================
@@ -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++) {
+
+ if (Options[Index].Conditions.Features[0].starts_with("default")) {
+ HasDefault = true;
+ DefaultIndex = Index;
+ continue;
+ }
+
+ Builder.SetInsertPoint(CurBlock);
+
+ std::vector<std::string> TargetAttrFeats =
+ getContext()
+ .getTargetInfo()
+ .parseTargetAttr(Options[Index].Conditions.Features[0])
+ .Features;
+
+ if (TargetAttrFeats.empty())
+ continue;
+
+ // Two conditions need to be checked for the current version:
+ //
+ // 1. LengthCondition: The maximum group ID of the required extension
+ // does not exceed the runtime object's length.
+ // __riscv_feature_bits.length > MAX_USED_GROUPID
+ //
+ // 2. FeaturesCondition: The bitmask of the required extension has been
+ // enabled by the runtime object.
+ // (__riscv_feature_bits.features[i] & REQUIRED_BITMASK) ==
+ // REQUIRED_BITMASK
+ //
+ // When both conditions are met, return this version of the function.
+ // Otherwise, try the next version.
+ //
+ // if (LengthConditionVersion1 && FeaturesConditionVersion1)
+ // return Version1;
+ // else if (LengthConditionVersion2 && FeaturesConditionVersion2)
+ // return Version2;
+ // else if (LengthConditionVersion3 && FeaturesConditionVersion3)
+ // return Version3;
+ // ...
+ // else
+ // return DefaultVersion;
+ llvm::SmallVector<StringRef, 8> CurrTargetAttrFeats;
+
+ for (auto Feat : TargetAttrFeats)
+ CurrTargetAttrFeats.push_back(StringRef(Feat).substr(1));
----------------
BeMg wrote:
Current target_clones syntax only accept the individual extension, so
`parseTargetAttr` always return extension with `+` sign.
But it worth to check here again to avoid the very surprising semantics.
https://github.com/llvm/llvm-project/pull/85786
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