[NFC][Docs] Add missing Doxygen group comments for LLVM-C

The LLVM-C API is relatively small so we've previously added doxygen tags
so it's easier to navigate the LLVM-C web docs. Over the years, more
headers were added without proper doxygen tags, effectively hiding them
from the main LLVM-C doxygen page. This patch adds comments to headers
which did not have them.

Reviewed By: lhames

Differential Revision: https://reviews.llvm.org/D112474

llvm/include/llvm-c/Comdat.h

@@ -19,6 +19,13 @@
 
 LLVM_C_EXTERN_C_BEGIN
 
+/**
+ * @defgroup LLVMCCoreComdat Comdats
+ * @ingroup LLVMCCore
+ *
+ * @{
+ */
+
 typedef enum {
   LLVMAnyComdatSelectionKind,        ///< The linker may choose any COMDAT.
   LLVMExactMatchComdatSelectionKind, ///< The data referenced by the COMDAT must
@@ -66,6 +73,10 @@ LLVMComdatSelectionKind LLVMGetComdatSelectionKind(LLVMComdatRef C);
  */
 void LLVMSetComdatSelectionKind(LLVMComdatRef C, LLVMComdatSelectionKind Kind);
 
+/**
+ * @}
+ */
+
 LLVM_C_EXTERN_C_END
 
 #endif

llvm/include/llvm-c/Core.h

@@ -4091,6 +4091,7 @@ void LLVMDisposeMemoryBuffer(LLVMMemoryBufferRef MemBuf);
 
 /**
  * @defgroup LLVMCCorePassRegistry Pass Registry
+ * @ingroup LLVMCCore
  *
  * @{
  */
@@ -4105,6 +4106,7 @@ LLVMPassRegistryRef LLVMGetGlobalPassRegistry(void);
 
 /**
  * @defgroup LLVMCCorePassManagers Pass Managers
+ * @ingroup LLVMCCore
  *
  * @{
  */

llvm/include/llvm-c/DebugInfo.h

@@ -21,6 +21,13 @@
 
 LLVM_C_EXTERN_C_BEGIN
 
+/**
+ * @defgroup LLVMCCoreDebugInfo Debug Information
+ * @ingroup LLVMCCore
+ *
+ * @{
+ */
+
 /**
  * Debug info flags.
  */
@@ -1367,6 +1374,10 @@ void LLVMInstructionSetDebugLoc(LLVMValueRef Inst, LLVMMetadataRef Loc);
  */
 LLVMMetadataKind LLVMGetMetadataKind(LLVMMetadataRef Metadata);
 
+/**
+ * @}
+ */
+
 LLVM_C_EXTERN_C_END
 
 #endif

llvm/include/llvm-c/DisassemblerTypes.h

@@ -17,6 +17,12 @@
 #include <stddef.h>
 #endif
 
+/**
+ * @addtogroup LLVMCDisassembler
+ *
+ * @{
+ */
+
 /**
  * An opaque reference to a disassembler context.
  */
@@ -157,4 +163,8 @@ typedef const char *(*LLVMSymbolLookupCallback)(void *DisInfo,
 /* The output reference is to a C++ symbol name. */
 #define LLVMDisassembler_ReferenceType_DeMangled_Name 9
 
+/**
+ * @}
+ */
+
 #endif

llvm/include/llvm-c/Error.h

@@ -18,6 +18,13 @@
 
 LLVM_C_EXTERN_C_BEGIN
 
+/**
+ * @defgroup LLVMCError Error Handling
+ * @ingroup LLVMC
+ *
+ * @{
+ */
+
 #define LLVMErrorSuccess 0
 
 /**
@@ -67,6 +74,10 @@ LLVMErrorTypeId LLVMGetStringErrorTypeId(void);
  */
 LLVMErrorRef LLVMCreateStringError(const char *ErrMsg);
 
+/**
+ * @}
+ */
+
 LLVM_C_EXTERN_C_END
 
 #endif

llvm/include/llvm-c/ErrorHandling.h

@@ -18,6 +18,12 @@
 
 LLVM_C_EXTERN_C_BEGIN
 
+/**
+ * @addtogroup LLVMCError
+ *
+ * @{
+ */
+
 typedef void (*LLVMFatalErrorHandler)(const char *Reason);
 
 /**
@@ -42,6 +48,10 @@ void LLVMResetFatalErrorHandler(void);
  */
 void LLVMEnablePrettyStackTrace(void);
 
+/**
+ * @}
+ */
+
 LLVM_C_EXTERN_C_END
 
 #endif

llvm/include/llvm-c/IRReader.h

@@ -19,6 +19,13 @@
 
 LLVM_C_EXTERN_C_BEGIN
 
+/**
+ * @defgroup LLVMCCoreIRReader IR Reader
+ * @ingroup LLVMCCore
+ *
+ * @{
+ */
+
 /**
  * Read LLVM IR from a memory buffer and convert it into an in-memory Module
  * object. Returns 0 on success.
@@ -32,6 +39,10 @@ LLVMBool LLVMParseIRInContext(LLVMContextRef ContextRef,
                               LLVMMemoryBufferRef MemBuf, LLVMModuleRef *OutM,
                               char **OutMessage);
 
+/**
+ * @}
+ */
+
 LLVM_C_EXTERN_C_END
 
 #endif

llvm/include/llvm-c/LLJIT.h

@@ -31,6 +31,13 @@
 
 LLVM_C_EXTERN_C_BEGIN
 
+/**
+ * @defgroup LLVMCExecutionEngineLLJIT LLJIT
+ * @ingroup LLVMCExecutionEngine
+ *
+ * @{
+ */
+
 /**
  * A function for constructing an ObjectLinkingLayer instance to be used
  * by an LLJIT instance.
@@ -235,6 +242,10 @@ LLVMOrcIRTransformLayerRef LLVMOrcLLJITGetIRTransformLayer(LLVMOrcLLJITRef J);
  */
 const char *LLVMOrcLLJITGetDataLayoutStr(LLVMOrcLLJITRef J);
 
+/**
+ * @}
+ */
+
 LLVM_C_EXTERN_C_END
 
 #endif /* LLVM_C_LLJIT_H */

llvm/include/llvm-c/Linker.h

@@ -19,6 +19,13 @@
 
 LLVM_C_EXTERN_C_BEGIN
 
+/**
+ * @defgroup LLVMCCoreLinker Linker
+ * @ingroup LLVMCCore
+ *
+ * @{
+ */
+
 /* This enum is provided for backwards-compatibility only. It has no effect. */
 typedef enum {
   LLVMLinkerDestroySource = 0, /* This is the default behavior. */
@@ -35,4 +42,8 @@ LLVMBool LLVMLinkModules2(LLVMModuleRef Dest, LLVMModuleRef Src);
 
 LLVM_C_EXTERN_C_END
 
+/**
+ * @}
+ */
+
 #endif

llvm/include/llvm-c/Orc.h

@@ -33,6 +33,13 @@
 
 LLVM_C_EXTERN_C_BEGIN
 
+/**
+ * @defgroup LLVMCExecutionEngineORC On-Request-Compilation
+ * @ingroup LLVMCExecutionEngine
+ *
+ * @{
+ */
+
 /**
  * Represents an address in the executor process.
  */
@@ -1176,6 +1183,10 @@ void LLVMOrcDisposeDumpObjects(LLVMOrcDumpObjectsRef DumpObjects);
 LLVMErrorRef LLVMOrcDumpObjects_CallOperator(LLVMOrcDumpObjectsRef DumpObjects,
                                              LLVMMemoryBufferRef *ObjBuffer);
 
+/**
+ * @}
+ */
+
 LLVM_C_EXTERN_C_END
 
 #endif /* LLVM_C_ORC_H */

llvm/include/llvm-c/OrcEE.h

@@ -32,6 +32,13 @@
 
 LLVM_C_EXTERN_C_BEGIN
 
+/**
+ * @defgroup LLVMCExecutionEngineORCEE ExecutionEngine-based ORC Utils
+ * @ingroup LLVMCExecutionEngine
+ *
+ * @{
+ */
+
 /**
  * Create a RTDyldObjectLinkingLayer instance using the standard
  * SectionMemoryManager for memory management.
@@ -50,6 +57,10 @@ void LLVMOrcRTDyldObjectLinkingLayerRegisterJITEventListener(
     LLVMOrcObjectLayerRef RTDyldObjLinkingLayer,
     LLVMJITEventListenerRef Listener);
 
+/**
+ * @}
+ */
+
 LLVM_C_EXTERN_C_END
 
 #endif /* LLVM_C_ORCEE_H */

llvm/include/llvm-c/Support.h

@@ -20,6 +20,12 @@
 
 LLVM_C_EXTERN_C_BEGIN
 
+/**
+ * @addtogroup LLVMCCore
+ *
+ * @{
+ */
+
 /**
  * This function permanently loads the dynamic library at the given path.
  * It is safe to call this function multiple times for the same library.
@@ -57,6 +63,10 @@ void *LLVMSearchForAddressOfSymbol(const char *symbolName);
  */
 void LLVMAddSymbol(const char *symbolName, void *symbolValue);
 
+/**
+ * @}
+ */
+
 LLVM_C_EXTERN_C_END
 
 #endif

llvm/include/llvm-c/TargetMachine.h

@@ -25,6 +25,12 @@
 
 LLVM_C_EXTERN_C_BEGIN
 
+/**
+ * @addtogroup LLVMCTarget
+ *
+ * @{
+ */
+
 typedef struct LLVMOpaqueTargetMachine *LLVMTargetMachineRef;
 typedef struct LLVMTarget *LLVMTargetRef;
 
@@ -156,6 +162,10 @@ char* LLVMGetHostCPUFeatures(void);
 /** Adds the target-specific analysis passes to the pass manager. */
 void LLVMAddAnalysisPasses(LLVMTargetMachineRef T, LLVMPassManagerRef PM);
 
+/**
+ * @}
+ */
+
 LLVM_C_EXTERN_C_END
 
 #endif

llvm/include/llvm-c/Transforms/PassBuilder.h

@@ -18,6 +18,13 @@
 #include "llvm-c/TargetMachine.h"
 #include "llvm-c/Types.h"
 
+/**
+ * @defgroup LLVMCCoreNewPM New Pass Manager
+ * @ingroup LLVMCCore
+ *
+ * @{
+ */
+
 LLVM_C_EXTERN_C_BEGIN
 
 /**
@@ -97,6 +104,10 @@ void LLVMPassBuilderOptionsSetMergeFunctions(LLVMPassBuilderOptionsRef Options,
  */
 void LLVMDisposePassBuilderOptions(LLVMPassBuilderOptionsRef Options);
 
+/**
+ * @}
+ */
+
 LLVM_C_EXTERN_C_END
 
 #endif // LLVM_C_TRANSFORMS_PASSBUILDER_H