rust-lang/rust
1
0
Fork 0
Code Issues Pull Requests Actions 2 Packages Projects Releases Wiki Activity

Rollup merge of #144232 - xacrimon:explicit-tail-call, r=WaffleLapkin

Browse Source 
Implement support for `become` and explicit tail call codegen for the LLVM backend

This PR implements codegen of explicit tail calls via `become` in `rustc_codegen_ssa` and support within the LLVM backend. Completes a task on (https://github.com/rust-lang/rust/issues/112788). This PR implements all the necessary bits to make explicit tail calls usable, other backends have received stubs for now and will ICE if you use `become` on them. I suspect there is some bikeshedding to be done on how we should go about implementing this for other backends, but it should be relatively straightforward for GCC after this is merged.

During development I also put together a POC bytecode VM based on tail call dispatch to test these changes out and analyze the codegen to make sure it generates expected assembly. That is available [here](https://github.com/xacrimon/tcvm).
This commit is contained in:
Stuart Cook
2025-07-31 15:42:00 +10:00
committed by GitHub
parent f478bec907 a448837045
commit 8628b78f24
10 changed files with 191 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
View File

@@ -1986,3 +1986,29 @@ extern "C" void LLVMRustSetNoSanitizeHWAddress(LLVMValueRef Global) {
MD.NoHWAddress = true;
GV.setSanitizerMetadata(MD);
}
enum class LLVMRustTailCallKind {
None = 0,
Tail = 1,
MustTail = 2,
NoTail = 3
};
extern "C" void LLVMRustSetTailCallKind(LLVMValueRef Call,
LLVMRustTailCallKind Kind) {
CallInst *CI = unwrap<CallInst>(Call);
switch (Kind) {
case LLVMRustTailCallKind::None:
CI->setTailCallKind(CallInst::TCK_None);
break;
case LLVMRustTailCallKind::Tail:
CI->setTailCallKind(CallInst::TCK_Tail);
break;
case LLVMRustTailCallKind::MustTail:
CI->setTailCallKind(CallInst::TCK_MustTail);
break;
case LLVMRustTailCallKind::NoTail:
CI->setTailCallKind(CallInst::TCK_NoTail);
break;
}
}