forked from OSchip/llvm-project
8b3f623582
Summary:
Summary: Keep history of macro definitions and #undefs with corresponding source locations, so that we can later find out all macros active in a specified source location. We don't save the history in PCH (no need currently). Memory overhead is about sizeof(void*)*3*<number of macro definitions and #undefs>+<in-memory size of all #undef'd macros>
I've run a test on a file composed of 109 .h files from boost 1.49 on x86-64 linux.
Stats before this patch:
*** Preprocessor Stats:
73222 directives found:
19171 #define.
4345 #undef.
#include/#include_next/#import:
5233 source files entered.
27 max include stack depth
19210 #if/#ifndef/#ifdef.
2384 #else/#elif.
6891 #endif.
408 #pragma.
14466 #if/#ifndef#ifdef regions skipped
80023/451669/1270 obj/fn/builtin macros expanded, 85724 on the fast path.
127145 token paste (##) operations performed, 11008 on the fast path.
Preprocessor Memory: 5874615B total
BumpPtr: 4399104
Macro Expanded Tokens: 417768
Predefines Buffer: 8135
Macros: 1048576
#pragma push_macro Info: 0
Poison Reasons: 1024
Comment Handlers: 8
Stats with this patch:
...
Preprocessor Memory: 7541687B total
BumpPtr: 6066176
Macro Expanded Tokens: 417768
Predefines Buffer: 8135
Macros: 1048576
#pragma push_macro Info: 0
Poison Reasons: 1024
Comment Handlers: 8
In my test increase in memory usage is about 1.7Mb, which is ~28% of initial preprocessor's memory usage and about 0.8% of clang's total VMM allocation.
As for CPU overhead, it should only be noticeable when iterating over all macros, and should mostly consist of couple extra dereferences and one comparison per macro + skipping of #undef'd macros. It's less trivial to measure, though, as the preprocessor consumes a very small fraction of compilation time.
Reviewers: doug.gregor, klimek, rsmith, djasper
Reviewed By: doug.gregor
CC: cfe-commits, chandlerc
Differential Revision: http://llvm-reviews.chandlerc.com/D28
llvm-svn: 162810
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| .. | ||
| AnalysisBasedWarnings.cpp | ||
| AttributeList.cpp | ||
| CMakeLists.txt | ||
| CodeCompleteConsumer.cpp | ||
| DeclSpec.cpp | ||
| DelayedDiagnostic.cpp | ||
| IdentifierResolver.cpp | ||
| JumpDiagnostics.cpp | ||
| Makefile | ||
| Scope.cpp | ||
| Sema.cpp | ||
| SemaAccess.cpp | ||
| SemaAttr.cpp | ||
| SemaCXXScopeSpec.cpp | ||
| SemaCast.cpp | ||
| SemaChecking.cpp | ||
| SemaCodeComplete.cpp | ||
| SemaConsumer.cpp | ||
| SemaDecl.cpp | ||
| SemaDeclAttr.cpp | ||
| SemaDeclCXX.cpp | ||
| SemaDeclObjC.cpp | ||
| SemaExceptionSpec.cpp | ||
| SemaExpr.cpp | ||
| SemaExprCXX.cpp | ||
| SemaExprMember.cpp | ||
| SemaExprObjC.cpp | ||
| SemaFixItUtils.cpp | ||
| SemaInit.cpp | ||
| SemaLambda.cpp | ||
| SemaLookup.cpp | ||
| SemaObjCProperty.cpp | ||
| SemaOverload.cpp | ||
| SemaPseudoObject.cpp | ||
| SemaStmt.cpp | ||
| SemaStmtAsm.cpp | ||
| SemaStmtAttr.cpp | ||
| SemaTemplate.cpp | ||
| SemaTemplateDeduction.cpp | ||
| SemaTemplateInstantiate.cpp | ||
| SemaTemplateInstantiateDecl.cpp | ||
| SemaTemplateVariadic.cpp | ||
| SemaType.cpp | ||
| TargetAttributesSema.cpp | ||
| TargetAttributesSema.h | ||
| TreeTransform.h | ||
| TypeLocBuilder.h | ||