[C API] Add getters for Target Extension Types to C API (llvm#96447)

Accessors for the name, type parameters, and integer parameters are
added. A test is added to echo.ll

This was originally done in
llvm#71291 but that has been stale
for several months. This re-applies the changes, but with some tweaks.
e.g. removing the bulk getters in favour of a simple get-by-index
approach for the type/integer parameters. The latter is more in line
with the rest of the API

llvm/docs/ReleaseNotes.rst

@@ -282,6 +282,12 @@ They are described in detail in the `debug info migration guide <https://llvm.or
   * ``LLVMDIBuilderInsertDbgValueBefore``
   * ``LLVMDIBuilderInsertDbgValueAtEnd``
 
+* Added the following functions for accessing a Target Extension Type's data:
+
+  * ``LLVMGetTargetExtTypeName``
+  * ``LLVMGetTargetExtTypeNumTypeParams``/``LLVMGetTargetExtTypeTypeParam``
+  * ``LLVMGetTargetExtTypeNumIntParams``/``LLVMGetTargetExtTypeIntParam``
+
 Changes to the CodeGen infrastructure
 -------------------------------------
 

llvm/include/llvm-c/Core.h

@@ -1710,6 +1710,42 @@ LLVMTypeRef LLVMTargetExtTypeInContext(LLVMContextRef C, const char *Name,
                                        unsigned *IntParams,
                                        unsigned IntParamCount);
 
+/**
+ * Obtain the name for this target extension type.
+ *
+ * @see llvm::TargetExtType::getName()
+ */
+const char *LLVMGetTargetExtTypeName(LLVMTypeRef TargetExtTy);
+
+/**
+ * Obtain the number of type parameters for this target extension type.
+ *
+ * @see llvm::TargetExtType::getNumTypeParameters()
+ */
+unsigned LLVMGetTargetExtTypeNumTypeParams(LLVMTypeRef TargetExtTy);
+
+/**
+ * Get the type parameter at the given index for the target extension type.
+ *
+ * @see llvm::TargetExtType::getTypeParameter()
+ */
+LLVMTypeRef LLVMGetTargetExtTypeTypeParam(LLVMTypeRef TargetExtTy,
+                                          unsigned Idx);
+
+/**
+ * Obtain the number of int parameters for this target extension type.
+ *
+ * @see llvm::TargetExtType::getNumIntParameters()
+ */
+unsigned LLVMGetTargetExtTypeNumIntParams(LLVMTypeRef TargetExtTy);
+
+/**
+ * Get the int parameter at the given index for the target extension type.
+ *
+ * @see llvm::TargetExtType::getIntParameter()
+ */
+unsigned LLVMGetTargetExtTypeIntParam(LLVMTypeRef TargetExtTy, unsigned Idx);
+
 /**
  * @}
  */

llvm/lib/IR/Core.cpp

@@ -954,6 +954,32 @@ LLVMTypeRef LLVMTargetExtTypeInContext(LLVMContextRef C, const char *Name,
       TargetExtType::get(*unwrap(C), Name, TypeParamArray, IntParamArray));
 }
 
+const char *LLVMGetTargetExtTypeName(LLVMTypeRef TargetExtTy) {
+  TargetExtType *Type = unwrap<TargetExtType>(TargetExtTy);
+  return Type->getName().data();
+}
+
+unsigned LLVMGetTargetExtTypeNumTypeParams(LLVMTypeRef TargetExtTy) {
+  TargetExtType *Type = unwrap<TargetExtType>(TargetExtTy);
+  return Type->getNumTypeParameters();
+}
+
+LLVMTypeRef LLVMGetTargetExtTypeTypeParam(LLVMTypeRef TargetExtTy,
+                                          unsigned Idx) {
+  TargetExtType *Type = unwrap<TargetExtType>(TargetExtTy);
+  return wrap(Type->getTypeParameter(Idx));
+}
+
+unsigned LLVMGetTargetExtTypeNumIntParams(LLVMTypeRef TargetExtTy) {
+  TargetExtType *Type = unwrap<TargetExtType>(TargetExtTy);
+  return Type->getNumIntParameters();
+}
+
+unsigned LLVMGetTargetExtTypeIntParam(LLVMTypeRef TargetExtTy, unsigned Idx) {
+  TargetExtType *Type = unwrap<TargetExtType>(TargetExtTy);
+  return Type->getIntParameter(Idx);
+}
+
 /*===-- Operations on values ----------------------------------------------===*/
 
 /*--.. Operations on all values ............................................--*/

llvm/test/Bindings/llvm-c/echo.ll

@@ -66,6 +66,23 @@ define void @types() {
   ret void
 }
 
+; Target extension types:
+define target("target.ext.1") @target_ext_01(target("target.ext.1") %0) {
+  ret target("target.ext.1") %0
+}
+
+define target("target.ext.2", i8, i1) @target_ext_02(target("target.ext.2", i8, i1) %0) {
+  ret target("target.ext.2", i8, i1) %0
+}
+
+define target("target.ext.3", 7) @target_ext_03(target("target.ext.3", 7) %0) {
+  ret target("target.ext.3", 7) %0
+}
+
+define target("target.ext.4", i1, i32, 7) @target_ext_04(target("target.ext.4", i1, i32, 7) %0) {
+  ret target("target.ext.4", i1, i32, 7) %0
+}
+
 define i32 @iops(i32 %a, i32 %b) {
   %1 = add i32 %a, %b
   %2 = mul i32 %a, %1

llvm/tools/llvm-c-test/echo.cpp

@@ -157,8 +157,26 @@ struct TypeCloner {
         return LLVMX86MMXTypeInContext(Ctx);
       case LLVMTokenTypeKind:
         return LLVMTokenTypeInContext(Ctx);
-      case LLVMTargetExtTypeKind:
-        assert(false && "Implement me");
+      case LLVMTargetExtTypeKind: {
+        const char *Name = LLVMGetTargetExtTypeName(Src);
+        unsigned NumTypeParams = LLVMGetTargetExtTypeNumTypeParams(Src);
+        unsigned NumIntParams = LLVMGetTargetExtTypeNumIntParams(Src);
+
+        SmallVector<LLVMTypeRef, 4> TypeParams((size_t)NumTypeParams);
+        SmallVector<unsigned, 4> IntParams((size_t)NumIntParams);
+
+        for (unsigned i = 0; i < TypeParams.size(); i++)
+          TypeParams[i] = Clone(LLVMGetTargetExtTypeTypeParam(Src, i));
+
+        for (unsigned i = 0; i < IntParams.size(); i++)
+          IntParams[i] = LLVMGetTargetExtTypeIntParam(Src, i);
+
+        LLVMTypeRef TargetExtTy = LLVMTargetExtTypeInContext(
+            Ctx, Name, TypeParams.data(), TypeParams.size(), IntParams.data(),
+            IntParams.size());
+
+        return TargetExtTy;
+      }
     }
 
     fprintf(stderr, "%d is not a supported typekind\n", Kind);