From d19dcb671529004ecd8a06e38a00d9b8fb380ccd Mon Sep 17 00:00:00 2001 From: Ken Raeburn Date: Wed, 18 Oct 1995 21:21:38 +0000 Subject: [PATCH] Use one active frag and one obstack per frag chain: * frags.c (frags): Variable deleted. (frag_alloc): New function. (frag_grow, frag_more, frag_variant, frag_now_fix, frag_append_1_char): Refer to frchain_now->frch_obstack instead of frags variable. (frag_new): Ditto. Verify that frch_last and frag_now match on entry and exit, and that old frag_now has non-zero type. Replace "know" uses with "assert". Use frag_alloc instead of mucking with obstack alignment. * frags.h (frags): Declaration deleted. * subsegs.h (struct frchain): Add new field frch_frag_now. * subsegs.c (frchains, dummy_frag, absolute_frchain): New static variables. (subsegs_begin): Initialize frchains obstack. Under gcc, don't give it any stricter alignment than frchainS structures need. Do not initialize frags obstack. Set frag_now to point to dummy_obstack. Initialize absolute_frchain. (subseg_set_rest): Save and restore frag_now in frch_frag_now field of frchainS. Don't create new frags on section switch, and use frag_alloc when creating a new frag chain. For absolute section, set frchain_now to absolute_frchain. Verify that frch_last and frag_now match on entry and exit. Initialize per-chain obstack, and under gcc, set required alignment to that needed by fragS structure. * write.c (chain_frchains_together_1): Verify fr_type is nonzero. In one test case of Mike's (i386-linux, over 300K lines of .s code with lots of stabs records), run time and memory use are reduced by about 1/3. Might introduce some problems in cases that use the frag obstacks in unusual ways. Test suite does pass for i386-linux and sparc-solaris targets though. --- gas/subsegs.c | 115 +++++++++++++++++++++++++++++----------------------------- 1 file changed, 57 insertions(+), 58 deletions(-) diff --git a/gas/subsegs.c b/gas/subsegs.c index e360d32..3280bcd 100644 --- a/gas/subsegs.c +++ b/gas/subsegs.c @@ -29,6 +29,8 @@ frchainS *frchain_root, *frchain_now; +static struct obstack frchains; + #ifndef BFD_ASSEMBLER #ifdef MANY_SEGMENTS segment_info_type segment_info[SEG_MAXIMUM_ORDINAL]; @@ -67,6 +69,10 @@ static segment_info_type *und_seg_info; #endif /* BFD_ASSEMBLER */ static void subseg_set_rest PARAMS ((segT, subsegT)); + +static fragS dummy_frag; + +static frchainS absolute_frchain; void subsegs_begin () @@ -87,16 +93,17 @@ subsegs_begin () know (SEG_MAXIMUM_ORDINAL == SEG_REGISTER); #endif + obstack_begin (&frchains, chunksize); +#if __GNUC__ >= 2 + obstack_alignment_mask (&frchains) = __alignof__ (frchainS) - 1; +#endif + frchain_root = NULL; frchain_now = NULL; /* Warn new_subseg() that we are booting. */ - /* Fake up 1st frag. It won't be used=> is ok if obstack... - pads the end of it for alignment. */ - frag_now = (fragS *) obstack_alloc (&frags, SIZEOF_STRUCT_FRAG); - memset (frag_now, 0, SIZEOF_STRUCT_FRAG); + + frag_now = &dummy_frag; #ifndef BFD_ASSEMBLER - /* This 1st frag will not be in any frchain. - We simply give subseg_new somewhere to scribble. */ now_subseg = 42; /* Lie for 1st call to subseg_new. */ #ifdef MANY_SEGMENTS { @@ -117,6 +124,11 @@ subsegs_begin () #endif /* ! MANY_SEGMENTS */ #endif /* ! BFD_ASSEMBLER */ + absolute_frchain.frch_seg = absolute_section; + absolute_frchain.frch_subseg = 0; + absolute_frchain.fix_root = absolute_frchain.fix_tail = 0; + absolute_frchain.frch_frag_now = &zero_address_frag; + absolute_frchain.frch_root = absolute_frchain.frch_last = &zero_address_frag; } /* @@ -137,6 +149,9 @@ subseg_change (seg, subseg) now_seg = seg; now_subseg = subseg; + if (now_seg == absolute_section) + return; + #ifdef BFD_ASSEMBLER { segment_info_type *seginfo; @@ -195,26 +210,29 @@ subseg_set_rest (seg, subseg) register fragS *former_last_fragP; register fragS *new_fragP; - if (frag_now) /* If not bootstrapping. */ + mri_common_symbol = NULL; + + if (frag_now && frchain_now) + frchain_now->frch_frag_now = frag_now; + + assert (frchain_now == 0 + || now_seg == undefined_section + || now_seg == absolute_section + || frchain_now->frch_last == frag_now); + + subseg_change (seg, (int) subseg); + + if (seg == absolute_section) { - frag_now->fr_fix = frag_now_fix (); - frag_wane (frag_now); /* Close off any frag in old subseg. */ + frchain_now = &absolute_frchain; + frag_now = &zero_address_frag; + return; } - /* - * It would be nice to keep an obstack for each subsegment, if we swap - * subsegments a lot. Hence we would have much fewer frag_wanes(). - */ - { - obstack_finish (&frags); - /* - * If we don't do the above, the next object we put on obstack frags - * will appear to start at the fr_literal of the current frag. - * Also, above ensures that the next object will begin on a - * address that is aligned correctly for the engine that runs - * this program. - */ - } - subseg_change (seg, (int) subseg); + + assert (frchain_now == 0 + || now_seg == undefined_section + || frchain_now->frch_last == frag_now); + /* * Attempt to find or make a frchain for that sub seg. * Crawl along chain of frchainSs, begins @ frchain_root. @@ -259,16 +277,22 @@ subseg_set_rest (seg, subseg) /* * This should be the only code that creates a frchainS. */ - newP = (frchainS *) obstack_alloc (&frags, sizeof (frchainS)); - newP->frch_root = 0; + extern fragS *frag_alloc (); + newP = (frchainS *) obstack_alloc (&frchains, sizeof (frchainS)); newP->frch_subseg = subseg; newP->frch_seg = seg; - newP->frch_last = NULL; #ifdef BFD_ASSEMBLER newP->fix_root = NULL; newP->fix_tail = NULL; #endif obstack_begin (&newP->frch_obstack, 5000); +#if __GNUC__ >= 2 + obstack_alignment_mask (&newP->frch_obstack) = __alignof__ (fragS) - 1; +#endif + newP->frch_frag_now = frag_alloc (&newP->frch_obstack); + newP->frch_frag_now->fr_type = rs_fill; + + newP->frch_root = newP->frch_last = newP->frch_frag_now; *lastPP = newP; newP->frch_next = frcP; /* perhaps NULL */ @@ -278,37 +302,9 @@ subseg_set_rest (seg, subseg) * Here with frcP pointing to the frchainS for subseg. */ frchain_now = frcP; - /* - * Make a fresh frag for the subsegment. - */ - /* We expect this to happen on a correct boundary since it was - proceeded by a obstack_done(). */ - tmp = obstack_alignment_mask (&frags); /* JF disable alignment */ - obstack_alignment_mask (&frags) = 0; - frag_now = (fragS *) obstack_alloc (&frags, SIZEOF_STRUCT_FRAG); - memset (frag_now, 0, SIZEOF_STRUCT_FRAG); - obstack_alignment_mask (&frags) = tmp; - /* But we want any more chars to come immediately after the - structure we just made. */ - new_fragP = frag_now; - new_fragP->fr_next = NULL; - /* - * Append new frag to current frchain. - */ - former_last_fragP = frcP->frch_last; - if (former_last_fragP) - { - know (former_last_fragP->fr_next == NULL); - know (frchain_now->frch_root); - former_last_fragP->fr_next = new_fragP; - } - else - { - frcP->frch_root = new_fragP; - } - frcP->frch_last = new_fragP; + frag_now = frcP->frch_frag_now; - mri_common_symbol = NULL; + assert (frchain_now->frch_last == frag_now); } /* @@ -379,7 +375,10 @@ subseg_set (seg, subseg) /* begin assembly for a new sub-segment */ register subsegT subseg; { #ifndef MANY_SEGMENTS - know (seg == SEG_DATA || seg == SEG_TEXT || seg == SEG_BSS); + know (seg == SEG_DATA + || seg == SEG_TEXT + || seg == SEG_BSS + || seg == SEG_ABSOLUTE); #endif if (seg != now_seg || subseg != now_subseg) -- 2.7.4