// Copyright 2018 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <map>
#include <set>
#include <string>
#include <string_view>
#include "common/assert.h"
#include "common/common_types.h"
#include "video_core/engines/shader_bytecode.h"
#include "video_core/renderer_opengl/gl_shader_decompiler.h"
namespace GLShader {
namespace Decompiler {
using Tegra::Shader::Attribute;
using Tegra::Shader::Instruction;
using Tegra::Shader::OpCode;
using Tegra::Shader::Register;
using Tegra::Shader::Sampler;
using Tegra::Shader::SubOp;
using Tegra::Shader::Uniform;
constexpr u32 PROGRAM_END = MAX_PROGRAM_CODE_LENGTH;
class DecompileFail : public std::runtime_error {
public:
using std::runtime_error::runtime_error;
};
/// Describes the behaviour of code path of a given entry point and a return point.
enum class ExitMethod {
Undetermined, ///< Internal value. Only occur when analyzing JMP loop.
AlwaysReturn, ///< All code paths reach the return point.
Conditional, ///< Code path reaches the return point or an END instruction conditionally.
AlwaysEnd, ///< All code paths reach a END instruction.
};
/// A subroutine is a range of code refereced by a CALL, IF or LOOP instruction.
struct Subroutine {
/// Generates a name suitable for GLSL source code.
std::string GetName() const {
return "sub_" + std::to_string(begin) + '_' + std::to_string(end);
}
u32 begin; ///< Entry point of the subroutine.
u32 end; ///< Return point of the subroutine.
ExitMethod exit_method; ///< Exit method of the subroutine.
std::set<u32> labels; ///< Addresses refereced by JMP instructions.
bool operator<(const Subroutine& rhs) const {
return std::tie(begin, end) < std::tie(rhs.begin, rhs.end);
}
};
/// Analyzes shader code and produces a set of subroutines.
class ControlFlowAnalyzer {
public:
ControlFlowAnalyzer(const ProgramCode& program_code, u32 main_offset)
: program_code(program_code) {
// Recursively finds all subroutines.
const Subroutine& program_main = AddSubroutine(main_offset, PROGRAM_END);
if (program_main.exit_method != ExitMethod::AlwaysEnd)
throw DecompileFail("Program does not always end");
}
std::set<Subroutine> GetSubroutines() {
return std::move(subroutines);
}
private:
const ProgramCode& program_code;
std::set<Subroutine> subroutines;
std::map<std::pair<u32, u32>, ExitMethod> exit_method_map;
/// Adds and analyzes a new subroutine if it is not added yet.
const Subroutine& AddSubroutine(u32 begin, u32 end) {
auto iter = subroutines.find(Subroutine{begin, end});
if (iter != subroutines.end())
return *iter;
Subroutine subroutine{begin, end};
subroutine.exit_method = Scan(begin, end, subroutine.labels);
if (subroutine.exit_method == ExitMethod::Undetermined)
throw DecompileFail("Recursive function detected");
return *subroutines.insert(std::move(subroutine)).first;
}
/// Scans a range of code for labels and determines the exit method.
ExitMethod Scan(u32 begin, u32 end, std::set<u32>& labels) {
auto [iter, inserted] =
exit_method_map.emplace(std::make_pair(begin, end), ExitMethod::Undetermined);
ExitMethod& exit_method = iter->second;
if (!inserted)
return exit_method;
for (u32 offset = begin; offset != end && offset != PROGRAM_END; ++offset) {
if (const auto opcode = OpCode::Decode({program_code[offset]})) {
switch (opcode->GetId()) {
case OpCode::Id::EXIT: {
return exit_method = ExitMethod::AlwaysEnd;
}
}
}
}
return exit_method = ExitMethod::AlwaysReturn;
}
};
class ShaderWriter {
public:
void AddLine(std::string_view text) {
DEBUG_ASSERT(scope >= 0);
if (!text.empty()) {
AppendIndentation();
}
shader_source += text;
AddNewLine();
}
void AddLine(char character) {
DEBUG_ASSERT(scope >= 0);
AppendIndentation();
shader_source += character;
AddNewLine();
}
void AddNewLine() {
DEBUG_ASSERT(scope >= 0);
shader_source += '\n';
}
std::string GetResult() {
return std::move(shader_source);
}
int scope = 0;
private:
void AppendIndentation() {
shader_source.append(static_cast<size_t>(scope) * 4, ' ');
}
std::string shader_source;
};
/**
* Represents an emulated shader register, used to track the state of that register for emulation
* with GLSL. At this time, a register can be used as a float or an integer. This class is used for
* bookkeeping within the GLSL program.
*/
class GLSLRegister {
public:
enum class Type {
Float,
Integer,
UnsignedInteger,
};
GLSLRegister(size_t index, ShaderWriter& shader) : index{index}, shader{shader} {}
/// Gets the GLSL type string for a register
static std::string GetTypeString(Type type) {
switch (type) {
case Type::Float:
return "float";
case Type::Integer:
return "int";
case Type::UnsignedInteger:
return "uint";
}
UNREACHABLE();
return {};
}
/// Gets the GLSL register prefix string, used for declarations and referencing
static std::string GetPrefixString(Type type) {
return "reg_" + GetTypeString(type) + '_';
}
/// Returns a GLSL string representing the current state of the register
const std::string GetActiveString() {
declr_type.insert(active_type);
return GetPrefixString(active_type) + std::to_string(index);
}
/// Returns true if the active type is a float
bool IsFloat() const {
return active_type == Type::Float;
}
/// Returns true if the active type is an integer
bool IsInteger() const {
return active_type == Type::Integer;
}
/// Returns the index of the register
size_t GetIndex() const {
return index;
}
/// Returns a set of the declared types of the register
const std::set<Type>& DeclaredTypes() const {
return declr_type;
}
private:
const size_t index;
const std::string float_str;
const std::string integer_str;
ShaderWriter& shader;
Type active_type{Type::Float};
std::set<Type> declr_type;
};
/**
* Used to manage shader registers that are emulated with GLSL. This class keeps track of the state
* of all registers (e.g. whether they are currently being used as Floats or Integers), and
* generates the necessary GLSL code to perform conversions as needed. This class is used for
* bookkeeping within the GLSL program.
*/
class GLSLRegisterManager {
public:
GLSLRegisterManager(ShaderWriter& shader, ShaderWriter& declarations,
const Maxwell3D::Regs::ShaderStage& stage)
: shader{shader}, declarations{declarations}, stage{stage} {
BuildRegisterList();
}
/**
* Gets a register as an float.
* @param reg The register to get.
* @param elem The element to use for the operation.
* @returns GLSL string corresponding to the register as a float.
*/
std::string GetRegisterAsFloat(const Register& reg, unsigned elem = 0) {
ASSERT(regs[reg].IsFloat());
return GetRegister(reg, elem);
}
/**
* Gets a register as an integer.
* @param reg The register to get.
* @param elem The element to use for the operation.
* @param is_signed Whether to get the register as a signed (or unsigned) integer.
* @returns GLSL string corresponding to the register as an integer.
*/
std::string GetRegisterAsInteger(const Register& reg, unsigned elem = 0,
bool is_signed = true) {
const std::string func = GetGLSLConversionFunc(
GLSLRegister::Type::Float,
is_signed ? GLSLRegister::Type::Integer : GLSLRegister::Type::UnsignedInteger);
return func + '(' + GetRegister(reg, elem) + ')';
}
/**
* Writes code that does a register assignment to float value operation.
* @param reg The destination register to use.
* @param elem The element to use for the operation.
* @param value The code representing the value to assign.
* @param dest_num_components Number of components in the destination.
* @param value_num_components Number of components in the value.
* @param is_abs Optional, when True, applies absolute value to output.
* @param dest_elem Optional, the destination element to use for the operation.
*/
void SetRegisterToFloat(const Register& reg, u64 elem, const std::string& value,
u64 dest_num_components, u64 value_num_components, bool is_abs = false,
u64 dest_elem = 0) {
SetRegister(reg, elem, value, dest_num_components, value_num_components, is_abs, dest_elem);
}
/**
* Writes code that does a register assignment to integer value operation.
* @param reg The destination register to use.
* @param elem The element to use for the operation.
* @param value The code representing the value to assign.
* @param dest_num_components Number of components in the destination.
* @param value_num_components Number of components in the value.
* @param is_abs Optional, when True, applies absolute value to output.
* @param dest_elem Optional, the destination element to use for the operation.
*/
void SetRegisterToInteger(const Register& reg, bool is_signed, u64 elem,
const std::string& value, u64 dest_num_components,
u64 value_num_components, bool is_abs = false, u64 dest_elem = 0) {
const std::string func = GetGLSLConversionFunc(
is_signed ? GLSLRegister::Type::Integer : GLSLRegister::Type::UnsignedInteger,
GLSLRegister::Type::Float);
SetRegister(reg, elem, func + '(' + value + ')', dest_num_components, value_num_components,
is_abs, dest_elem);
}
/**
* Writes code that does a register assignment to input attribute operation. Input attributes
* are stored as floats, so this may require conversion.
* @param reg The destination register to use.
* @param elem The element to use for the operation.
* @param attribute The input attibute to use as the source value.
*/
void SetRegisterToInputAttibute(const Register& reg, u64 elem, Attribute::Index attribute) {
std::string dest = GetRegisterAsFloat(reg);
std::string src = GetInputAttribute(attribute) + GetSwizzle(elem);
if (regs[reg].IsFloat()) {
shader.AddLine(dest + " = " + src + ';');
} else if (regs[reg].IsInteger()) {
shader.AddLine(dest + " = floatBitsToInt(" + src + ");");
} else {
UNREACHABLE();
}
}
/**
* Writes code that does a output attribute assignment to register operation. Output attributes
* are stored as floats, so this may require conversion.
* @param attribute The destination output attribute.
* @param elem The element to use for the operation.
* @param reg The register to use as the source value.
*/
void SetOutputAttributeToRegister(Attribute::Index attribute, u64 elem, const Register& reg) {
std::string dest = GetOutputAttribute(attribute) + GetSwizzle(elem);
std::string src = GetRegisterAsFloat(reg);
ASSERT_MSG(regs[reg].IsFloat(), "Output attributes must be set to a float");
shader.AddLine(dest + " = " + src + ';');
}
/// Generates code representing a uniform (C buffer) register.
std::string GetUniform(const Uniform& uniform, const Register& dest_reg) {
declr_const_buffers[uniform.index].MarkAsUsed(static_cast<unsigned>(uniform.index),
static_cast<unsigned>(uniform.offset), stage);
std::string value =
'c' + std::to_string(uniform.index) + '[' + std::to_string(uniform.offset) + ']';
if (regs[dest_reg].IsFloat()) {
return value;
} else if (regs[dest_reg].IsInteger()) {
return "floatBitsToInt(" + value + ')';
} else {
UNREACHABLE();
}
}
/// Add declarations for registers
void GenerateDeclarations() {
for (const auto& reg : regs) {
for (const auto& type : reg.DeclaredTypes()) {
declarations.AddLine(GLSLRegister::GetTypeString(type) + ' ' +
GLSLRegister::GetPrefixString(type) +
std::to_string(reg.GetIndex()) + " = 0;");
}
}
declarations.AddNewLine();
for (const auto& index : declr_input_attribute) {
// TODO(bunnei): Use proper number of elements for these
declarations.AddLine("layout(location = " +
std::to_string(static_cast<u32>(index) -
static_cast<u32>(Attribute::Index::Attribute_0)) +
") in vec4 " + GetInputAttribute(index) + ';');
}
declarations.AddNewLine();
for (const auto& index : declr_output_attribute) {
// TODO(bunnei): Use proper number of elements for these
declarations.AddLine("layout(location = " +
std::to_string(static_cast<u32>(index) -
static_cast<u32>(Attribute::Index::Attribute_0)) +
") out vec4 " + GetOutputAttribute(index) + ';');
}
declarations.AddNewLine();
unsigned const_buffer_layout = 0;
for (const auto& entry : GetConstBuffersDeclarations()) {
declarations.AddLine("layout(std430) buffer " + entry.GetName());
declarations.AddLine('{');
declarations.AddLine(" float c" + std::to_string(entry.GetIndex()) + "[];");
declarations.AddLine("};");
declarations.AddNewLine();
++const_buffer_layout;
}
declarations.AddNewLine();
}
/// Returns a list of constant buffer declarations
std::vector<ConstBufferEntry> GetConstBuffersDeclarations() const {
std::vector<ConstBufferEntry> result;
std::copy_if(declr_const_buffers.begin(), declr_const_buffers.end(),
std::back_inserter(result), [](const auto& entry) { return entry.IsUsed(); });
return result;
}
private:
/// Build GLSL conversion function, e.g. floatBitsToInt, intBitsToFloat, etc.
const std::string GetGLSLConversionFunc(GLSLRegister::Type src, GLSLRegister::Type dest) const {
const std::string src_type = GLSLRegister::GetTypeString(src);
std::string dest_type = GLSLRegister::GetTypeString(dest);
dest_type[0] = toupper(dest_type[0]);
return src_type + "BitsTo" + dest_type;
}
/// Generates code representing a temporary (GPR) register.
std::string GetRegister(const Register& reg, unsigned elem) {
if (reg == Register::ZeroIndex) {
return "0";
}
return regs[reg.GetSwizzledIndex(elem)].GetActiveString();
}
/**
* Writes code that does a register assignment to value operation.
* @param reg The destination register to use.
* @param elem The element to use for the operation.
* @param value The code representing the value to assign.
* @param dest_num_components Number of components in the destination.
* @param value_num_components Number of components in the value.
* @param is_abs Optional, when True, applies absolute value to output.
* @param dest_elem Optional, the destination element to use for the operation.
*/
void SetRegister(const Register& reg, u64 elem, const std::string& value,
u64 dest_num_components, u64 value_num_components, bool is_abs,
u64 dest_elem) {
std::string dest = GetRegister(reg, dest_elem);
if (dest_num_components > 1) {
dest += GetSwizzle(elem);
}
std::string src = '(' + value + ')';
if (value_num_components > 1) {
src += GetSwizzle(elem);
}
src = is_abs ? "abs(" + src + ')' : src;
shader.AddLine(dest + " = " + src + ';');
}
/// Build the GLSL register list.
void BuildRegisterList() {
for (size_t index = 0; index < Register::NumRegisters; ++index) {
regs.emplace_back(index, shader);
}
}
/// Generates code representing an input attribute register.
std::string GetInputAttribute(Attribute::Index attribute) {
switch (attribute) {
case Attribute::Index::Position:
return "position";
default:
const u32 index{static_cast<u32>(attribute) -
static_cast<u32>(Attribute::Index::Attribute_0)};
if (attribute >= Attribute::Index::Attribute_0) {
declr_input_attribute.insert(attribute);
return "input_attribute_" + std::to_string(index);
}
NGLOG_CRITICAL(HW_GPU, "Unhandled input attribute: {}", index);
UNREACHABLE();
}
}
/// Generates code representing an output attribute register.
std::string GetOutputAttribute(Attribute::Index attribute) {
switch (attribute) {
case Attribute::Index::Position:
return "position";
default:
const u32 index{static_cast<u32>(attribute) -
static_cast<u32>(Attribute::Index::Attribute_0)};
if (attribute >= Attribute::Index::Attribute_0) {
declr_output_attribute.insert(attribute);
return "output_attribute_" + std::to_string(index);
}
NGLOG_CRITICAL(HW_GPU, "Unhandled output attribute: {}", index);
UNREACHABLE();
}
}
/// Generates code to use for a swizzle operation.
static std::string GetSwizzle(u64 elem) {
ASSERT(elem <= 3);
std::string swizzle = ".";
swizzle += "xyzw"[elem];
return swizzle;
}
ShaderWriter& shader;
ShaderWriter& declarations;
std::vector<GLSLRegister> regs;
std::set<Attribute::Index> declr_input_attribute;
std::set<Attribute::Index> declr_output_attribute;
std::array<ConstBufferEntry, Maxwell3D::Regs::MaxConstBuffers> declr_const_buffers;
const Maxwell3D::Regs::ShaderStage& stage;
};
class GLSLGenerator {
public:
GLSLGenerator(const std::set<Subroutine>& subroutines, const ProgramCode& program_code,
u32 main_offset, Maxwell3D::Regs::ShaderStage stage)
: subroutines(subroutines), program_code(program_code), main_offset(main_offset),
stage(stage) {
Generate();
}
std::string GetShaderCode() {
return declarations.GetResult() + shader.GetResult();
}
/// Returns entries in the shader that are useful for external functions
ShaderEntries GetEntries() const {
return {regs.GetConstBuffersDeclarations()};
}
private:
/// Gets the Subroutine object corresponding to the specified address.
const Subroutine& GetSubroutine(u32 begin, u32 end) const {
auto iter = subroutines.find(Subroutine{begin, end});
ASSERT(iter != subroutines.end());
return *iter;
}
/// Generates code representing a 19-bit immediate value
static std::string GetImmediate19(const Instruction& instr) {
return std::to_string(instr.alu.GetImm20_19());
}
/// Generates code representing a 32-bit immediate value
static std::string GetImmediate32(const Instruction& instr) {
return std::to_string(instr.alu.GetImm20_32());
}
/// Generates code representing a texture sampler.
std::string GetSampler(const Sampler& sampler) const {
// TODO(Subv): Support more than just texture sampler 0
ASSERT_MSG(sampler.index == Sampler::Index::Sampler_0, "unsupported");
const unsigned index{static_cast<unsigned>(sampler.index.Value()) -
static_cast<unsigned>(Sampler::Index::Sampler_0)};
return "tex[" + std::to_string(index) + ']';
}
/**
* Adds code that calls a subroutine.
* @param subroutine the subroutine to call.
*/
void CallSubroutine(const Subroutine& subroutine) {
if (subroutine.exit_method == ExitMethod::AlwaysEnd) {
shader.AddLine(subroutine.GetName() + "();");
shader.AddLine("return true;");
} else if (subroutine.exit_method == ExitMethod::Conditional) {
shader.AddLine("if (" + subroutine.GetName() + "()) { return true; }");
} else {
shader.AddLine(subroutine.GetName() + "();");
}
}
/*
* Writes code that assigns a predicate boolean variable.
* @param pred The id of the predicate to write to.
* @param value The expression value to assign to the predicate.
*/
void SetPredicate(u64 pred, const std::string& value) {
using Tegra::Shader::Pred;
// Can't assign to the constant predicate.
ASSERT(pred != static_cast<u64>(Pred::UnusedIndex));
std::string variable = 'p' + std::to_string(pred);
shader.AddLine(variable + " = " + value + ';');
declr_predicates.insert(std::move(variable));
}
/*
* Returns the condition to use in the 'if' for a predicated instruction.
* @param instr Instruction to generate the if condition for.
* @returns string containing the predicate condition.
*/
std::string GetPredicateCondition(u64 index, bool negate) const {
using Tegra::Shader::Pred;
std::string variable;
// Index 7 is used as an 'Always True' condition.
if (index == static_cast<u64>(Pred::UnusedIndex))
variable = "true";
else
variable = 'p' + std::to_string(index);
if (negate) {
return "!(" + variable + ')';
}
return variable;
}
/**
* Returns the comparison string to use to compare two values in the 'set' family of
* instructions.
* @params condition The condition used in the 'set'-family instruction.
* @returns String corresponding to the GLSL operator that matches the desired comparison.
*/
std::string GetPredicateComparison(Tegra::Shader::PredCondition condition) const {
using Tegra::Shader::PredCondition;
static const std::unordered_map<PredCondition, const char*> PredicateComparisonStrings = {
{PredCondition::LessThan, "<"}, {PredCondition::Equal, "=="},
{PredCondition::LessEqual, "<="}, {PredCondition::GreaterThan, ">"},
{PredCondition::GreaterEqual, ">="},
};
auto comparison = PredicateComparisonStrings.find(condition);
ASSERT_MSG(comparison != PredicateComparisonStrings.end(),
"Unknown predicate comparison operation");
return comparison->second;
}
/**
* Returns the operator string to use to combine two predicates in the 'setp' family of
* instructions.
* @params operation The operator used in the 'setp'-family instruction.
* @returns String corresponding to the GLSL operator that matches the desired operator.
*/
std::string GetPredicateCombiner(Tegra::Shader::PredOperation operation) const {
using Tegra::Shader::PredOperation;
static const std::unordered_map<PredOperation, const char*> PredicateOperationStrings = {
{PredOperation::And, "&&"},
{PredOperation::Or, "||"},
{PredOperation::Xor, "^^"},
};
auto op = PredicateOperationStrings.find(operation);
ASSERT_MSG(op != PredicateOperationStrings.end(), "Unknown predicate operation");
return op->second;
}
/*
* Returns whether the instruction at the specified offset is a 'sched' instruction.
* Sched instructions always appear before a sequence of 3 instructions.
*/
bool IsSchedInstruction(u32 offset) const {
// sched instructions appear once every 4 instructions.
static constexpr size_t SchedPeriod = 4;
u32 absolute_offset = offset - main_offset;
return (absolute_offset % SchedPeriod) == 0;
}
/**
* Compiles a single instruction from Tegra to GLSL.
* @param offset the offset of the Tegra shader instruction.
* @return the offset of the next instruction to execute. Usually it is the current offset
* + 1. If the current instruction always terminates the program, returns PROGRAM_END.
*/
u32 CompileInstr(u32 offset) {
// Ignore sched instructions when generating code.
if (IsSchedInstruction(offset)) {
return offset + 1;
}
const Instruction instr = {program_code[offset]};
const auto opcode = OpCode::Decode(instr);
// Decoding failure
if (!opcode) {
NGLOG_CRITICAL(HW_GPU, "Unhandled instruction: {0:x}", instr.value);
UNREACHABLE();
}
shader.AddLine("// " + std::to_string(offset) + ": " + opcode->GetName());
using Tegra::Shader::Pred;
ASSERT_MSG(instr.pred.full_pred != Pred::NeverExecute,
"NeverExecute predicate not implemented");
if (instr.pred.pred_index != static_cast<u64>(Pred::UnusedIndex)) {
shader.AddLine("if (" +
GetPredicateCondition(instr.pred.pred_index, instr.negate_pred != 0) +
')');
shader.AddLine('{');
++shader.scope;
}
switch (opcode->GetType()) {
case OpCode::Type::Arithmetic: {
std::string op_a = instr.alu.negate_a ? "-" : "";
op_a += regs.GetRegisterAsFloat(instr.gpr8);
if (instr.alu.abs_a) {
op_a = "abs(" + op_a + ')';
}
std::string op_b = instr.alu.negate_b ? "-" : "";
if (instr.is_b_imm) {
op_b += GetImmediate19(instr);
} else {
if (instr.is_b_gpr) {
op_b += regs.GetRegisterAsFloat(instr.gpr20);
} else {
op_b += regs.GetUniform(instr.uniform, instr.gpr0);
}
}
if (instr.alu.abs_b) {
op_b = "abs(" + op_b + ')';
}
switch (opcode->GetId()) {
case OpCode::Id::MOV_C:
case OpCode::Id::MOV_R: {
regs.SetRegisterToFloat(instr.gpr0, 0, op_b, 1, 1);
break;
}
case OpCode::Id::MOV32_IMM: {
// mov32i doesn't have abs or neg bits.
regs.SetRegisterToFloat(instr.gpr0, 0, GetImmediate32(instr), 1, 1);
break;
}
case OpCode::Id::FMUL_C:
case OpCode::Id::FMUL_R:
case OpCode::Id::FMUL_IMM: {
regs.SetRegisterToFloat(instr.gpr0, 0, op_a + " * " + op_b, 1, 1, instr.alu.abs_d);
break;
}
case OpCode::Id::FMUL32_IMM: {
// fmul32i doesn't have abs or neg bits.
regs.SetRegisterToFloat(
instr.gpr0, 0,
regs.GetRegisterAsFloat(instr.gpr8) + " * " + GetImmediate32(instr), 1, 1);
break;
}
case OpCode::Id::FADD_C:
case OpCode::Id::FADD_R:
case OpCode::Id::FADD_IMM: {
regs.SetRegisterToFloat(instr.gpr0, 0, op_a + " + " + op_b, 1, 1, instr.alu.abs_d);
break;
}
case OpCode::Id::MUFU: {
switch (instr.sub_op) {
case SubOp::Cos:
regs.SetRegisterToFloat(instr.gpr0, 0, "cos(" + op_a + ')', 1, 1,
instr.alu.abs_d);
break;
case SubOp::Sin:
regs.SetRegisterToFloat(instr.gpr0, 0, "sin(" + op_a + ')', 1, 1,
instr.alu.abs_d);
break;
case SubOp::Ex2:
regs.SetRegisterToFloat(instr.gpr0, 0, "exp2(" + op_a + ')', 1, 1,
instr.alu.abs_d);
break;
case SubOp::Lg2:
regs.SetRegisterToFloat(instr.gpr0, 0, "log2(" + op_a + ')', 1, 1,
instr.alu.abs_d);
break;
case SubOp::Rcp:
regs.SetRegisterToFloat(instr.gpr0, 0, "1.0 / " + op_a, 1, 1, instr.alu.abs_d);
break;
case SubOp::Rsq:
regs.SetRegisterToFloat(instr.gpr0, 0, "inversesqrt(" + op_a + ')', 1, 1,
instr.alu.abs_d);
break;
case SubOp::Min:
regs.SetRegisterToFloat(instr.gpr0, 0, "min(" + op_a + "," + op_b + ')', 1, 1,
instr.alu.abs_d);
break;
default:
NGLOG_CRITICAL(HW_GPU, "Unhandled MUFU sub op: {0:x}",
static_cast<unsigned>(instr.sub_op.Value()));
UNREACHABLE();
}
break;
}
case OpCode::Id::FMNMX: {
std::string condition =
GetPredicateCondition(instr.alu.fmnmx.pred, instr.alu.fmnmx.negate_pred != 0);
std::string parameters = op_a + ',' + op_b;
regs.SetRegisterToFloat(instr.gpr0, 0,
'(' + condition + ") ? min(" + parameters + ") : max(" +
parameters + ')',
1, 1);
break;
}
case OpCode::Id::RRO: {
NGLOG_DEBUG(HW_GPU, "Skipping RRO instruction");
break;
}
default: {
NGLOG_CRITICAL(HW_GPU, "Unhandled arithmetic instruction: {}", opcode->GetName());
UNREACHABLE();
}
}
break;
}
case OpCode::Type::Ffma: {
std::string op_a = regs.GetRegisterAsFloat(instr.gpr8);
std::string op_b = instr.ffma.negate_b ? "-" : "";
std::string op_c = instr.ffma.negate_c ? "-" : "";
switch (opcode->GetId()) {
case OpCode::Id::FFMA_CR: {
op_b += regs.GetUniform(instr.uniform, instr.gpr0);
op_c += regs.GetRegisterAsFloat(instr.gpr39);
break;
}
case OpCode::Id::FFMA_RR: {
op_b += regs.GetRegisterAsFloat(instr.gpr20);
op_c += regs.GetRegisterAsFloat(instr.gpr39);
break;
}
case OpCode::Id::FFMA_RC: {
op_b += regs.GetRegisterAsFloat(instr.gpr39);
op_c += regs.GetUniform(instr.uniform, instr.gpr0);
break;
}
case OpCode::Id::FFMA_IMM: {
op_b += GetImmediate19(instr);
op_c += regs.GetRegisterAsFloat(instr.gpr39);
break;
}
default: {
NGLOG_CRITICAL(HW_GPU, "Unhandled FFMA instruction: {}", opcode->GetName());
UNREACHABLE();
}
}
regs.SetRegisterToFloat(instr.gpr0, 0, op_a + " * " + op_b + " + " + op_c, 1, 1);
break;
}
case OpCode::Type::Conversion: {
ASSERT_MSG(instr.conversion.size == Register::Size::Word, "Unimplemented");
ASSERT_MSG(!instr.conversion.selector, "Unimplemented");
ASSERT_MSG(!instr.conversion.negate_a, "Unimplemented");
ASSERT_MSG(!instr.conversion.saturate_a, "Unimplemented");
switch (opcode->GetId()) {
case OpCode::Id::I2I_R:
case OpCode::Id::I2F_R: {
std::string op_a =
regs.GetRegisterAsInteger(instr.gpr20, 0, instr.conversion.is_signed);
if (instr.conversion.abs_a) {
op_a = "abs(" + op_a + ')';
}
regs.SetRegisterToInteger(instr.gpr0, instr.conversion.is_signed, 0, op_a, 1, 1);
break;
}
default: {
NGLOG_CRITICAL(HW_GPU, "Unhandled conversion instruction: {}", opcode->GetName());
UNREACHABLE();
}
}
break;
}
case OpCode::Type::Memory: {
const Attribute::Index attribute = instr.attribute.fmt20.index;
switch (opcode->GetId()) {
case OpCode::Id::LD_A: {
ASSERT_MSG(instr.attribute.fmt20.size == 0, "untested");
regs.SetRegisterToInputAttibute(instr.gpr0, instr.attribute.fmt20.element,
attribute);
break;
}
case OpCode::Id::ST_A: {
ASSERT_MSG(instr.attribute.fmt20.size == 0, "untested");
regs.SetOutputAttributeToRegister(attribute, instr.attribute.fmt20.element,
instr.gpr0);
break;
}
case OpCode::Id::TEXS: {
ASSERT_MSG(instr.attribute.fmt20.size == 4, "untested");
const std::string op_a = regs.GetRegisterAsFloat(instr.gpr8);
const std::string op_b = regs.GetRegisterAsFloat(instr.gpr20);
const std::string sampler = GetSampler(instr.sampler);
const std::string coord = "vec2 coords = vec2(" + op_a + ", " + op_b + ");";
// Add an extra scope and declare the texture coords inside to prevent overwriting
// them in case they are used as outputs of the texs instruction.
shader.AddLine("{");
++shader.scope;
shader.AddLine(coord);
const std::string texture = "texture(" + sampler + ", coords)";
for (unsigned elem = 0; elem < instr.attribute.fmt20.size; ++elem) {
regs.SetRegisterToFloat(instr.gpr0, elem, texture, 1, 4, false, elem);
}
--shader.scope;
shader.AddLine("}");
break;
}
default: {
NGLOG_CRITICAL(HW_GPU, "Unhandled memory instruction: {}", opcode->GetName());
UNREACHABLE();
}
}
break;
}
case OpCode::Type::FloatSetPredicate: {
std::string op_a = instr.fsetp.neg_a ? "-" : "";
op_a += regs.GetRegisterAsFloat(instr.gpr8);
if (instr.fsetp.abs_a) {
op_a = "abs(" + op_a + ')';
}
std::string op_b{};
if (instr.is_b_imm) {
if (instr.fsetp.neg_b) {
// Only the immediate version of fsetp has a neg_b bit.
op_b += '-';
}
op_b += '(' + GetImmediate19(instr) + ')';
} else {
if (instr.is_b_gpr) {
op_b += regs.GetRegisterAsFloat(instr.gpr20);
} else {
op_b += regs.GetUniform(instr.uniform, instr.gpr0);
}
}
if (instr.fsetp.abs_b) {
op_b = "abs(" + op_b + ')';
}
using Tegra::Shader::Pred;
// We can't use the constant predicate as destination.
ASSERT(instr.fsetp.pred3 != static_cast<u64>(Pred::UnusedIndex));
std::string second_pred =
GetPredicateCondition(instr.fsetp.pred39, instr.fsetp.neg_pred != 0);
std::string comparator = GetPredicateComparison(instr.fsetp.cond);
std::string combiner = GetPredicateCombiner(instr.fsetp.op);
std::string predicate = '(' + op_a + ") " + comparator + " (" + op_b + ')';
// Set the primary predicate to the result of Predicate OP SecondPredicate
SetPredicate(instr.fsetp.pred3,
'(' + predicate + ") " + combiner + " (" + second_pred + ')');
if (instr.fsetp.pred0 != static_cast<u64>(Pred::UnusedIndex)) {
// Set the secondary predicate to the result of !Predicate OP SecondPredicate, if
// enabled
SetPredicate(instr.fsetp.pred0,
"!(" + predicate + ") " + combiner + " (" + second_pred + ')');
}
break;
}
case OpCode::Type::FloatSet: {
std::string op_a = instr.fset.neg_a ? "-" : "";
op_a += regs.GetRegisterAsFloat(instr.gpr8);
if (instr.fset.abs_a) {
op_a = "abs(" + op_a + ')';
}
std::string op_b = instr.fset.neg_b ? "-" : "";
if (instr.is_b_imm) {
std::string imm = GetImmediate19(instr);
if (instr.fset.neg_imm)
op_b += "(-" + imm + ')';
else
op_b += imm;
} else {
if (instr.is_b_gpr) {
op_b += regs.GetRegisterAsFloat(instr.gpr20);
} else {
op_b += regs.GetUniform(instr.uniform, instr.gpr0);
}
}
if (instr.fset.abs_b) {
op_b = "abs(" + op_b + ')';
}
// The fset instruction sets a register to 1.0 if the condition is true, and to 0
// otherwise.
std::string second_pred =
GetPredicateCondition(instr.fset.pred39, instr.fset.neg_pred != 0);
std::string comparator = GetPredicateComparison(instr.fset.cond);
std::string combiner = GetPredicateCombiner(instr.fset.op);
std::string predicate = "(((" + op_a + ") " + comparator + " (" + op_b + ")) " +
combiner + " (" + second_pred + "))";
regs.SetRegisterToFloat(instr.gpr0, 0, predicate + " ? 1.0 : 0.0", 1, 1);
break;
}
default: {
switch (opcode->GetId()) {
case OpCode::Id::EXIT: {
ASSERT_MSG(instr.pred.pred_index == static_cast<u64>(Pred::UnusedIndex),
"Predicated exits not implemented");
// Final color output is currently hardcoded to GPR0-3 for fragment shaders
if (stage == Maxwell3D::Regs::ShaderStage::Fragment) {
shader.AddLine("color.r = " + regs.GetRegisterAsFloat(0) + ';');
shader.AddLine("color.g = " + regs.GetRegisterAsFloat(1) + ';');
shader.AddLine("color.b = " + regs.GetRegisterAsFloat(2) + ';');
shader.AddLine("color.a = " + regs.GetRegisterAsFloat(3) + ';');
}
shader.AddLine("return true;");
offset = PROGRAM_END - 1;
break;
}
case OpCode::Id::KIL: {
shader.AddLine("discard;");
break;
}
case OpCode::Id::IPA: {
const auto& attribute = instr.attribute.fmt28;
regs.SetRegisterToInputAttibute(instr.gpr0, attribute.element, attribute.index);
break;
}
default: {
NGLOG_CRITICAL(HW_GPU, "Unhandled instruction: {}", opcode->GetName());
UNREACHABLE();
}
}
break;
}
}
// Close the predicate condition scope.
if (instr.pred.pred_index != static_cast<u64>(Pred::UnusedIndex)) {
--shader.scope;
shader.AddLine('}');
}
return offset + 1;
}
/**
* Compiles a range of instructions from Tegra to GLSL.
* @param begin the offset of the starting instruction.
* @param end the offset where the compilation should stop (exclusive).
* @return the offset of the next instruction to compile. PROGRAM_END if the program
* terminates.
*/
u32 CompileRange(u32 begin, u32 end) {
u32 program_counter;
for (program_counter = begin; program_counter < (begin > end ? PROGRAM_END : end);) {
program_counter = CompileInstr(program_counter);
}
return program_counter;
}
void Generate() {
// Add declarations for all subroutines
for (const auto& subroutine : subroutines) {
shader.AddLine("bool " + subroutine.GetName() + "();");
}
shader.AddNewLine();
// Add the main entry point
shader.AddLine("bool exec_shader() {");
++shader.scope;
CallSubroutine(GetSubroutine(main_offset, PROGRAM_END));
--shader.scope;
shader.AddLine("}\n");
// Add definitions for all subroutines
for (const auto& subroutine : subroutines) {
std::set<u32> labels = subroutine.labels;
shader.AddLine("bool " + subroutine.GetName() + "() {");
++shader.scope;
if (labels.empty()) {
if (CompileRange(subroutine.begin, subroutine.end) != PROGRAM_END) {
shader.AddLine("return false;");
}
} else {
labels.insert(subroutine.begin);
shader.AddLine("uint jmp_to = " + std::to_string(subroutine.begin) + "u;");
shader.AddLine("while (true) {");
++shader.scope;
shader.AddLine("switch (jmp_to) {");
for (auto label : labels) {
shader.AddLine("case " + std::to_string(label) + "u: {");
++shader.scope;
auto next_it = labels.lower_bound(label + 1);
u32 next_label = next_it == labels.end() ? subroutine.end : *next_it;
u32 compile_end = CompileRange(label, next_label);
if (compile_end > next_label && compile_end != PROGRAM_END) {
// This happens only when there is a label inside a IF/LOOP block
shader.AddLine("{ jmp_to = " + std::to_string(compile_end) + "u; break; }");
labels.emplace(compile_end);
}
--shader.scope;
shader.AddLine('}');
}
shader.AddLine("default: return false;");
shader.AddLine('}');
--shader.scope;
shader.AddLine('}');
shader.AddLine("return false;");
}
--shader.scope;
shader.AddLine("}\n");
DEBUG_ASSERT(shader.scope == 0);
}
GenerateDeclarations();
}
/// Add declarations for registers
void GenerateDeclarations() {
regs.GenerateDeclarations();
for (const auto& pred : declr_predicates) {
declarations.AddLine("bool " + pred + " = false;");
}
declarations.AddNewLine();
}
private:
const std::set<Subroutine>& subroutines;
const ProgramCode& program_code;
const u32 main_offset;
Maxwell3D::Regs::ShaderStage stage;
ShaderWriter shader;
ShaderWriter declarations;
GLSLRegisterManager regs{shader, declarations, stage};
// Declarations
std::set<std::string> declr_predicates;
}; // namespace Decompiler
std::string GetCommonDeclarations() {
return "bool exec_shader();";
}
boost::optional<ProgramResult> DecompileProgram(const ProgramCode& program_code, u32 main_offset,
Maxwell3D::Regs::ShaderStage stage) {
try {
auto subroutines = ControlFlowAnalyzer(program_code, main_offset).GetSubroutines();
GLSLGenerator generator(subroutines, program_code, main_offset, stage);
return ProgramResult{generator.GetShaderCode(), generator.GetEntries()};
} catch (const DecompileFail& exception) {
NGLOG_ERROR(HW_GPU, "Shader decompilation failed: {}", exception.what());
}
return boost::none;
}
} // namespace Decompiler
} // namespace GLShader