fabi/Xenia-Canary
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Revert "place locals on backend pages"

Browse Source 
This reverts commit fe7dc26e3f.

Reason:
- It gives no real performance impact, but introduces issues
This commit is contained in:
Gliniak
2026-03-11 19:50:32 +01:00
parent b24ea8ef99
commit 10f66a47f6
3 changed files with 20 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
src/xenia/cpu/backend/x64/x64_emitter.cc
View File

@@ -208,36 +208,8 @@ bool X64Emitter::Emit(HIRBuilder* builder, EmitFunctionInfo& func_info) {
// IMPORTANT: any changes to the prolog must be kept in sync with
// X64CodeCache, which dynamically generates exception information.
// Adding or changing anything here must be matched!
/*
pick a page to use as the local base as close to the commonly accessed page
that contains most backend fields the sizes that are checked are chosen
based on PTE coalescing sizes. zen does 16k or 32k
*/
size_t stack_size = StackLayout::GUEST_STACK_SIZE;
if (stack_offset < (4096 - sizeof(X64BackendContext))) {
locals_page_delta_ = 4096;
} else if (stack_offset <
(16384 - sizeof(X64BackendContext))) { // 16k PTE coalescing
locals_page_delta_ = 16384;
} else if (stack_offset < (32768 - sizeof(X64BackendContext))) {
locals_page_delta_ = 32768;
} else if (stack_offset < (65536 - sizeof(X64BackendContext))) {
locals_page_delta_ = 65536;
} else {
// extremely unlikely, fall back to stack
stack_size =
xe::align<size_t>(StackLayout::GUEST_STACK_SIZE + stack_offset, 16);
locals_page_delta_ = 0;
}
// Ensure that after we SUB the stack_size, RSP is 16-byte aligned.
// On function entry, RSP is misaligned by 8 (due to CALL pushing return
// address). So we need stack_size to be 8 mod 16, not 0 mod 16.
if ((stack_size % 16) == 0) {
stack_size += 8; // Make it 8 mod 16
}
assert_true((stack_size % 16) == 8); // Should be 8 mod 16 for alignment
const size_t stack_size = StackLayout::GUEST_STACK_SIZE + stack_offset;
assert_true((stack_size + 8) % 16 == 0);
func_info.stack_size = stack_size;
stack_size_ = stack_size;
@@ -1630,9 +1602,7 @@ SimdDomain X64Emitter::DeduceSimdDomain(const hir::Value* for_value) {
return SimdDomain::DONTCARE;
}
Xbyak::RegExp X64Emitter::GetLocalsBase() const {
return !locals_page_delta_ ? rsp : GetContextReg() - locals_page_delta_;
}
Xbyak::Address X64Emitter::GetBackendCtxPtr(int offset_in_x64backendctx) const {
/*
index context ptr negatively to get to backend ctx field