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

[Quinton Miller 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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HertzDevil wrote:

LLVM has all of these:

* `LLVMCountStructElementTypes`, `LLVMGetStructElementTypes`, `LLVMStructGetTypeAtIndex`
* `LLVMCountParams`, `LLVMGetParams`, `LLVMGetParam`

But it seems they are the minority and the index-less getter is usually the only one defined. I don't think the two APIs in this PR make a huge performance difference so I guess only the index-less one will suffice

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