[llvm-jitlink] Only use delta-mapper when needed, always onor slab-size.

[lhames]

Summary

The delta mapper should only be needed in -no-exec mode if the slab address or slab page size are set. Otherwise we can use the regular in-process mapper, just passing in the requested slab size (or a default).

[argentite]

Thanks!

llvm/tools/llvm-jitlink/llvm-jitlink.cpp

 }
 
 static std::unique_ptr<JITLinkMemoryManager> createInProcessMemoryManager() {
-  if (!SlabAllocateSizeString.empty()) {
-    auto SlabSize = ExitOnErr(getSlabAllocSize(SlabAllocateSizeString));
 
+#ifdef _WIN32
+  size_t SlabSize = 1024 * 1024;
+#else
+  size_t SlabSize = 1024 * 1024 * 1024;
+#endif
+
+  if (!SlabAllocateSizeString.empty())
+    SlabSize = ExitOnErr(getSlabAllocSize(SlabAllocateSizeString));
+
+  if (NoExec && (SlabAddress || SlabPageSize))
     return ExitOnErr(
         MapperJITLinkMemoryManager::CreateWithMapper<InProcessDeltaMapper>(
             SlabSize));
-  }
 
-#ifdef _WIN32
   return ExitOnErr(
       MapperJITLinkMemoryManager::CreateWithMapper<InProcessMemoryMapper>(
-          1024 * 1024));
-#else
-  return ExitOnErr(
-      MapperJITLinkMemoryManager::CreateWithMapper<InProcessMemoryMapper>(
-          1024 * 1024 * 1024));
-#endif
+          SlabSize));
 }
 
 Expected<std::unique_ptr<jitlink::JITLinkMemoryManager>>