Add a new RewriteRope data structure which is a smarter way to represent the text
backing a rewrite buffer than using an std::vector<char>. This class was hacked
together very quickly and needs to be cleaned up, but it seems to work. It speeds
up rewriting a a 7M file from 6.43s to 0.24s on my machine. The impl could also
be made to be a lot more algorithmically sound.
This produces identical output to using vector on this testcase, if it causes a
problems or bugs are encountered, it can be disabled by changing the
RewriteBuffer::Buffer typedef back.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@43884 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Rewrite/Rewriter.cpp b/Rewrite/Rewriter.cpp
index 1df169a..3a007f3 100644
--- a/Rewrite/Rewriter.cpp
+++ b/Rewrite/Rewriter.cpp
@@ -120,6 +120,11 @@
unsigned RealOffset = getMappedOffset(OrigOffset, true);
assert(RealOffset+OrigLength <= Buffer.size() && "Invalid location");
+ Buffer.erase(Buffer.begin()+RealOffset, Buffer.begin()+RealOffset+OrigLength);
+ Buffer.insert(Buffer.begin()+RealOffset, NewStr, NewStr+NewLength);
+ AddDelta(OrigOffset, NewLength-OrigLength);
+ return;
+
// Overwrite the common piece.
unsigned CommonLength = std::min(OrigLength, NewLength);
std::copy(NewStr, NewStr+CommonLength, Buffer.begin()+RealOffset);