[IR] Add a target extension type to LLVM.

Target-extension types represent types that need to be preserved through
optimization, but otherwise are not introspectable by target-independent
optimizations. This patch doesn't add any uses of these types by an existing
backend, it only provides basic infrastructure such that these types would work
correctly.

Reviewed By: nikic, barannikov88

Differential Revision: https://reviews.llvm.org/D135202

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index cd66eeb..c39e3ea 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -941,6 +941,15 @@ static std::string getMangledTypeStr(Type *Ty, bool &HasUnnamedType) {
       Result += "nx";
     Result += "v" + utostr(EC.getKnownMinValue()) +
               getMangledTypeStr(VTy->getElementType(), HasUnnamedType);
+  } else if (TargetExtType *TETy = dyn_cast<TargetExtType>(Ty)) {
+    Result += "t";
+    Result += TETy->getName();
+    for (Type *ParamTy : TETy->type_params())
+      Result += "_" + getMangledTypeStr(ParamTy, HasUnnamedType);
+    for (unsigned IntParam : TETy->int_params())
+      Result += "_" + utostr(IntParam);
+    // Ensure nested target extension types are distinguishable.
+    Result += "t";
   } else if (Ty) {
     switch (Ty->getTypeID()) {
     default: llvm_unreachable("Unhandled type");