<div dir="ltr"><div class="gmail_quote"><div dir="ltr">On Tue, May 22, 2018 at 12:29 PM Fāng-ruì Sòng <<a href="mailto:maskray@google.com">maskray@google.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">OK. <div><br><div><div style="color:rgb(34,34,34);font-family:sans-serif;font-size:13px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="color:rgb(34,34,34);font-family:sans-serif;font-size:13px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">if (Name.startswith(Prefix))</span><br></div><div style="color:rgb(34,34,34);font-family:sans-serif;font-size:13px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="color:rgb(34,34,34);font-family:sans-serif;font-size:13px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">  DoSomethingWith(Name.</span><span style="color:rgb(34,34,34);font-family:sans-serif;font-size:13px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">substr(Prefix.size())))</span></div><br class="m_-8563715784572447538gmail-Apple-interchange-newline"><span style="color:rgb(34,34,34);font-family:sans-serif;font-size:13px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">should be acceptable. What if an integer constant is used?</span><br></div><div><br><div><span style="color:rgb(34,34,34);font-family:sans-serif;font-size:13px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">if (Name.startswith("__start_"))</span><br></div><div><span style="color:rgb(34,34,34);font-family:sans-serif;font-size:13px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">  DoSomethingWith(Name.</span><span style="color:rgb(34,34,34);font-family:sans-serif;font-size:13px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">substr(8)))</span></div></div></div></div></blockquote><div><br></div><div>I can't speak for everybody, but I do accept that as long as it is obvious what you are trying to do with the code.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="gmail_quote"><div dir="ltr">On Tue, May 22, 2018 at 9:02 AM Rui Ueyama <<a href="mailto:ruiu@google.com" target="_blank">ruiu@google.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">This is somewhat arguable whether this simplifies the code or not because in most (perhaps all?) places in lld, StringRefs are handled as an immutable (or initialize-once) object. We don't usually use StringRef's member functions that mutates the internal state of the object. If you read lld's code, I think you'd notice that we usually create a new StringRef object when we need a substring, even if it seems a bit inefficient. I believe that makes the code easier to understand as mutating an object sometimes creates confusion.<br></div><br><div class="gmail_quote"><div dir="ltr">On Mon, May 21, 2018 at 11:31 PM Fangrui Song via llvm-commits <<a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: maskray<br>
Date: Mon May 21 23:28:00 2018<br>
New Revision: 332952<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=332952&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project?rev=332952&view=rev</a><br>
Log:<br>
[ELF] Simplify. NFC<br>
<br>
Modified:<br>
    lld/trunk/ELF/LTO.cpp<br>
<br>
Modified: lld/trunk/ELF/LTO.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LTO.cpp?rev=332952&r1=332951&r2=332952&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LTO.cpp?rev=332952&r1=332951&r2=332952&view=diff</a><br>
==============================================================================<br>
--- lld/trunk/ELF/LTO.cpp (original)<br>
+++ lld/trunk/ELF/LTO.cpp Mon May 21 23:28:00 2018<br>
@@ -155,8 +155,8 @@ BitcodeCompiler::BitcodeCompiler() {<br>
   for (Symbol *Sym : Symtab->getSymbols()) {<br>
     StringRef Name = Sym->getName();<br>
     for (StringRef Prefix : {"__start_", "__stop_"})<br>
-      if (Name.startswith(Prefix))<br>
-        UsedStartStop.insert(Name.substr(Prefix.size()));<br>
+      if (Name.consume_front(Prefix))<br>
+        UsedStartStop.insert(Name);<br>
   }<br>
 }<br>
<br>
<br>
<br>
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</blockquote></div>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="m_-8563715784572447538gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">宋方睿</div></div>
</blockquote></div></div>