[LLVM-C] Add Bindings For Named Metadata

Summary: Add a new type for named metadata nodes.  Use this to implement iterators and accessors for NamedMDNodes and extend the echo test to use them to copy module-level debug information.

Reviewers: whitequark, deadalnix, aprantl, dexonsmith

Reviewed By: whitequark

Subscribers: Wallbraker, JDevlieghere, llvm-commits, harlanhaskins

Differential Revision: https://reviews.llvm.org/D47179

llvm-svn: 341085

llvm/include/llvm-c/Core.h

@@ -842,6 +842,63 @@ LLVMContextRef LLVMGetModuleContext(LLVMModuleRef M);
  */
 LLVMTypeRef LLVMGetTypeByName(LLVMModuleRef M, const char *Name);
 
+/**
+ * Obtain an iterator to the first NamedMDNode in a Module.
+ *
+ * @see llvm::Module::named_metadata_begin()
+ */
+LLVMNamedMDNodeRef LLVMGetFirstNamedMetadata(LLVMModuleRef M);
+
+/**
+ * Obtain an iterator to the last NamedMDNode in a Module.
+ *
+ * @see llvm::Module::named_metadata_end()
+ */
+LLVMNamedMDNodeRef LLVMGetLastNamedMetadata(LLVMModuleRef M);
+
+/**
+ * Advance a NamedMDNode iterator to the next NamedMDNode.
+ *
+ * Returns NULL if the iterator was already at the end and there are no more
+ * named metadata nodes.
+ */
+LLVMNamedMDNodeRef LLVMGetNextNamedMetadata(LLVMNamedMDNodeRef NamedMDNode);
+
+/**
+ * Decrement a NamedMDNode iterator to the previous NamedMDNode.
+ *
+ * Returns NULL if the iterator was already at the beginning and there are
+ * no previous named metadata nodes.
+ */
+LLVMNamedMDNodeRef LLVMGetPreviousNamedMetadata(LLVMNamedMDNodeRef NamedMDNode);
+
+/**
+ * Retrieve a NamedMDNode with the given name, returning NULL if no such
+ * node exists.
+ *
+ * @see llvm::Module::getNamedMetadata()
+ */
+LLVMNamedMDNodeRef LLVMGetNamedMetadata(LLVMModuleRef M,
+                                        const char *Name, size_t NameLen);
+
+/**
+ * Retrieve a NamedMDNode with the given name, creating a new node if no such
+ * node exists.
+ *
+ * @see llvm::Module::getOrInsertNamedMetadata()
+ */
+LLVMNamedMDNodeRef LLVMGetOrInsertNamedMetadata(LLVMModuleRef M,
+                                                const char *Name,
+                                                size_t NameLen);
+
+/**
+ * Retrieve the name of a NamedMDNode.
+ *
+ * @see llvm::NamedMDNode::getName()
+ */
+const char *LLVMGetNamedMetadataName(LLVMNamedMDNodeRef NamedMD,
+                                     size_t *NameLen);
+
 /**
  * Obtain the number of operands for named metadata in a module.
  *

llvm/include/llvm-c/Types.h

@@ -89,6 +89,13 @@ typedef struct LLVMOpaqueBasicBlock *LLVMBasicBlockRef;
  */
 typedef struct LLVMOpaqueMetadata *LLVMMetadataRef;
 
+/**
+ * Represents an LLVM Named Metadata Node.
+ *
+ * This models llvm::NamedMDNode.
+ */
+typedef struct LLVMOpaqueNamedMDNode *LLVMNamedMDNodeRef;
+
 /**
  * Represents an LLVM basic block builder.
  *

llvm/include/llvm/IR/Metadata.h

@@ -1316,10 +1316,11 @@ public:
 //===----------------------------------------------------------------------===//
 /// A tuple of MDNodes.
 ///
-/// Despite its name, a NamedMDNode isn't itself an MDNode. NamedMDNodes belong
-/// to modules, have names, and contain lists of MDNodes.
+/// Despite its name, a NamedMDNode isn't itself an MDNode.
 ///
-/// TODO: Inherit from Metadata.
+/// NamedMDNodes are named module-level entities that contain lists of MDNodes.
+///
+/// It is illegal for a NamedMDNode to appear as an operand of an MDNode.
 class NamedMDNode : public ilist_node<NamedMDNode> {
   friend class LLVMContextImpl;
   friend class Module;
@@ -1420,6 +1421,9 @@ public:
   }
 };
 
+// Create wrappers for C Binding types (see CBindingWrapping.h).
+DEFINE_ISA_CONVERSION_FUNCTIONS(NamedMDNode, LLVMNamedMDNodeRef)
+
 } // end namespace llvm
 
 #endif // LLVM_IR_METADATA_H

llvm/lib/IR/Core.cpp

@@ -1065,6 +1065,54 @@ unsigned LLVMGetMDNodeNumOperands(LLVMValueRef V) {
   return cast<MDNode>(MD->getMetadata())->getNumOperands();
 }
 
+LLVMNamedMDNodeRef LLVMGetFirstNamedMetadata(LLVMModuleRef M) {
+  Module *Mod = unwrap(M);
+  Module::named_metadata_iterator I = Mod->named_metadata_begin();
+  if (I == Mod->named_metadata_end())
+    return nullptr;
+  return wrap(&*I);
+}
+
+LLVMNamedMDNodeRef LLVMGetLastNamedMetadata(LLVMModuleRef M) {
+  Module *Mod = unwrap(M);
+  Module::named_metadata_iterator I = Mod->named_metadata_end();
+  if (I == Mod->named_metadata_begin())
+    return nullptr;
+  return wrap(&*--I);
+}
+
+LLVMNamedMDNodeRef LLVMGetNextNamedMetadata(LLVMNamedMDNodeRef NMD) {
+  NamedMDNode *NamedNode = unwrap<NamedMDNode>(NMD);
+  Module::named_metadata_iterator I(NamedNode);
+  if (++I == NamedNode->getParent()->named_metadata_end())
+    return nullptr;
+  return wrap(&*I);
+}
+
+LLVMNamedMDNodeRef LLVMGetPreviousNamedMetadata(LLVMNamedMDNodeRef NMD) {
+  NamedMDNode *NamedNode = unwrap<NamedMDNode>(NMD);
+  Module::named_metadata_iterator I(NamedNode);
+  if (I == NamedNode->getParent()->named_metadata_begin())
+    return nullptr;
+  return wrap(&*--I);
+}
+
+LLVMNamedMDNodeRef LLVMGetNamedMetadata(LLVMModuleRef M,
+                                        const char *Name, size_t NameLen) {
+  return wrap(unwrap(M)->getNamedMetadata(StringRef(Name, NameLen)));
+}
+
+LLVMNamedMDNodeRef LLVMGetOrInsertNamedMetadata(LLVMModuleRef M,
+                                                const char *Name, size_t NameLen) {
+  return wrap(unwrap(M)->getOrInsertNamedMetadata({Name, NameLen}));
+}
+
+const char *LLVMGetNamedMetadataName(LLVMNamedMDNodeRef NMD, size_t *NameLen) {
+  NamedMDNode *NamedNode = unwrap<NamedMDNode>(NMD);
+  *NameLen = NamedNode->getName().size();
+  return NamedNode->getName().data();
+}
+
 void LLVMGetMDNodeOperands(LLVMValueRef V, LLVMValueRef *Dest) {
   auto *MD = cast<MetadataAsValue>(unwrap(V));
   if (auto *MDV = dyn_cast<ValueAsMetadata>(MD->getMetadata())) {

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

@@ -166,6 +166,11 @@ exit:
   ret void
 }
 
-!llvm.module.flags = !{!1}
+!llvm.module.flags = !{!0}
+!named = !{!1, !2, !3}
 
-!1 = !{i32 2, !"Debug Info Version", i32 3}
+!0 = !{i32 2, !"Debug Info Version", i32 3}
+!1 = distinct !{}
+!2 = distinct !{}
+!3 = !{!4}
+!4 = distinct !{}

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

@@ -916,7 +916,7 @@ AliasDecl:
   if (!Begin) {
     if (End != nullptr)
       report_fatal_error("Range has an end but no beginning");
-    return;
+    goto NamedMDDecl;
   }
 
   Cur = Begin;
@@ -943,6 +943,38 @@ AliasDecl:
 
     Cur = Next;
   }
+
+NamedMDDecl:
+  LLVMNamedMDNodeRef BeginMD = LLVMGetFirstNamedMetadata(Src);
+  LLVMNamedMDNodeRef EndMD = LLVMGetLastNamedMetadata(Src);
+  if (!BeginMD) {
+    if (EndMD != nullptr)
+      report_fatal_error("Range has an end but no beginning");
+    return;
+  }
+
+  LLVMNamedMDNodeRef CurMD = BeginMD;
+  LLVMNamedMDNodeRef NextMD = nullptr;
+  while (true) {
+    size_t NameLen;
+    const char *Name = LLVMGetNamedMetadataName(CurMD, &NameLen);
+    if (LLVMGetNamedMetadata(M, Name, NameLen))
+      report_fatal_error("Named Metadata Node already cloned");
+    LLVMGetOrInsertNamedMetadata(M, Name, NameLen);
+
+    NextMD = LLVMGetNextNamedMetadata(CurMD);
+    if (NextMD == nullptr) {
+      if (CurMD != EndMD)
+        report_fatal_error("");
+      break;
+    }
+
+    LLVMNamedMDNodeRef PrevMD = LLVMGetPreviousNamedMetadata(NextMD);
+    if (PrevMD != CurMD)
+      report_fatal_error("Next.Previous global is not Current");
+
+    CurMD = NextMD;
+  }
 }
 
 static void clone_symbols(LLVMModuleRef Src, LLVMModuleRef M) {
@@ -1041,7 +1073,7 @@ AliasClone:
   if (!Begin) {
     if (End != nullptr)
       report_fatal_error("Range has an end but no beginning");
-    return;
+    goto NamedMDClone;
   }
 
   Cur = Begin;
@@ -1073,6 +1105,47 @@ AliasClone:
 
     Cur = Next;
   }
+
+NamedMDClone:
+  LLVMNamedMDNodeRef BeginMD = LLVMGetFirstNamedMetadata(Src);
+  LLVMNamedMDNodeRef EndMD = LLVMGetLastNamedMetadata(Src);
+  if (!BeginMD) {
+    if (EndMD != nullptr)
+      report_fatal_error("Range has an end but no beginning");
+    return;
+  }
+
+  LLVMNamedMDNodeRef CurMD = BeginMD;
+  LLVMNamedMDNodeRef NextMD = nullptr;
+  while (true) {
+    size_t NameLen;
+    const char *Name = LLVMGetNamedMetadataName(CurMD, &NameLen);
+    LLVMNamedMDNodeRef NamedMD = LLVMGetNamedMetadata(M, Name, NameLen);
+    if (!NamedMD)
+      report_fatal_error("Named MD Node must have been declared already");
+
+    unsigned OperandCount = LLVMGetNamedMetadataNumOperands(Src, Name);
+    LLVMValueRef *OperandBuf = static_cast<LLVMValueRef *>(
+              safe_malloc(OperandCount * sizeof(LLVMValueRef)));
+    LLVMGetNamedMetadataOperands(Src, Name, OperandBuf);
+    for (unsigned i = 0, e = OperandCount; i != e; ++i) {
+      LLVMAddNamedMetadataOperand(M, Name, OperandBuf[i]);
+    }
+    free(OperandBuf);
+
+    NextMD = LLVMGetNextNamedMetadata(CurMD);
+    if (NextMD == nullptr) {
+      if (CurMD != EndMD)
+        report_fatal_error("Last Named MD Node does not match End");
+      break;
+    }
+
+    LLVMNamedMDNodeRef PrevMD = LLVMGetPreviousNamedMetadata(NextMD);
+    if (PrevMD != CurMD)
+      report_fatal_error("Next.Previous Named MD Node is not Current");
+
+    CurMD = NextMD;
+  }
 }
 
 int llvm_echo(void) {
@@ -1089,18 +1162,6 @@ int llvm_echo(void) {
   LLVMSetSourceFileName(M, SourceFileName, SourceFileLen);
   LLVMSetModuleIdentifier(M, ModuleName, ModuleIdentLen);
 
-  size_t SourceFlagsLen;
-  LLVMModuleFlagEntry *ModuleFlags =
-      LLVMCopyModuleFlagsMetadata(Src, &SourceFlagsLen);
-  for (unsigned i = 0; i < SourceFlagsLen; ++i) {
-    size_t EntryNameLen;
-    const char *EntryName =
-        LLVMModuleFlagEntriesGetKey(ModuleFlags, i, &EntryNameLen);
-    LLVMAddModuleFlag(M, LLVMModuleFlagEntriesGetFlagBehavior(ModuleFlags, i),
-                      EntryName, EntryNameLen,
-                      LLVMModuleFlagEntriesGetMetadata(ModuleFlags, i));
-  }
-
   LLVMSetTarget(M, LLVMGetTarget(Src));
   LLVMSetModuleDataLayout(M, LLVMGetModuleDataLayout(Src));
   if (strcmp(LLVMGetDataLayoutStr(M), LLVMGetDataLayoutStr(Src)))
@@ -1115,7 +1176,6 @@ int llvm_echo(void) {
   char *Str = LLVMPrintModuleToString(M);
   fputs(Str, stdout);
 
-  LLVMDisposeModuleFlagsMetadata(ModuleFlags);
   LLVMDisposeMessage(Str);
   LLVMDisposeModule(Src);
   LLVMDisposeModule(M);