[clang] [llvm] [RISCV][FMV] Support target_clones (PR #85786)
Piyou Chen via cfe-commits
cfe-commits at lists.llvm.org
Sat Jul 20 06:05:02 PDT 2024
================
@@ -2854,10 +2854,121 @@ void CodeGenFunction::EmitMultiVersionResolver(
case llvm::Triple::aarch64:
EmitAArch64MultiVersionResolver(Resolver, Options);
return;
+ case llvm::Triple::riscv32:
+ case llvm::Triple::riscv64:
+ EmitRISCVMultiVersionResolver(Resolver, Options);
+ return;
default:
- assert(false && "Only implemented for x86 and AArch64 targets");
+ assert(false && "Only implemented for x86, AArch64 and RISC-V targets");
+ }
+}
+
+void CodeGenFunction::EmitRISCVMultiVersionResolver(
+ llvm::Function *Resolver, ArrayRef<MultiVersionResolverOption> Options) {
+
+ if (getContext().getTargetInfo().getTriple().getOS() !=
+ llvm::Triple::OSType::Linux) {
+ CGM.getDiags().Report(diag::err_os_unsupport_riscv_target_clones);
+ return;
+ }
+
+ llvm::BasicBlock *CurBlock = createBasicBlock("resolver_entry", Resolver);
+ Builder.SetInsertPoint(CurBlock);
+ EmitRISCVCpuInit();
+
+ bool SupportsIFunc = getContext().getTargetInfo().supportsIFunc();
+ bool HasDefault = false;
+ unsigned DefaultIndex = 0;
+ // Check the each candidate function.
+ for (unsigned Index = 0; Index < Options.size(); Index++) {
----------------
BeMg wrote:
For RISC-V target, I'm not sure that it is possible to define the score for all extension combination, then we could sort the order base on it. Or we could extend the `target_clones` syntax with `Priority=<NUM>` to indicate the order by user.
```
__attribute__((target_clones("default", "arch=+zba;Priority=1", "arch=+zba,+zbb;Priority=2"))) int bar() {
return 1;
}
```
And Yes, It will third version (+zba,+zbb) will be dead in current implementation. It will always get into +zba version or default.
https://github.com/llvm/llvm-project/pull/85786
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