[RISCV][FMV] Support target_version (#99040)

This patch enable `target_version` attribute for RISC-V target.

The proposal of `target_version` syntax can be found at the
https://github.com/riscv-non-isa/riscv-c-api-doc/pull/48 (which has
landed), as modified by the proposed
https://github.com/riscv-non-isa/riscv-c-api-doc/pull/85 (which adds the
priority syntax).

`target_version` attribute will trigger the function multi-versioning
feature and act like `target_clones` attribute. See
https://github.com/llvm/llvm-project/pull/85786 for the implementation
of `target_clones`.

1 files changed, 6 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 25c1c49..5ba0981 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -4287,8 +4287,13 @@ void CodeGenModule::emitMultiVersionFunctions() {
           } else if (const auto *TVA = CurFD->getAttr<TargetVersionAttr>()) {
             if (TVA->isDefaultVersion() && IsDefined)
               ShouldEmitResolver = true;
-            TVA->getFeatures(Feats);
             llvm::Function *Func = createFunction(CurFD);
+            if (getTarget().getTriple().isRISCV()) {
+              Feats.push_back(TVA->getName());
+            } else {
+              assert(getTarget().getTriple().isAArch64());
+              TVA->getFeatures(Feats);
+            }
             Options.emplace_back(Func, /*Architecture*/ "", Feats);
           } else if (const auto *TC = CurFD->getAttr<TargetClonesAttr>()) {
             if (IsDefined)