llvm-6502/lib/MC/MCParser
Kevin Enderby a89594947e Improve the time it takes to generating dwarf for assembly source files
that have been run through the 'C' pre-processor.

The implementation of SrcMgr.FindLineNumber() is slow but OK if
it uses its cache when called multiple times with an SMLoc that is
forward of the previous call.

In the case of generating dwarf for assembly source files that have
been run through the 'C' pre-processor we need to calculate the
logical line number based on the last parsed cpp hash file line
comment.  And the current code calls SrcMgr.FindLineNumber()
twice to do this causing its cache not to work and results in very
slow compile times:

% time /Volumes/SandBox/build-llvm/Debug+Asserts/bin/llvm-mc -triple thumbv7-apple-ios -filetype=obj -o /tmp/x.o mscorlib.dll.E -g
672.542u 0.299s 11:13.15 99.9%	0+0k 0+2io 2106pf+0w

So we save the info from the last parsed cpp hash file line comment
to avoid making the second call to SrcMgr.FindLineNumber() most times
and end up with compile times like:

% time /Volumes/SandBox/build-llvm/Debug+Asserts/bin/llvm-mc -triple thumbv7-apple-ios -filetype=obj -o /tmp/x.o mscorlib.dll.E -g
3.404u 0.104s 0:03.80 92.1%	0+0k 0+3io 2105pf+0w

rdar://14156934


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184592 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-21 20:51:39 +00:00
..
AsmLexer.cpp AsmParser: More generic support for integer type suffices. 2013-02-26 20:17:10 +00:00
AsmParser.cpp Improve the time it takes to generating dwarf for assembly source files 2013-06-21 20:51:39 +00:00
CMakeLists.txt build/CMake: Finish removal of add_llvm_library_dependencies. 2011-11-29 19:25:30 +00:00
COFFAsmParser.cpp Use pointers to the MCAsmInfo and MCRegInfo. 2013-06-18 07:20:20 +00:00
DarwinAsmParser.cpp Add support for subsections to the ELF assembler. Fixes PR8717. 2013-04-17 21:18:16 +00:00
ELFAsmParser.cpp Add support for subsections to the ELF assembler. Fixes PR8717. 2013-04-17 21:18:16 +00:00
LLVMBuild.txt LLVMBuild: Remove trailing newline, which irked me. 2011-12-12 19:48:00 +00:00
Makefile
MCAsmLexer.cpp Change SMRange to be half-open (exclusive end) instead of closed (inclusive) 2013-01-07 19:00:49 +00:00
MCAsmParser.cpp MCParser: Update method names per coding guidelines. 2013-02-20 22:21:35 +00:00
MCAsmParserExtension.cpp Restore r125595 (reverted in r126336) with modifications: 2011-02-24 21:59:22 +00:00
MCTargetAsmParser.cpp [ms-inline asm] Add the isParsingInlineAsm() function to the MCAsmTargetParser. 2012-10-19 17:57:49 +00:00