Files
P3DS-test/src/core/PICA/shader_decompiler.cpp
2024-07-24 02:03:29 +03:00

309 lines
9.2 KiB
C++

#include "PICA/shader_decompiler.hpp"
#include "config.hpp"
using namespace PICA;
using namespace PICA::ShaderGen;
using namespace Helpers;
using Function = ControlFlow::Function;
using ExitMode = Function::ExitMode;
void ControlFlow::analyze(const PICAShader& shader, u32 entrypoint) {
analysisFailed = false;
const Function* function = addFunction(shader, entrypoint, PICAShader::maxInstructionCount);
if (function == nullptr) {
analysisFailed = true;
}
}
ExitMode ControlFlow::analyzeFunction(const PICAShader& shader, u32 start, u32 end, Function::Labels& labels) {
// Initialize exit mode to unknown by default, in order to detect things like unending loops
auto [it, inserted] = exitMap.emplace(AddressRange(start, end), ExitMode::Unknown);
// Function has already been analyzed and is in the map so it wasn't added, don't analyze again
if (!inserted) {
return it->second;
}
// Make sure not to go out of bounds on the shader
for (u32 pc = start; pc < PICAShader::maxInstructionCount && pc != end; pc++) {
const u32 instruction = shader.loadedShader[pc];
const u32 opcode = instruction >> 26;
switch (opcode) {
case ShaderOpcodes::JMPC: Helpers::panic("Unimplemented control flow operation (JMPC)");
case ShaderOpcodes::JMPU: Helpers::panic("Unimplemented control flow operation (JMPU)");
case ShaderOpcodes::IFU: Helpers::panic("Unimplemented control flow operation (IFU)");
case ShaderOpcodes::IFC: Helpers::panic("Unimplemented control flow operation (IFC)");
case ShaderOpcodes::CALL: Helpers::panic("Unimplemented control flow operation (CALL)");
case ShaderOpcodes::CALLC: Helpers::panic("Unimplemented control flow operation (CALLC)");
case ShaderOpcodes::CALLU: Helpers::panic("Unimplemented control flow operation (CALLU)");
case ShaderOpcodes::LOOP: Helpers::panic("Unimplemented control flow operation (LOOP)");
case ShaderOpcodes::END: it->second = ExitMode::AlwaysEnd; return it->second;
default: break;
}
}
// A function without control flow instructions will always reach its "return point" and return
return ExitMode::AlwaysReturn;
}
void ShaderDecompiler::compileRange(const AddressRange& range) {
u32 pc = range.start;
const u32 end = range.end >= range.start ? range.end : PICAShader::maxInstructionCount;
bool finished = false;
while (pc < end && !finished) {
compileInstruction(pc, finished);
}
}
const Function* ShaderDecompiler::findFunction(const AddressRange& range) {
for (const Function& func : controlFlow.functions) {
if (range.start == func.start && range.end == func.end) {
return &func;
}
}
return nullptr;
}
void ShaderDecompiler::writeAttributes() {
decompiledShader += R"(
layout(location = 0) in vec4 inputs[8];
layout(std140) uniform PICAShaderUniforms {
vec4 uniform_float[96];
uvec4 uniform_int;
uint uniform_bool;
};
vec4 temp_registers[16];
vec4 dummy_vec = vec4(0.0);
)";
decompiledShader += "\n";
}
std::string ShaderDecompiler::decompile() {
controlFlow.analyze(shader, entrypoint);
if (controlFlow.analysisFailed) {
return "";
}
decompiledShader = "";
switch (api) {
case API::GL: decompiledShader += "#version 410 core\n"; break;
case API::GLES: decompiledShader += "#version 300 es\n"; break;
default: break;
}
writeAttributes();
if (config.accurateShaderMul) {
// Safe multiplication handler from Citra: Handles the PICA's 0 * inf = 0 edge case
decompiledShader += R"(
vec4 safe_mul(vec4 a, vec4 b) {
vec4 res = a * b;
return mix(res, mix(mix(vec4(0.0), res, isnan(rhs)), product, isnan(lhs)), isnan(res));
}
)";
}
// Forward declare every generated function first so that we can easily call anything from anywhere.
for (auto& func : controlFlow.functions) {
decompiledShader += func.getForwardDecl();
}
decompiledShader += "void pica_shader_main() {\n";
AddressRange mainFunctionRange(entrypoint, PICAShader::maxInstructionCount);
callFunction(*findFunction(mainFunctionRange));
decompiledShader += "}\n";
for (auto& func : controlFlow.functions) {
if (func.outLabels.size() > 0) {
Helpers::panic("Function with out labels");
}
decompiledShader += "void " + func.getIdentifier() + "() {\n";
compileRange(AddressRange(func.start, func.end));
decompiledShader += "}\n";
}
return decompiledShader;
}
std::string ShaderDecompiler::getSource(u32 source, [[maybe_unused]] u32 index) const {
if (source < 0x10) {
return "inputs[" + std::to_string(source) + "]";
} else if (source < 0x20) {
return "temp_registers[" + std::to_string(source - 0x10) + "]";
} else {
const usize floatIndex = (source - 0x20) & 0x7f;
if (floatIndex >= 96) [[unlikely]] {
return "dummy_vec";
}
return "uniform_float[" + std::to_string(floatIndex) + "]";
}
}
std::string ShaderDecompiler::getDest(u32 dest) const {
if (dest < 0x10) {
return "output_registers[" + std::to_string(dest) + "]";
} else if (dest < 0x20) {
return "temp_registers[" + std::to_string(dest - 0x10) + "]";
} else {
return "dummy_vec";
}
}
std::string ShaderDecompiler::getSwizzlePattern(u32 swizzle) const {
static constexpr std::array<char, 4> names = {'x', 'y', 'z', 'w'};
std::string ret(". ");
for (int i = 0; i < 4; i++) {
ret[3 - i + 1] = names[swizzle & 0x3];
swizzle >>= 2;
}
return ret;
}
std::string ShaderDecompiler::getDestSwizzle(u32 destinationMask) const {
std::string ret = ".";
if (destinationMask & 0b1000) {
ret += "x";
}
if (destinationMask & 0b100) {
ret += "y";
}
if (destinationMask & 0b10) {
ret += "z";
}
if (destinationMask & 0b1) {
ret += "w";
}
return ret;
}
void ShaderDecompiler::setDest(u32 operandDescriptor, const std::string& dest, const std::string& value) {
u32 destinationMask = operandDescriptor & 0xF;
std::string destSwizzle = getDestSwizzle(destinationMask);
// We subtract 1 for the "." character of the swizzle descriptor
u32 writtenLaneCount = destSwizzle.size() - 1;
// All lanes are masked out, so the operation is a nop.
if (writtenLaneCount == 0) {
return;
}
decompiledShader += dest + destSwizzle + " = ";
if (writtenLaneCount == 1) {
decompiledShader += "float(" + value + ");\n";
} else {
decompiledShader += "vec" + std::to_string(writtenLaneCount) + "(" + value + ");\n";
}
}
void ShaderDecompiler::compileInstruction(u32& pc, bool& finished) {
const u32 instruction = shader.loadedShader[pc];
const u32 opcode = instruction >> 26;
if (usesCommonEncoding(instruction)) {
const u32 operandDescriptor = shader.operandDescriptors[instruction & 0x7f];
const bool invertSources = (opcode == ShaderOpcodes::SLTI || opcode == ShaderOpcodes::SGEI || opcode == ShaderOpcodes::DPHI);
// src1 and src2 indexes depend on whether this is one of the inverting instructions or not
const u32 src1Index = invertSources ? getBits<14, 5>(instruction) : getBits<12, 7>(instruction);
const u32 src2Index = invertSources ? getBits<7, 7>(instruction) : getBits<7, 5>(instruction);
const u32 idx = getBits<19, 2>(instruction);
const u32 destIndex = getBits<21, 5>(instruction);
const bool negate1 = (getBit<4>(operandDescriptor)) != 0;
const u32 swizzle1 = getBits<5, 8>(operandDescriptor);
const bool negate2 = (getBit<13>(operandDescriptor)) != 0;
const u32 swizzle2 = getBits<14, 8>(operandDescriptor);
std::string src1 = negate1 ? "-" : "";
src1 += getSource(src1Index, invertSources ? 0 : idx);
src1 += getSwizzlePattern(swizzle1);
std::string src2 = negate2 ? "-" : "";
src2 += getSource(src2Index, invertSources ? idx : 0);
src2 += getSwizzlePattern(swizzle2);
std::string dest = getDest(destIndex);
if (idx != 0) {
Helpers::panic("GLSL recompiler: Indexed instruction");
}
if (invertSources) {
Helpers::panic("GLSL recompiler: Inverted instruction");
}
switch (opcode) {
case ShaderOpcodes::DP4: setDest(operandDescriptor, dest, "vec4(dot(" + src1 + ", " + src2 + "))"); break;
case ShaderOpcodes::MOV: setDest(operandDescriptor, dest, src1); break;
default: Helpers::panic("GLSL recompiler: Unknown common opcode: %X", opcode); break;
}
} else {
switch (opcode) {
case ShaderOpcodes::END: finished = true; return;
default: Helpers::panic("GLSL recompiler: Unknown opcode: %X", opcode); break;
}
}
pc++;
}
bool ShaderDecompiler::usesCommonEncoding(u32 instruction) const {
const u32 opcode = instruction >> 26;
switch (opcode) {
case ShaderOpcodes::ADD:
case ShaderOpcodes::CMP1:
case ShaderOpcodes::CMP2:
case ShaderOpcodes::MUL:
case ShaderOpcodes::MIN:
case ShaderOpcodes::MAX:
case ShaderOpcodes::FLR:
case ShaderOpcodes::DP3:
case ShaderOpcodes::DP4:
case ShaderOpcodes::DPH:
case ShaderOpcodes::DPHI:
case ShaderOpcodes::LG2:
case ShaderOpcodes::EX2:
case ShaderOpcodes::RCP:
case ShaderOpcodes::RSQ:
case ShaderOpcodes::MOV:
case ShaderOpcodes::MOVA:
case ShaderOpcodes::SLT:
case ShaderOpcodes::SLTI:
case ShaderOpcodes::SGE:
case ShaderOpcodes::SGEI: return true;
default: return false;
}
}
void ShaderDecompiler::callFunction(const Function& function) { decompiledShader += function.getCallStatement() + ";\n"; }
std::string ShaderGen::decompileShader(PICAShader& shader, EmulatorConfig& config, u32 entrypoint, API api, Language language) {
ShaderDecompiler decompiler(shader, config, entrypoint, api, language);
return decompiler.decompile();
}