager::operator=(ASTManager&& other) {
variables = other.variables;
program = other.program;
main_node = other.main_node;
true_condition = other.true_condition;
false_condition = other.false_condition;
other.main_node.reset();
return *this;
@ -594,7 +594,7 @@ void ASTManager::MoveOutward(ASTNode goto_node) {
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);
ASTNode var_node_init = ASTBase::Make<ASTVarSet>(parent, var_index, false_condition);
zipper2.InsertBefore(var_node_init, parent);
zipper.InsertAfter(var_node, prev);
goto_node->SetGotoCondition(var_condition);
@ -605,7 +605,7 @@ void ASTManager::MoveOutward(ASTNode goto_node) {
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);
ASTNode var_node_init = ASTBase::Make<ASTVarSet>(parent, var_index, false_condition);
if (is_if) {
zipper2.InsertBefore(var_node_init, parent);
} else {

18
src/video_core/shader/ast.h
View File

@ -141,8 +141,6 @@ 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} {}
@ -233,11 +231,7 @@ public:
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);
void TransformBlockEncoded(NodeBlock& nodes) {
data = ASTBlockDecoded(nodes);
}
@ -309,16 +303,20 @@ public:
void SanityCheck();
bool IsFullyDecompiled() {
bool IsFullyDecompiled() const {
return gotos.size() == 0;
}
ASTNode GetProgram() {
ASTNode GetProgram() const {
return main_node;
}
void Clear();
u32 GetVariables() const {
return variables;
}
private:
bool IndirectlyRelated(ASTNode first, ASTNode second);
@ -343,7 +341,7 @@ private:
u32 variables{};
ASTProgram* program{};
ASTNode main_node{};
Expr true_condition{};
Expr false_condition{};
};
} // namespace VideoCommon::Shader

2
src/video_core/shader/control_flow.cpp
View File

@ -425,7 +425,7 @@ void InsertBranch(ASTManager& mm, const BlockBranchInfo& branch) {
}
if (cond.predicate != Pred::UnusedIndex) {
u32 pred = static_cast<u32>(cond.predicate);
bool negate;
bool negate = false;
if (pred > 7) {
negate = true;
pred -= 8;

2
src/video_core/shader/control_flow.h
View File

@ -74,6 +74,6 @@ struct ShaderCharacteristics {
};
std::unique_ptr<ShaderCharacteristics> ScanFlow(const ProgramCode& program_code, u32 program_size,
u32 start_address, ASTManager& manager);
u32 start_address, ASTManager& manager);
} // namespace VideoCommon::Shader

70
src/video_core/shader/decode.cpp
View File

@ -35,10 +35,73 @@ constexpr bool IsSchedInstruction(u32 offset, u32 main_offset) {
} // namespace
class ASTDecoder {
public:
ASTDecoder(ShaderIR& ir) : ir(ir) {}
void operator()(ASTProgram& ast) {
ASTNode current = ast.nodes.GetFirst();
while (current) {
Visit(current);
current = current->GetNext();
}
}
void operator()(ASTIfThen& ast) {
ASTNode current = ast.nodes.GetFirst();
while (current) {
Visit(current);
current = current->GetNext();
}
}
void operator()(ASTIfElse& ast) {
ASTNode current = ast.nodes.GetFirst();
while (current) {
Visit(current);
current = current->GetNext();
}
}
void operator()(ASTBlockEncoded& ast) {}
void operator()(ASTBlockDecoded& ast) {}
void operator()(ASTVarSet& ast) {}
void operator()(ASTLabel& ast) {}
void operator()(ASTGoto& ast) {}
void operator()(ASTDoWhile& ast) {
ASTNode current = ast.nodes.GetFirst();
while (current) {
Visit(current);
current = current->GetNext();
}
}
void operator()(ASTReturn& ast) {}
void operator()(ASTBreak& ast) {}
void Visit(ASTNode& node) {
std::visit(*this, *node->GetInnerData());
if (node->IsBlockEncoded()) {
auto block = std::get_if<ASTBlockEncoded>(node->GetInnerData());
NodeBlock bb = ir.DecodeRange(block->start, block->end);
node->TransformBlockEncoded(bb);
}
}
private:
ShaderIR& ir;
};
void ShaderIR::Decode() {
std::memcpy(&header, program_code.data(), sizeof(Tegra::Shader::Header));
disable_flow_stack = false;
decompiled = false;
const auto info =
ScanFlow(program_code, program_size, main_offset, program_manager);
if (info) {
@ -46,7 +109,10 @@ void ShaderIR::Decode() {
coverage_begin = shader_info.start;
coverage_end = shader_info.end;
if (shader_info.decompiled) {
disable_flow_stack = true;
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");

8
src/video_core/shader/decode/other.cpp
View File

@ -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 (disable_flow_stack) {
if (decompiled) {
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 (disable_flow_stack) {
if (decompiled) {
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 (disable_flow_stack) {
if (decompiled) {
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 (disable_flow_stack) {
if (decompiled) {
break;
}

7
src/video_core/shader/expr.cpp
View File

@ -72,4 +72,11 @@ bool ExprAreOpposite(Expr first, Expr second) {
return false;
}
bool ExprIsTrue(Expr first) {
if (ExprIsBoolean(first)) {
return ExprBooleanGet(first);
}
return false;
}
} // namespace VideoCommon::Shader

2
src/video_core/shader/expr.h
View File

@ -115,4 +115,6 @@ Expr MakeExprAnd(Expr first, Expr second);
Expr MakeExprOr(Expr first, Expr second);
bool ExprIsTrue(Expr first);
} // namespace VideoCommon::Shader

6
src/video_core/shader/shader_ir.cpp
View File

@ -137,7 +137,7 @@ Node ShaderIR::GetOutputAttribute(Attribute::Index index, u64 element, Node buff
return MakeNode<AbufNode>(index, static_cast<u32>(element), std::move(buffer));
}
Node ShaderIR::GetInternalFlag(InternalFlag flag, bool negated) {
Node ShaderIR::GetInternalFlag(InternalFlag flag, bool negated) const {
const Node node = MakeNode<InternalFlagNode>(flag);
if (negated) {
return Operation(OperationCode::LogicalNegate, node);
@ -367,13 +367,13 @@ OperationCode ShaderIR::GetPredicateCombiner(PredOperation operation) {
return op->second;
}
Node ShaderIR::GetConditionCode(Tegra::Shader::ConditionCode cc) {
Node ShaderIR::GetConditionCode(Tegra::Shader::ConditionCode cc) const {
switch (cc) {
case Tegra::Shader::ConditionCode::NEU:
return GetInternalFlag(InternalFlag::Zero, true);
default:
UNIMPLEMENTED_MSG("Unimplemented condition code: {}", static_cast<u32>(cc));
return GetPredicate(static_cast<u64>(Pred::NeverExecute));
return MakeNode<PredicateNode>(Pred::NeverExecute, false);
}
}

25
src/video_core/shader/shader_ir.h
View File

@ -15,8 +15,8 @@
#include "video_core/engines/maxwell_3d.h"
#include "video_core/engines/shader_bytecode.h"
#include "video_core/engines/shader_header.h"
#include "video_core/shader/node.h"
#include "video_core/shader/ast.h"
#include "video_core/shader/node.h"
namespace VideoCommon::Shader {
@ -141,15 +141,27 @@ public:
return header;
}
bool IsFlowStackDisabled() const {
return disable_flow_stack;
bool IsDecompiled() const {
return decompiled;
}
ASTNode GetASTProgram() const {
return program_manager.GetProgram();
}
u32 GetASTNumVariables() const {
return program_manager.GetVariables();
}
u32 ConvertAddressToNvidiaSpace(const u32 address) const {
return (address - main_offset) * sizeof(Tegra::Shader::Instruction);
}
/// Returns a condition code evaluated from internal flags
Node GetConditionCode(Tegra::Shader::ConditionCode cc) const;
private:
friend class ASTDecoder;
void Decode();
NodeBlock DecodeRange(u32 begin, u32 end);
@ -214,7 +226,7 @@ private:
/// Generates a node representing an output attribute. Keeps track of used attributes.
Node GetOutputAttribute(Tegra::Shader::Attribute::Index index, u64 element, Node buffer);
/// Generates a node representing an internal flag
Node GetInternalFlag(InternalFlag flag, bool negated = false);
Node GetInternalFlag(InternalFlag flag, bool negated = false) const;
/// Generates a node representing a local memory address
Node GetLocalMemory(Node address);
/// Generates a node representing a shared memory address
@ -272,9 +284,6 @@ private:
/// Returns a predicate combiner operation
OperationCode GetPredicateCombiner(Tegra::Shader::PredOperation operation);
/// Returns a condition code evaluated from internal flags
Node GetConditionCode(Tegra::Shader::ConditionCode cc);
/// Accesses a texture sampler
const Sampler& GetSampler(const Tegra::Shader::Sampler& sampler,
Tegra::Shader::TextureType type, bool is_array, bool is_shadow);
@ -358,7 +367,7 @@ private:
const ProgramCode& program_code;
const u32 main_offset;
const std::size_t program_size;
bool disable_flow_stack{};
bool decompiled{};
u32 coverage_begin{};
u32 coverage_end{};