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
include guards don't show up as macro definitions in every translation
unit that imports a module. Macro definitions can, however, be
exported with the intentionally-ugly #__export_macro__
directive. Implement this feature by not even bothering to serialize
non-exported macros to a module, because clients of that module need
not (should not) know that these macros even exist.
llvm-svn: 138943
When a macro instantiation occurs, reserve a SLocEntry chunk with length the
full length of the macro definition source. Set the spelling location of this chunk
to point to the start of the macro definition and any tokens that are lexed directly
from the macro definition will get a location from this chunk with the appropriate offset.
For any tokens that come from argument expansion, '##' paste operator, etc. have their
instantiation location point at the appropriate place in the instantiated macro definition
(the argument identifier and the '##' token respectively).
This improves macro instantiation diagnostics:
Before:
t.c:5:9: error: invalid operands to binary expression ('struct S' and 'int')
int y = M(/);
^~~~
t.c:5:11: note: instantiated from:
int y = M(/);
^
After:
t.c:5:9: error: invalid operands to binary expression ('struct S' and 'int')
int y = M(/);
^~~~
t.c:3:20: note: instantiated from:
\#define M(op) (foo op 3);
~~~ ^ ~
t.c:5:11: note: instantiated from:
int y = M(/);
^
The memory savings for a candidate boost library that abuses the preprocessor are:
- 32% less SLocEntries (37M -> 25M)
- 30% reduction in PCH file size (900M -> 635M)
- 50% reduction in memory usage for the SLocEntry table (1.6G -> 800M)
llvm-svn: 134587
Diagnostic pragmas are broken because we don't keep track of the diagnostic state changes and we only check the current/latest state.
Problems manifest if a diagnostic is emitted for a source line that has different diagnostic state than the current state; this can affect
a lot of places, like C++ inline methods, template instantiations, the lexer, etc.
Fix the issue by having the Diagnostic object keep track of the source location of the pragmas so that it is able to know what is the diagnostic state at any given source location.
Fixes rdar://8365684.
llvm-svn: 121873
lib dir and move all the libraries into it. This follows the main
llvm tree, and allows the libraries to be built in parallel. The
top level now enforces that all the libs are built before Driver,
but we don't care what order the libs are built in. This speeds
up parallel builds, particularly incremental ones.
llvm-svn: 48402
Alexander Kornienko