Eric Botcazou - Re: C++ lexical analysis rework (original) (raw)

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• From: Eric Botcazou
• To: Zack Weinberg
• Cc: gcc-patches at gcc dot gnu dot org,Matt Austern ,Steve Naroff
• Date: Sat, 15 Jan 2005 10:50:05 +0100
• Subject: Re: C++ lexical analysis rework
• References: 871xgw4azp.fsf@codesourcery.com

Here is the foreshadowed patch which speeds up the C++ front end's lexical analysis phase. What it does is really quite simple: it has (almost) all of the work that cpplib and c-lex.c do done at once, and holds all the translation unit's tokens in a big buffer.

I just discovered that this breaks DBX_USE_BINCL support:

3.4.x: .stabs "wchar-1.H",130,0,0,0 .stabs "/home/eric/install/gcc-3_4-branch/native/lib/gcc/amd64-mandrake-linux-gnu/3.4.4/include/stddef.h",130,0,0,0 .stabs "ptrdiff_t:t(2,1)=(0,3)",128,0,0,0 .stabs "size_t:t(2,2)=(0,17)",128,0,0,0 .stabn 162,0,0,0 .stabn 162,0,0,0

4.0.0 .stabs "ptrdiff_t:t(0,25)=(0,7)",128,0,0,0 .stabs "size_t:t(0,26)=(0,9)",128,0,0,0

because dbxout.c relies on the ordered invocations of dbxout_start_source_file, dbxout_symbol and dbxout_end_source_file to implement it. Now dbxout_start_source_file and dbxout_end_source_file are invoked by the lexer, while dbxout_symbol is invoked by the parser.

The problem shows up through these failures in the C++ testsuite:

FAIL: g++.dg/pch/externc-1.C -g assembly comparison FAIL: g++.dg/pch/externc-1.C -O2 -g assembly comparison FAIL: g++.dg/pch/static-1.C -g assembly comparison FAIL: g++.dg/pch/static-1.C -O2 -g assembly comparison FAIL: g++.dg/pch/system-1.C -g assembly comparison FAIL: g++.dg/pch/system-1.C -O2 -g assembly comparison FAIL: g++.dg/pch/system-2.C -g assembly comparison FAIL: g++.dg/pch/system-2.C -O2 -g assembly comparison FAIL: g++.dg/pch/uninst.C -g assembly comparison FAIL: g++.dg/pch/uninst.C -O2 -g assembly comparison FAIL: g++.dg/pch/wchar-1.C -g assembly comparison FAIL: g++.dg/pch/wchar-1.C -O2 -g assembly comparison

on e.g. sparc-sun-solaris2.6 and sparc-sun-solaris2.5.1.

How do you think we can fix this? Should we "replay" the opening/closing of files in the parser (if this is ever possible)?

-- Eric Botcazou

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