MemoryBuiltins: simplify isLibFreeFunction

[durin42]

Summary

This is in anticipation of my next patch, where I need to store more
information about free functions than just their argument count. It felt
invasive enough on this function that it seemed worthwhile to just
extract this as its own commit that makes no functional changes.

[durin42]

(My next patch isn't actually done yet, but I figured I'd get this out for review early since it doesn't seem harmful on its own and I felt like was a nice cleanup of the function.)

[reames]

LGTM, seems reasonable.

[eopXD]

Nit: Adjust commit topic with [NFC] tag.

[durin42]

Done. I don't have commit access, so if someone can push this I'd appreciate it. :)

[durin42]

Reformatted table in anticipation of my next patch, which will embiggen the table enough that clang-format makes a mess of it.

[nikic]

llvm/lib/Analysis/MemoryBuiltins.cpp

440

on?

[durin42]

Fixed typo s/off/on/ in a clang-format directive. Sigh.

[durin42]

llvm/lib/Analysis/MemoryBuiltins.cpp

440

Yep, I spotted that right after I hit submit. 🤦

llvm/lib/Analysis/MemoryBuiltins.cpp

Constant *llvm::getInitialValueOfAllocation(const CallBase *Alloc,
 
   // calloc zero initializes
   if (isCallocLikeFn(Alloc, TLI))
     return Constant::getNullValue(Ty);
 
   return nullptr;
 }
 
+struct FreeFnsTy {
+  unsigned NumParams;
+};
+
+// clang-format off
+static const std::pair<LibFunc, FreeFnsTy> FreeFnData[] = {
+    {LibFunc_free,                               {1}},
+    {LibFunc_ZdlPv,                              {1}}, // operator delete(void*)
+    {LibFunc_ZdaPv,                              {1}}, // operator delete[](void*)
+    {LibFunc_msvc_delete_ptr32,                  {1}}, // operator delete(void*)
+    {LibFunc_msvc_delete_ptr64,                  {1}}, // operator delete(void*)
+    {LibFunc_msvc_delete_array_ptr32,            {1}}, // operator delete[](void*)
+    {LibFunc_msvc_delete_array_ptr64,            {1}}, // operator delete[](void*)
+    {LibFunc_ZdlPvj,                             {2}}, // delete(void*, uint)
+    {LibFunc_ZdlPvm,                             {2}}, // delete(void*, ulong)
+    {LibFunc_ZdlPvRKSt9nothrow_t,                {2}}, // delete(void*, nothrow)
+    {LibFunc_ZdlPvSt11align_val_t,               {2}}, // delete(void*, align_val_t)
+    {LibFunc_ZdaPvj,                             {2}}, // delete[](void*, uint)
+    {LibFunc_ZdaPvm,                             {2}}, // delete[](void*, ulong)
+    {LibFunc_ZdaPvRKSt9nothrow_t,                {2}}, // delete[](void*, nothrow)
+    {LibFunc_ZdaPvSt11align_val_t,               {2}}, // delete[](void*, align_val_t)
+    {LibFunc_msvc_delete_ptr32_int,              {2}}, // delete(void*, uint)
+    {LibFunc_msvc_delete_ptr64_longlong,         {2}}, // delete(void*, ulonglong)
+    {LibFunc_msvc_delete_ptr32_nothrow,          {2}}, // delete(void*, nothrow)
+    {LibFunc_msvc_delete_ptr64_nothrow,          {2}}, // delete(void*, nothrow)
+    {LibFunc_msvc_delete_array_ptr32_int,        {2}}, // delete[](void*, uint)
+    {LibFunc_msvc_delete_array_ptr64_longlong,   {2}}, // delete[](void*, ulonglong)
+    {LibFunc_msvc_delete_array_ptr32_nothrow,    {2}}, // delete[](void*, nothrow)
+    {LibFunc_msvc_delete_array_ptr64_nothrow,    {2}}, // delete[](void*, nothrow)
+    {LibFunc___kmpc_free_shared,                 {2}}, // OpenMP Offloading RTL free
+    {LibFunc_ZdlPvSt11align_val_tRKSt9nothrow_t, {3}}, // delete(void*, align_val_t, nothrow)
+    {LibFunc_ZdaPvSt11align_val_tRKSt9nothrow_t, {3}}, // delete[](void*, align_val_t, nothrow)
+    {LibFunc_ZdlPvjSt11align_val_t,              {3}}, // delete(void*, unsigned int, align_val_t)
+    {LibFunc_ZdlPvmSt11align_val_t,              {3}}, // delete(void*, unsigned long, align_val_t)
+    {LibFunc_ZdaPvjSt11align_val_t,              {3}}, // delete[](void*, unsigned int, align_val_t)
+    {LibFunc_ZdaPvmSt11align_val_t,              {3}}, // delete[](void*, unsigned long, align_val_t)
+};
+// clang-format on
+
 /// isLibFreeFunction - Returns true if the function is a builtin free()
 bool llvm::isLibFreeFunction(const Function *F, const LibFunc TLIFn) {
-  unsigned ExpectedNumParams;
-  if (TLIFn == LibFunc_free ||
-      TLIFn == LibFunc_ZdlPv || // operator delete(void*)
-      TLIFn == LibFunc_ZdaPv || // operator delete[](void*)
-      TLIFn == LibFunc_msvc_delete_ptr32 || // operator delete(void*)
-      TLIFn == LibFunc_msvc_delete_ptr64 || // operator delete(void*)
-      TLIFn == LibFunc_msvc_delete_array_ptr32 || // operator delete[](void*)
-      TLIFn == LibFunc_msvc_delete_array_ptr64)   // operator delete[](void*)
-    ExpectedNumParams = 1;
-  else if (TLIFn == LibFunc_ZdlPvj ||              // delete(void*, uint)
-           TLIFn == LibFunc_ZdlPvm ||              // delete(void*, ulong)
-           TLIFn == LibFunc_ZdlPvRKSt9nothrow_t || // delete(void*, nothrow)
-           TLIFn == LibFunc_ZdlPvSt11align_val_t || // delete(void*, align_val_t)
-           TLIFn == LibFunc_ZdaPvj ||              // delete[](void*, uint)
-           TLIFn == LibFunc_ZdaPvm ||              // delete[](void*, ulong)
-           TLIFn == LibFunc_ZdaPvRKSt9nothrow_t || // delete[](void*, nothrow)
-           TLIFn == LibFunc_ZdaPvSt11align_val_t || // delete[](void*, align_val_t)
-           TLIFn == LibFunc_msvc_delete_ptr32_int ||      // delete(void*, uint)
-           TLIFn == LibFunc_msvc_delete_ptr64_longlong || // delete(void*, ulonglong)
-           TLIFn == LibFunc_msvc_delete_ptr32_nothrow || // delete(void*, nothrow)
-           TLIFn == LibFunc_msvc_delete_ptr64_nothrow || // delete(void*, nothrow)
-           TLIFn == LibFunc_msvc_delete_array_ptr32_int ||      // delete[](void*, uint)
-           TLIFn == LibFunc_msvc_delete_array_ptr64_longlong || // delete[](void*, ulonglong)
-           TLIFn == LibFunc_msvc_delete_array_ptr32_nothrow || // delete[](void*, nothrow)
-           TLIFn == LibFunc_msvc_delete_array_ptr64_nothrow || // delete[](void*, nothrow)
-           TLIFn == LibFunc___kmpc_free_shared) // OpenMP Offloading RTL free
-    ExpectedNumParams = 2;
-  else if (TLIFn == LibFunc_ZdaPvSt11align_val_tRKSt9nothrow_t || // delete(void*, align_val_t, nothrow)
-           TLIFn == LibFunc_ZdlPvSt11align_val_tRKSt9nothrow_t || // delete[](void*, align_val_t, nothrow)
-           TLIFn == LibFunc_ZdlPvjSt11align_val_t || // delete(void*, unsigned long, align_val_t)
-           TLIFn == LibFunc_ZdlPvmSt11align_val_t || // delete(void*, unsigned long, align_val_t)
-           TLIFn == LibFunc_ZdaPvjSt11align_val_t || // delete[](void*, unsigned int, align_val_t)
-           TLIFn == LibFunc_ZdaPvmSt11align_val_t) // delete[](void*, unsigned long, align_val_t)
-    ExpectedNumParams = 3;
-  else
+  const auto *Iter =
+      find_if(FreeFnData, [TLIFn](const std::pair<LibFunc, FreeFnsTy> &P) {
+        return P.first == TLIFn;
+      });
+  if (Iter == std::end(FreeFnData)) {
     return false;
+  }
+  const FreeFnsTy *FnData = &Iter->second;
 
   // Check free prototype.
   // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
   // attribute will exist.
   FunctionType *FTy = F->getFunctionType();
   if (!FTy->getReturnType()->isVoidTy())
     return false;
-  if (FTy->getNumParams() != ExpectedNumParams)
+  if (FTy->getNumParams() != FnData->NumParams)
     return false;
   if (FTy->getParamType(0) != Type::getInt8PtrTy(F->getContext()))
     return false;
 
   return true;
 }
 
 /// isFreeCall - Returns non-null if the value is a call to the builtin free()