[llvm] [LLVM-C] Support operand bundles (PR #73914)

[Nikita Popov via llvm-commits]

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@@ -3000,6 +3000,83 @@ LLVMValueRef LLVMMDNodeInContext(LLVMContextRef C, LLVMValueRef *Vals,
 /** Deprecated: Use LLVMMDNodeInContext2 instead. */
 LLVMValueRef LLVMMDNode(LLVMValueRef *Vals, unsigned Count);
 
+/**
+ * @}
+ */
+
+/**
+ * @defgroup LLVMCCoreOperandBundle Operand Bundles
+ *
+ * Functions in this group operate on LLVMOperandBundleRef instances that
+ * correspond to llvm::OperandBundleDef instances.
+ *
+ * @see llvm::OperandBundleDef
+ *
+ * @{
+ */
+
+/**
+ * Create a new operand bundle.
+ *
+ * Every invocation should be paired with LLVMDisposeOperandBundle() or memory
+ * will be leaked.
+ *
+ * @param Tag Tag name of the operand bundle
+ * @param TagLen Length of Tag
+ * @param Args Memory address of an array of bundle operands
+ * @param NumArgs Length of Args
+ */
+LLVMOperandBundleRef LLVMCreateOperandBundle(const char *Tag, unsigned TagLen,
+                                             LLVMValueRef *Args,
+                                             unsigned NumArgs);
+
+/**
+ * Destroy an operand bundle.
+ *
+ * This must be called for every created operand bundle or memory will be
+ * leaked.
+ */
+void LLVMDisposeOperandBundle(LLVMOperandBundleRef Bundle);
+
+/**
+ * Obtain the tag of an operand bundle as a string.
+ *
+ * @param Bundle Operand bundle to obtain tag of.
+ * @param Len Out parameter which holds the length of the returned string.
+ * @return The tag name of Bundle.
+ * @see OperandBundleDef::getTag()
+ */
+const char *LLVMGetOperandBundleTag(LLVMOperandBundleRef Bundle, size_t *Len);
+
+/**
+ * Obtain the number of operands for an operand bundle.
+ *
+ * @param Bundle Operand bundle to obtain operand count of.
+ * @return The number of operands.
+ * @see OperandBundleDef::input_size()
+ */
+unsigned LLVMGetNumOperandBundleArgs(LLVMOperandBundleRef Bundle);
+
+/**
+ * Obtain the operands for an operand bundle.
+ *
+ * @param Bundle Operand bundle to obtain operands of.
+ * @param Dest Memory address of an array to be filled with operands.
+ * @see OperandBundleDef::inputs()
+ */
+void LLVMGetOperandBundleArgs(LLVMOperandBundleRef Bundle, LLVMValueRef *Dest);
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nikic wrote:

I think it would be better to keep the variant with index rather the one without. I basically don't really see the point for an API that will allocate an extra buffer to store all elements into, when we can just as well query them one by one.

https://github.com/llvm/llvm-project/pull/73914