[VFABI] Read/Write functions for the VFABI attribute.

The attribute is stored at the `FunctionIndex` attribute set, with the
name "vector-function-abi-variant".

The get/set methods of the attribute have assertion to verify that:

1. Each name in the attribute is a valid VFABI mangled name.

2. Each name in the attribute correspond to a function declared in the
   module.

Differential Revision: https://reviews.llvm.org/D69976

1 files changed, 19 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/VectorUtils.cpp b/llvm/lib/Analysis/VectorUtils.cpp
index 600f57ab9d7..90e326687f7 100644
--- a/llvm/lib/Analysis/VectorUtils.cpp
+++ b/llvm/lib/Analysis/VectorUtils.cpp
@@ -1159,3 +1159,22 @@ void InterleaveGroup<Instruction>::addMetadata(Instruction *NewInst) const {
   propagateMetadata(NewInst, VL);
 }
 }
+
+void VFABI::getVectorVariantNames(
+    const CallInst &CI, SmallVectorImpl<std::string> &VariantMappings) {
+  const StringRef S =
+      CI.getAttribute(AttributeList::FunctionIndex, VFABI::MappingsAttrName)
+          .getValueAsString();
+  SmallVector<StringRef, 8> ListAttr;
+  S.split(ListAttr, ",");
+
+  for (auto &S : SetVector<StringRef>(ListAttr.begin(), ListAttr.end())) {
+#ifndef NDEBUG
+    Optional<VFInfo> Info = VFABI::tryDemangleForVFABI(S);
+    assert(Info.hasValue() && "Invalid name for a VFABI variant.");
+    assert(CI.getModule()->getFunction(Info.getValue().VectorName) &&
+           "Vector function is missing.");
+#endif
+    VariantMappings.push_back(S);
+  }
+}