From 88fc725d2fa9234fef229e80472740610172421b Mon Sep 17 00:00:00 2001 From: Hans-Peter Nilsson Date: Sat, 18 Oct 2003 15:53:40 +0000 Subject: [PATCH] Generate BFD_RELOC_MMIX_PUSHJ_STUBBABLE for PUSHJ when possible. * doc/c-mmix.texi (MMIX-Opts): Document --no-pushj-stubs and --no-stubs. * config/tc-mmix.c: Include limits.h. Expand on mmix_relax_table comment. (expand_op, mmix_next_semicolon_is_eoln): Fix head comment. (pushj_stubs): New variable. (OPTION_NOPUSHJSTUBS, STATE_PUSHJSTUB, PUSHJSTUB_MIN) (PUSHJSTUB_MAX): New macros. (md_longopts): New options "--no-pushj-stubs" and synonym "--no-stubs". (mmix_relax_table): Handle new entry for STATE_PUSHJSTUB. (md_parse_option): Handle OPTION_NOPUSHJSTUBS. (md_estimate_size_before_relax): Modify STATE_PUSHJ state for PUSHJ stub relaxation. (md_convert_frag): Handle STATE_PUSHJSTUB. (md_apply_fix3): Handle BFD_RELOC_MMIX_PUSHJ_STUBBABLE. (tc_gen_reloc): Ditto. (mmix_md_relax_frag): Handle PUSHJ stub relaxation. * config/tc-mmix.h (TC_SEGMENT_INFO_TYPE): Define. (struct mmix_segment_info_type): New. --- gas/ChangeLog | 24 +++++ gas/config/tc-mmix.c | 212 ++++++++++++++++++++++++++++++++++++++++--- gas/config/tc-mmix.h | 15 ++- gas/doc/c-mmix.texi | 15 +++ 4 files changed, 250 insertions(+), 16 deletions(-) diff --git a/gas/ChangeLog b/gas/ChangeLog index 365fcadb59..59d5928610 100644 --- a/gas/ChangeLog +++ b/gas/ChangeLog @@ -1,3 +1,27 @@ +2003-10-18 Hans-Peter Nilsson + + Generate BFD_RELOC_MMIX_PUSHJ_STUBBABLE for PUSHJ when possible. + * doc/c-mmix.texi (MMIX-Opts): Document --no-pushj-stubs and + --no-stubs. + * config/tc-mmix.c: Include limits.h. Expand on mmix_relax_table + comment. + (expand_op, mmix_next_semicolon_is_eoln): Fix head comment. + (pushj_stubs): New variable. + (OPTION_NOPUSHJSTUBS, STATE_PUSHJSTUB, PUSHJSTUB_MIN) + (PUSHJSTUB_MAX): New macros. + (md_longopts): New options "--no-pushj-stubs" and synonym + "--no-stubs". + (mmix_relax_table): Handle new entry for STATE_PUSHJSTUB. + (md_parse_option): Handle OPTION_NOPUSHJSTUBS. + (md_estimate_size_before_relax): Modify STATE_PUSHJ state for + PUSHJ stub relaxation. + (md_convert_frag): Handle STATE_PUSHJSTUB. + (md_apply_fix3): Handle BFD_RELOC_MMIX_PUSHJ_STUBBABLE. + (tc_gen_reloc): Ditto. + (mmix_md_relax_frag): Handle PUSHJ stub relaxation. + * config/tc-mmix.h (TC_SEGMENT_INFO_TYPE): Define. + (struct mmix_segment_info_type): New. + 2003-10-17 Paul Dale Bernardo Innocenti diff --git a/gas/config/tc-mmix.c b/gas/config/tc-mmix.c index 7483159cdb..1e01b7a3ab 100644 --- a/gas/config/tc-mmix.c +++ b/gas/config/tc-mmix.c @@ -27,6 +27,7 @@ #include +#include #include "as.h" #include "subsegs.h" #include "bfd.h" @@ -143,7 +144,8 @@ struct mmix_symbol_gregs this line? */ static int label_without_colon_this_line = 1; -/* Should we expand operands for external symbols? */ +/* Should we automatically expand instructions into multiple insns in + order to generate working code? */ static int expand_op = 1; /* Should we warn when expanding operands? FIXME: test-cases for when -x @@ -170,8 +172,12 @@ int mmix_gnu_syntax = 0; /* Do we globalize all symbols? */ int mmix_globalize_symbols = 0; +/* When expanding insns, do we want to expand PUSHJ as a call to a stub + (or else as a series of insns)? */ +int pushj_stubs = 1; + /* Do we know that the next semicolon is at the end of the operands field - (in mmixal mode; constant 1 in GNU mode)? */ + (in mmixal mode; constant 1 in GNU mode)? */ int mmix_next_semicolon_is_eoln = 1; /* Do we have a BSPEC in progress? */ @@ -189,6 +195,7 @@ struct option md_longopts[] = #define OPTION_GLOBALIZE_SYMBOLS (OPTION_GNU_SYNTAX + 1) #define OPTION_FIXED_SPEC_REGS (OPTION_GLOBALIZE_SYMBOLS + 1) #define OPTION_LINKER_ALLOCATED_GREGS (OPTION_FIXED_SPEC_REGS + 1) +#define OPTION_NOPUSHJSTUBS (OPTION_LINKER_ALLOCATED_GREGS + 1) {"linkrelax", no_argument, NULL, OPTION_RELAX}, {"no-expand", no_argument, NULL, OPTION_NOEXPAND}, {"no-merge-gregs", no_argument, NULL, OPTION_NOMERGEGREG}, @@ -199,6 +206,8 @@ struct option md_longopts[] = OPTION_FIXED_SPEC_REGS}, {"linker-allocated-gregs", no_argument, NULL, OPTION_LINKER_ALLOCATED_GREGS}, + {"no-pushj-stubs", no_argument, NULL, OPTION_NOPUSHJSTUBS}, + {"no-stubs", no_argument, NULL, OPTION_NOPUSHJSTUBS}, {NULL, no_argument, NULL, 0} }; @@ -227,15 +236,27 @@ struct obstack mmix_sym_obstack; 3. PUSHJ extra length: zero or four insns. + Special handling to deal with transition to PUSHJSTUB. 4. JMP - extra length: zero or four insns. */ + extra length: zero or four insns. + + 5. GREG + special handling, allocates a named global register unless another + is within reach for all uses. + + 6. PUSHJSTUB + special handling (mostly) for external references; assumes the + linker will generate a stub if target is no longer than 256k from + the end of the section plus max size of previous stubs. Zero or + four insns. */ #define STATE_GETA (1) #define STATE_BCC (2) #define STATE_PUSHJ (3) #define STATE_JMP (4) #define STATE_GREG (5) +#define STATE_PUSHJSTUB (6) /* No fine-grainedness here. */ #define STATE_LENGTH_MASK (1) @@ -279,6 +300,24 @@ struct obstack mmix_sym_obstack; #define PUSHJ_4F GETA_3F #define PUSHJ_4B GETA_3B +/* We'll very rarely have sections longer than LONG_MAX, but we'll make a + feeble attempt at getting 64-bit C99 or gcc-specific values (assuming + long long is 64 bits on the host). */ +#ifdef LLONG_MIN +#define PUSHJSTUB_MIN LLONG_MIN +#elsif defined (LONG_LONG_MIN) +#define PUSHJSTUB_MIN LONG_LONG_MIN +#else +#define PUSHJSTUB_MIN LONG_MIN +#endif +#ifdef LLONG_MAX +#define PUSHJSTUB_MAX LLONG_MAX +#elsif defined (LONG_LONG_MAX) +#define PUSHJSTUB_MAX LONG_LONG_MAX +#else +#define PUSHJSTUB_MAX LONG_MAX +#endif + #define JMP_0F (65536 * 256 * 4 - 8) #define JMP_0B (-65536 * 256 * 4 - 4) @@ -311,8 +350,8 @@ const relax_typeS mmix_relax_table[] = {BCC_5F, BCC_5B, BCC_MAX_LEN - 4, 0}, - /* PUSHJ (3, 0). */ - {PUSHJ_0F, PUSHJ_0B, 0, ENCODE_RELAX (STATE_PUSHJ, STATE_MAX)}, + /* PUSHJ (3, 0). Next state is actually PUSHJSTUB (6, 0). */ + {PUSHJ_0F, PUSHJ_0B, 0, ENCODE_RELAX (STATE_PUSHJSTUB, STATE_ZERO)}, /* PUSHJ (3, 1). */ {PUSHJ_4F, PUSHJ_4B, @@ -326,7 +365,13 @@ const relax_typeS mmix_relax_table[] = JMP_MAX_LEN - 4, 0}, /* GREG (5, 0), (5, 1), though the table entry isn't used. */ - {0, 0, 0, 0}, {0, 0, 0, 0} + {0, 0, 0, 0}, {0, 0, 0, 0}, + + /* PUSHJSTUB (6, 0). PUSHJ (3, 0) uses the range, so we set it to infinite. */ + {PUSHJSTUB_MAX, PUSHJSTUB_MIN, + 0, ENCODE_RELAX (STATE_PUSHJ, STATE_MAX)}, + /* PUSHJSTUB (6, 1) isn't used. */ + {0, 0, PUSHJ_MAX_LEN, 0} }; const pseudo_typeS md_pseudo_table[] = @@ -661,6 +706,10 @@ md_parse_option (c, arg) allocate_undefined_gregs_in_linker = 1; break; + case OPTION_NOPUSHJSTUBS: + pushj_stubs = 0; + break; + default: return 0; } @@ -2181,12 +2230,27 @@ md_estimate_size_before_relax (fragP, segment) { HANDLE_RELAXABLE (STATE_GETA); HANDLE_RELAXABLE (STATE_BCC); - HANDLE_RELAXABLE (STATE_PUSHJ); HANDLE_RELAXABLE (STATE_JMP); + case ENCODE_RELAX (STATE_PUSHJ, STATE_UNDF): + if (fragP->fr_symbol != NULL + && S_GET_SEGMENT (fragP->fr_symbol) == segment + && !S_IS_WEAK (fragP->fr_symbol)) + /* The symbol lies in the same segment - a relaxable case. */ + fragP->fr_subtype = ENCODE_RELAX (STATE_PUSHJ, STATE_ZERO); + else if (pushj_stubs) + /* If we're to generate stubs, assume we can reach a stub after + the section. */ + fragP->fr_subtype = ENCODE_RELAX (STATE_PUSHJSTUB, STATE_ZERO); + /* FALLTHROUGH. */ + case ENCODE_RELAX (STATE_PUSHJ, STATE_ZERO): + case ENCODE_RELAX (STATE_PUSHJSTUB, STATE_ZERO): + /* We need to distinguish different relaxation rounds. */ + seg_info (segment)->tc_segment_info_data.last_stubfrag = fragP; + break; + case ENCODE_RELAX (STATE_GETA, STATE_ZERO): case ENCODE_RELAX (STATE_BCC, STATE_ZERO): - case ENCODE_RELAX (STATE_PUSHJ, STATE_ZERO): case ENCODE_RELAX (STATE_JMP, STATE_ZERO): /* When relaxing a section for the second time, we don't need to do anything except making sure that fr_var is set right. */ @@ -2307,6 +2371,16 @@ md_convert_frag (abfd, sec, fragP) switch (fragP->fr_subtype) { + case ENCODE_RELAX (STATE_PUSHJSTUB, STATE_ZERO): + /* Setting the unknown bits to 0 seems the most appropriate. */ + mmix_set_geta_branch_offset (opcodep, 0); + tmpfixP = fix_new (opc_fragP, opcodep - opc_fragP->fr_literal, 8, + fragP->fr_symbol, fragP->fr_offset, 1, + BFD_RELOC_MMIX_PUSHJ_STUBBABLE); + COPY_FR_WHERE_TO_FX (fragP, tmpfixP); + var_part_size = 0; + break; + case ENCODE_RELAX (STATE_GETA, STATE_ZERO): case ENCODE_RELAX (STATE_BCC, STATE_ZERO): case ENCODE_RELAX (STATE_PUSHJ, STATE_ZERO): @@ -2453,6 +2527,7 @@ md_apply_fix3 (fixP, valP, segment) case BFD_RELOC_MMIX_GETA: case BFD_RELOC_MMIX_CBRANCH: case BFD_RELOC_MMIX_PUSHJ: + case BFD_RELOC_MMIX_PUSHJ_STUBBABLE: /* If this fixup is out of range, punt to the linker to emit an error. This should only happen with -no-expand. */ if (val < -(((offsetT) 1 << 19)/2) @@ -2665,6 +2740,7 @@ tc_gen_reloc (section, fixP) case BFD_RELOC_MMIX_PUSHJ_1: case BFD_RELOC_MMIX_PUSHJ_2: case BFD_RELOC_MMIX_PUSHJ_3: + case BFD_RELOC_MMIX_PUSHJ_STUBBABLE: case BFD_RELOC_MMIX_JMP: case BFD_RELOC_MMIX_JMP_1: case BFD_RELOC_MMIX_JMP_2: @@ -3333,13 +3409,121 @@ mmix_md_relax_frag (seg, fragP, stretch) fragS *fragP; long stretch; { - if (fragP->fr_subtype != STATE_GREG_DEF - && fragP->fr_subtype != STATE_GREG_UNDF) - return relax_frag (seg, fragP, stretch); + switch (fragP->fr_subtype) + { + /* Growth for this type has been handled by mmix_md_end and + correctly estimated, so there's nothing more to do here. */ + case STATE_GREG_DEF: + return 0; - /* If we're defined, we don't grow. */ - if (fragP->fr_subtype == STATE_GREG_DEF) - return 0; + case ENCODE_RELAX (STATE_PUSHJ, STATE_ZERO): + { + /* We need to handle relaxation type ourselves, since relax_frag + doesn't update fr_subtype if there's no size increase in the + current section; when going from plain PUSHJ to a stub. This + is otherwise functionally the same as relax_frag in write.c, + simplified for this case. */ + offsetT aim; + addressT target; + addressT address; + symbolS *symbolP; + target = fragP->fr_offset; + address = fragP->fr_address; + symbolP = fragP->fr_symbol; + + if (symbolP) + { + fragS *sym_frag; + + sym_frag = symbol_get_frag (symbolP); + know (S_GET_SEGMENT (symbolP) != absolute_section + || sym_frag == &zero_address_frag); + target += S_GET_VALUE (symbolP); + + /* If frag has yet to be reached on this pass, assume it will + move by STRETCH just as we did. If this is not so, it will + be because some frag between grows, and that will force + another pass. */ + + if (stretch != 0 + && sym_frag->relax_marker != fragP->relax_marker + && S_GET_SEGMENT (symbolP) == seg) + target += stretch; + } + + aim = target - address - fragP->fr_fix; + if (aim >= PUSHJ_0B && aim <= PUSHJ_0F) + { + /* Target is reachable with a PUSHJ. */ + segment_info_type *seginfo = seg_info (seg); + + /* If we're at the end of a relaxation round, clear the stub + counter as initialization for the next round. */ + if (fragP == seginfo->tc_segment_info_data.last_stubfrag) + seginfo->tc_segment_info_data.nstubs = 0; + return 0; + } + + /* Not reachable. Try a stub. */ + fragP->fr_subtype = ENCODE_RELAX (STATE_PUSHJSTUB, STATE_ZERO); + } + /* FALLTHROUGH. */ + + /* See if this PUSHJ is redirectable to a stub. */ + case ENCODE_RELAX (STATE_PUSHJSTUB, STATE_ZERO): + { + segment_info_type *seginfo = seg_info (seg); + fragS *lastfrag = seginfo->frchainP->frch_last; + relax_substateT prev_type = fragP->fr_subtype; + + /* The last frag is always an empty frag, so it suffices to look + at its address to know the ending address of this section. */ + know (lastfrag->fr_type == rs_fill + && lastfrag->fr_fix == 0 + && lastfrag->fr_var == 0); + + /* For this PUSHJ to be relaxable into a call to a stub, the + distance must be no longer than 256k bytes from the PUSHJ to + the end of the section plus the maximum size of stubs so far. */ + if ((lastfrag->fr_address + + stretch + + PUSHJ_MAX_LEN * seginfo->tc_segment_info_data.nstubs) + - (fragP->fr_address + fragP->fr_fix) + > GETA_0F + || !pushj_stubs) + fragP->fr_subtype = mmix_relax_table[prev_type].rlx_more; + else + seginfo->tc_segment_info_data.nstubs++; + + /* If we're at the end of a relaxation round, clear the stub + counter as initialization for the next round. */ + if (fragP == seginfo->tc_segment_info_data.last_stubfrag) + seginfo->tc_segment_info_data.nstubs = 0; + + return + (mmix_relax_table[fragP->fr_subtype].rlx_length + - mmix_relax_table[prev_type].rlx_length); + } + + case ENCODE_RELAX (STATE_PUSHJ, STATE_MAX): + { + segment_info_type *seginfo = seg_info (seg); + + /* Need to cover all STATE_PUSHJ states to act on the last stub + frag (the end of this relax round; initialization for the + next). */ + if (fragP == seginfo->tc_segment_info_data.last_stubfrag) + seginfo->tc_segment_info_data.nstubs = 0; + + return 0; + } + + default: + return relax_frag (seg, fragP, stretch); + + case STATE_GREG_UNDF: + BAD_CASE (fragP->fr_subtype); + } as_fatal (_("internal: unexpected relax type %d:%d"), fragP->fr_type, fragP->fr_subtype); diff --git a/gas/config/tc-mmix.h b/gas/config/tc-mmix.h index 30d2c952a6..c6d222f1fd 100644 --- a/gas/config/tc-mmix.h +++ b/gas/config/tc-mmix.h @@ -1,5 +1,5 @@ /* tc-mmix.h -- Header file for tc-mmix.c. - Copyright (C) 2001, 2002 Free Software Foundation, Inc. + Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc. Written by Hans-Peter Nilsson (hp@bitrange.com). This file is part of GAS, the GNU Assembler. @@ -123,7 +123,7 @@ extern int mmix_assemble_return_nonzero PARAMS ((char *)); extern const struct relax_type mmix_relax_table[]; #define TC_GENERIC_RELAX_TABLE mmix_relax_table -/* We use the relax table for everything except the GREG frags. */ +/* We use the relax table for everything except the GREG frags and PUSHJ. */ extern long mmix_md_relax_frag PARAMS ((segT, fragS *, long)); #define md_relax_frag mmix_md_relax_frag @@ -199,6 +199,17 @@ extern void mmix_frob_file PARAMS ((void)); struct mmix_symbol_gregs; #define TC_SYMFIELD_TYPE struct mmix_symbol_gregs * +/* Used by relaxation, counting maximum needed PUSHJ stubs for a section. */ +struct mmix_segment_info_type + { + /* We only need to keep track of the last stubbable frag because + there's no less hackish way to keep track of different relaxation + rounds. */ + fragS *last_stubfrag; + bfd_size_type nstubs; + }; +#define TC_SEGMENT_INFO_TYPE struct mmix_segment_info_type + extern void mmix_md_elf_section_change_hook PARAMS ((void)); #define md_elf_section_change_hook mmix_md_elf_section_change_hook diff --git a/gas/doc/c-mmix.texi b/gas/doc/c-mmix.texi index d1b3016f41..a5205b61fc 100644 --- a/gas/doc/c-mmix.texi +++ b/gas/doc/c-mmix.texi @@ -82,6 +82,21 @@ that at link stage can be contracted. (Though linker relaxation isn't yet implemented in @code{@value{LD}}.) The option @samp{-x} also imples @samp{--linker-allocated-gregs}. +@cindex @samp{--no-pushj-stubs} command line option, MMIX +@cindex @samp{--no-stubs} command line option, MMIX +If instruction expansion is enabled, @code{@value{AS}} can expand a +@samp{PUSHJ} instruction into a series of instructions. The shortest +expansion is to not expand it, but just mark the call as redirectable to a +stub, which @code{@value{LD}} creates at link-time, but only if the +original @samp{PUSHJ} instruction is found not to reach the target. The +stub consists of the necessary instructions to form a jump to the target. +This happens if @code{@value{AS}} can assert that the @samp{PUSHJ} +instruction can reach such a stub. The option @samp{--no-pushj-stubs} +disables this shorter expansion, and the longer series of instructions is +then created at assembly-time. The option @samp{--no-stubs} is a synonym, +intended for compatibility with future releases, where generation of stubs +for other instructions may be implemented. + @cindex @samp{--linker-allocated-gregs} command line option, MMIX Usually a two-operand-expression (@pxref{GREG-base}) without a matching @samp{GREG} directive is treated as an error by @code{@value{AS}}. When -- 2.34.1