Author: majnemer
Date: Mon May 16 15:30:03 2016
New Revision: 269687
URL: http://llvm.org/viewvc/llvm-project?rev=269687&view=rev
Log:
[Lex] inferModuleFromLocation should do no work if there are no modules
getModuleContainingLocation ends up on the hot-path for typical C code
which can lead to calls to getFileIDSlow.
To speed this up, short circuit inferModuleFromLocation when there
aren't any modules, implicit or otherwise.
This shaves 4-5% build time when building the linux kernel.
Modified:
cfe/trunk/lib/Lex/ModuleMap.cpp
Modified: cfe/trunk/lib/Lex/ModuleMap.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/ModuleMap.cpp?rev=269687&r1=269686&r2=269687&view=diff
==============================================================================
--- cfe/trunk/lib/Lex/ModuleMap.cpp (original)
+++ cfe/trunk/lib/Lex/ModuleMap.cpp Mon May 16 15:30:03 2016
@@ -917,6 +917,9 @@ Module *ModuleMap::inferModuleFromLocati
if (Loc.isInvalid())
return nullptr;
+ if (UmbrellaDirs.empty() && Headers.empty())
+ return nullptr;
+
// Use the expansion location to determine which module we're in.
FullSourceLoc ExpansionLoc = Loc.getExpansionLoc();
if (!ExpansionLoc.isFileID())
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