[LLVM-C] Use Length-Providing Value Name Getters and Setters

[CodaFi]

Summary

• Provide LLVMGetValueName2 and LLVMSetValueName2 that return and take the length of the provided C string respectively
• Deprecate LLVMGetValueName and LLVMSetValueName

[whitequark]

First, the naming here is absurdly confusing. Second, it's also inconsistent with all other functions, e.g. LLVMGetSourceFileName/LLVMSetSourceFileName.

Use LLVMGetValueName2 and LLVMSetValueName2, since this is what we do when updating function signatures in the C API.

[CodaFi]

In D46890#1102616, @whitequark wrote:

First, the naming here is absurdly confusing. Second, it's also inconsistent with all other functions, e.g. LLVMGetSourceFileName/LLVMSetSourceFileName.

Use LLVMGetValueName2 and LLVMSetValueName2, since this is what we do when updating function signatures in the C API.

No problem. I'll update the names.

[whitequark]

Thanks!

include/llvm-c/Core.h

  */
 LLVMValueKind LLVMGetValueKind(LLVMValueRef Val);
 
 /**
  * Obtain the string name of a value.
  *
  * @see llvm::Value::getName()
  */
-const char *LLVMGetValueName(LLVMValueRef Val);
+const char *LLVMValueGetName(LLVMValueRef Val, size_t *Length);
 
 /**
  * Set the string name of a value.
  *
  * @see llvm::Value::setName()
  */
-void LLVMSetValueName(LLVMValueRef Val, const char *Name);
+void LLVMValueSetName(LLVMValueRef Val, const char *Name, size_t NameLen);
 
 /**
  * Dump a representation of a value to stderr.
  *
  * @see llvm::Value::dump()
  */
 void LLVMDumpValue(LLVMValueRef Val);
 

  */
 #define LLVM_DECLARE_VALUE_CAST(name) \
   LLVMValueRef LLVMIsA##name(LLVMValueRef Val);
 LLVM_FOR_EACH_VALUE_SUBCLASS(LLVM_DECLARE_VALUE_CAST)
 
 LLVMValueRef LLVMIsAMDNode(LLVMValueRef Val);
 LLVMValueRef LLVMIsAMDString(LLVMValueRef Val);
 
+/** Deprecated: Use LLVMValueGetName instead. */
+const char *LLVMGetValueName(LLVMValueRef Val);
+/** Deprecated: Use LLVMValueSetName instead. */
+void LLVMSetValueName(LLVMValueRef Val, const char *Name);
+
 /**
  * @}
  */
 
 /**
  * @defgroup LLVMCCoreValueUses Usage
  *
  * This module defines functions that allow you to inspect the uses of a

lib/IR/Core.cpp

#define HANDLE_VALUE(Name) \
   case Value::Name##Val: \
     return LLVM##Name##ValueKind;
 #include "llvm/IR/Value.def"
   default:
     return LLVMInstructionValueKind;
   }
 }
 
+const char *LLVMValueGetName(LLVMValueRef Val, size_t *Length) {
+  auto *V = unwrap(Val);
+  *Length = V->getName().size();
+  return V->getName().data();
+}
+
+void LLVMValueSetName(LLVMValueRef Val, const char *Name, size_t NameLen) {
+  unwrap(Val)->setName(StringRef(Name, NameLen));
+}
+
 const char *LLVMGetValueName(LLVMValueRef Val) {
   return unwrap(Val)->getName().data();
 }
 
 void LLVMSetValueName(LLVMValueRef Val, const char *Name) {
   unwrap(Val)->setName(Name);
 }
 

tools/llvm-c-test/echo.cpp

static ValueMap clone_params(LLVMValueRef Src, LLVMValueRef Dst) {
   LLVMValueRef SrcLast = LLVMGetLastParam(Src);
   LLVMValueRef DstLast = LLVMGetLastParam(Dst);
 
   LLVMValueRef SrcCur = SrcFirst;
   LLVMValueRef DstCur = DstFirst;
   LLVMValueRef SrcNext = nullptr;
   LLVMValueRef DstNext = nullptr;
   while (true) {
-    const char *Name = LLVMGetValueName(SrcCur);
-    LLVMSetValueName(DstCur, Name);
+    size_t NameLen;
+    const char *Name = LLVMValueGetName(SrcCur, &NameLen);
+    LLVMValueSetName(DstCur, Name, NameLen);
 
     VMap[SrcCur] = DstCur;
 
     Count--;
     SrcNext = LLVMGetNextParam(SrcCur);
     DstNext = LLVMGetNextParam(DstCur);
     if (SrcNext == nullptr && DstNext == nullptr) {
       if (SrcCur != SrcLast)

 }
 
 static LLVMValueRef clone_constant_impl(LLVMValueRef Cst, LLVMModuleRef M) {
   if (!LLVMIsAConstant(Cst))
     report_fatal_error("Expected a constant");
 
   // Maybe it is a symbol
   if (LLVMIsAGlobalValue(Cst)) {
-    const char *Name = LLVMGetValueName(Cst);
+    size_t NameLen;
+    const char *Name = LLVMValueGetName(Cst, &NameLen);
 
     // Try function
     if (LLVMIsAFunction(Cst)) {
       check_value_kind(Cst, LLVMFunctionValueKind);
       LLVMValueRef Dst = LLVMGetNamedFunction(M, Name);
       if (Dst)
         return Dst;
       report_fatal_error("Could not find function");
void CloneAttrs(LLVMValueRef Src, LLVMValueRef Dst) {
     }
   }
 
   LLVMValueRef CloneInstruction(LLVMValueRef Src, LLVMBuilderRef Builder) {
     check_value_kind(Src, LLVMInstructionValueKind);
     if (!LLVMIsAInstruction(Src))
       report_fatal_error("Expected an instruction");
 
-    const char *Name = LLVMGetValueName(Src);
+    size_t NameLen;
+    const char *Name = LLVMValueGetName(Src, &NameLen);
 
     // Check if this is something we already computed.
     {
       auto i = VMap.find(Src);
       if (i != VMap.end()) {
         // If we have a hit, it means we already generated the instruction
         // as a dependancy to somethign else. We need to make sure
         // it is ordered properly.
// Check if this is something we already computed.
       }
     }
 
     LLVMValueRef V = LLVMBasicBlockAsValue(Src);
     if (!LLVMValueIsBasicBlock(V) || LLVMValueAsBasicBlock(V) != Src)
       report_fatal_error("Basic block is not a basic block");
 
     const char *Name = LLVMGetBasicBlockName(Src);
-    const char *VName = LLVMGetValueName(V);
+    size_t NameLen;
+    const char *VName = LLVMValueGetName(V, &NameLen);
     if (Name != VName)
       report_fatal_error("Basic block name mismatch");
 
     LLVMBasicBlockRef BB = LLVMAppendBasicBlock(Fun, Name);
     return BBMap[Src] = BB;
   }
 
   LLVMBasicBlockRef CloneBB(LLVMBasicBlockRef Src) {
static void declare_symbols(LLVMModuleRef Src, LLVMModuleRef M) {
   LLVMValueRef Next = nullptr;
   if (!Begin) {
     if (End != nullptr)
       report_fatal_error("Range has an end but no beginning");
     goto FunDecl;
   }
 
   while (true) {
-    const char *Name = LLVMGetValueName(Cur);
+    size_t NameLen;
+    const char *Name = LLVMValueGetName(Cur, &NameLen);
     if (LLVMGetNamedGlobal(M, Name))
       report_fatal_error("GlobalVariable already cloned");
     LLVMAddGlobal(M, LLVMGetElementType(TypeCloner(M).Clone(Cur)), Name);
 
     Next = LLVMGetNextGlobal(Cur);
     if (Next == nullptr) {
       if (Cur != End)
         report_fatal_error("");
if (!Begin) {
     return;
   }
 
   auto Ctx = LLVMGetModuleContext(M);
 
   Cur = Begin;
   Next = nullptr;
   while (true) {
-    const char *Name = LLVMGetValueName(Cur);
+    size_t NameLen;
+    const char *Name = LLVMValueGetName(Cur, &NameLen);
     if (LLVMGetNamedFunction(M, Name))
       report_fatal_error("Function already cloned");
     auto Ty = LLVMGetElementType(TypeCloner(M).Clone(Cur));
     auto F = LLVMAddFunction(M, Name, Ty);
 
     // Copy attributes
     for (int i = LLVMAttributeFunctionIndex, c = LLVMCountParams(F);
          i <= c; ++i) {
static void clone_symbols(LLVMModuleRef Src, LLVMModuleRef M) {
   LLVMValueRef Next = nullptr;
   if (!Begin) {
     if (End != nullptr)
       report_fatal_error("Range has an end but no beginning");
     goto FunClone;
   }
 
   while (true) {
-    const char *Name = LLVMGetValueName(Cur);
+    size_t NameLen;
+    const char *Name = LLVMValueGetName(Cur, &NameLen);
     LLVMValueRef G = LLVMGetNamedGlobal(M, Name);
     if (!G)
       report_fatal_error("GlobalVariable must have been declared already");
 
     if (auto I = LLVMGetInitializer(Cur))
       LLVMSetInitializer(G, clone_constant(I, M));
 
     LLVMSetGlobalConstant(G, LLVMIsGlobalConstant(Cur));
if (!Begin) {
     if (End != nullptr)
       report_fatal_error("Range has an end but no beginning");
     return;
   }
 
   Cur = Begin;
   Next = nullptr;
   while (true) {
-    const char *Name = LLVMGetValueName(Cur);
+    size_t NameLen;
+    const char *Name = LLVMValueGetName(Cur, &NameLen);
     LLVMValueRef Fun = LLVMGetNamedFunction(M, Name);
     if (!Fun)
       report_fatal_error("Function must have been declared already");
 
     if (LLVMHasPersonalityFn(Cur)) {
-      const char *FName = LLVMGetValueName(LLVMGetPersonalityFn(Cur));
+      size_t FNameLen;
+      const char *FName = LLVMValueGetName(LLVMGetPersonalityFn(Cur),
+                                           &FNameLen);
       LLVMValueRef P = LLVMGetNamedFunction(M, FName);
       if (!P)
         report_fatal_error("Could not find personality function");
       LLVMSetPersonalityFn(Fun, P);
     }
 
     FunCloner FC(Cur, Fun);
     FC.CloneBBs(Cur);