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[Shader JIT[ Remove shadow stack stuff, remove pushing/popping context pointer

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wheremyfoodat 2023-06-28 22:31:51 +03:00
parent 28e9d87573
commit b027cda648
1 changed files with 10 additions and 21 deletions
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31
src/core/PICA/dynapica/shader_rec_emitter_x64.cpp
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@ -47,18 +47,15 @@ void ShaderEmitter::compile(const PICAShader& shaderUnit) {
align(16);
prologueCb = getCurr<PrologueCallback>();
// We assume arg1 contains the pointer to the PICA state and arg2 a pointer to the code for the entrypoint
push(statePointer); // Back up state pointer to stack. This also aligns rsp to 16 bytes for calls
mov(statePointer, arg1.cvt64()); // Set state pointer to the proper pointer
// If we add integer register allocations they should be pushed here, and the rsp should be properly fixed up
// However most of the PICA is floating point so yeah
// Set state pointer to the proper pointer
// state pointer is volatile, no need to preserve it
mov(statePointer, arg1.cvt64());
// Push a return guard on the stack. This happens due to the way we handle the PICA callstack, by pushing the return PC to stack
// By pushing ffff'ffff, we make it impossible for a return check to erroneously pass
push(qword, 0xffffffff);
// Allocate 32 bytes of shadow stack on windows, and 8 more bytes to realign stack to 16 bytes after our 4-byte push
sub(rsp, isWindows() ? (8 + 32) : 8);
// Lower rsp by 8 for the PICA return stack to be consistent
sub(rsp, 8);
// Tail call to shader code entrypoint
jmp(arg2);
@ -104,7 +101,7 @@ void ShaderEmitter::compileInstruction(const PICAShader& shaderUnit) {
// See if PC is a possible return PC and emit the proper code if so
if (std::binary_search(returnPCs.begin(), returnPCs.end(), recompilerPC)) {
uintptr_t stackOffsetForPC = isWindows() ? (8 + 32) : 8;
constexpr uintptr_t stackOffsetForPC = 8;
Label end;
// Check if return address == recompilerPC, ie if we should return
@ -376,11 +373,8 @@ void ShaderEmitter::checkBoolUniform(const PICAShader& shader, u32 instruction)
void ShaderEmitter::recEND(const PICAShader& shader, u32 instruction) {
// Undo anything the prologue did and return
// Dellocate shadow stack on Windows, and deallocate the stack space taken up for the return guard
add(rsp, isWindows() ? (16 + 32) : 16);
// Restore registers
pop(statePointer);
// Deallocate the 8 bytes taken up for the return guard + the 8 bytes of rsp padding we inserted in the prologue
add(rsp, 16);
ret();
}
@ -718,16 +712,11 @@ void ShaderEmitter::recCALL(const PICAShader& shader, u32 instruction) {
// Push return PC as stack parameter. This is a decently fast solution and Citra does the same but we should probably switch to a proper PICA-like
// Callstack, because it's not great to have an infinitely expanding call stack where popping from empty stack is undefined as hell
push(qword, dest + num);
if constexpr (isWindows()) {
// Allocate 32 bytes of shadow space on windows
sub(rsp, 32);
}
// Call subroutine, Xbyak will update the label if it hasn't been initialized yet
call(instructionLabels[dest]);
// Fix up stack after returning. The 8 from before becomes a 16 because we're also skipping the qword we pushed
add(rsp, isWindows() ? (8 + 32) : 8);
// Fix up stack after returning by adding 8 to rsp and "popping" the return PC
add(rsp, 8);
}
void ShaderEmitter::recCALLC(const PICAShader& shader, u32 instruction) {