[PATCH] D115382: ADT: Avoid using SmallVector::set_size() in SmallString

[Duncan P. N. Exon Smith via Phabricator via llvm-commits]

dexonsmith created this revision.
dexonsmith added a reviewer: dblaikie.
dexonsmith requested review of this revision.
Herald added a project: LLVM.

Update `SmallString::append()` to use `resize_for_overwrite()` instead
of `reserve()` followed by `set_size()`.

A step toward https://reviews.llvm.org/D115380.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D115382

Files:
  llvm/include/llvm/ADT/SmallString.h


Index: llvm/include/llvm/ADT/SmallString.h
===================================================================
--- llvm/include/llvm/ADT/SmallString.h
+++ llvm/include/llvm/ADT/SmallString.h
@@ -73,13 +73,14 @@
     size_t SizeNeeded = this->size();
     for (const StringRef &Ref : Refs)
       SizeNeeded += Ref.size();
-    this->reserve(SizeNeeded);
-    auto CurEnd = this->end();
+    size_t CurrentSize = SizeNeeded;
+    this->resize_for_overwrite(SizeNeeded);
     for (const StringRef &Ref : Refs) {
-      this->uninitialized_copy(Ref.begin(), Ref.end(), CurEnd);
-      CurEnd += Ref.size();
+      this->uninitialized_copy(Ref.begin(), Ref.end(),
+                               this->begin() + CurrentSize);
+      CurrentSize += Ref.size();
     }
-    this->set_size(SizeNeeded);
+    assert(CurrentSize == this->size());
   }
 
   /// @}


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