From 77592908ee412274452a954c5f0347bbc95497d3 Mon Sep 17 00:00:00 2001 From: Dmitry Diky Date: Fri, 12 Aug 2005 11:54:23 +0000 Subject: [PATCH] 2005-08-12 Dmitry Diky * config/tc-msp430.c (msp430_enable_relax): New flag. (msp430_enable_polys): Likewise. (OPTION_RELAX): New option. (OPTION_POLYMORPHS): Likewise. (md_longopts): New long options. (md_show_usage): Updated. (md_parse_option): Add new options handler. (msp430_operands): Add check if polymorph insns are enabled. (msp430_force_relocation_local): New function. (md_apply_fix): Now delete relocs according to new flags combination. (msp430_relax_frag): Convert long branches to short branches only if flag msp430_enable_relax is set. * config/tc-msp430.h (TC_FORCE_RELOCATION_LOCAL): Defined. (msp430_force_relocation_local): Likewise. * doc/c-msp430.texi: Describe new options. --- gas/ChangeLog | 17 +++++++ gas/config/tc-msp430.c | 113 ++++++++++++++++++++++++++++++++++++++--- gas/config/tc-msp430.h | 8 +++ gas/doc/c-msp430.texi | 15 ++++-- 4 files changed, 143 insertions(+), 10 deletions(-) diff --git a/gas/ChangeLog b/gas/ChangeLog index 1f5d8a0e3f9..bc98f76da43 100644 --- a/gas/ChangeLog +++ b/gas/ChangeLog @@ -1,3 +1,20 @@ +2005-08-12 Dmitry Diky + * config/tc-msp430.c (msp430_enable_relax): New flag. + (msp430_enable_polys): Likewise. + (OPTION_RELAX): New option. + (OPTION_POLYMORPHS): Likewise. + (md_longopts): New long options. + (md_show_usage): Updated. + (md_parse_option): Add new options handler. + (msp430_operands): Add check if polymorph insns are enabled. + (msp430_force_relocation_local): New function. + (md_apply_fix): Now delete relocs according to new flags combination. + (msp430_relax_frag): Convert long branches to short branches only if + flag msp430_enable_relax is set. + * config/tc-msp430.h (TC_FORCE_RELOCATION_LOCAL): Defined. + (msp430_force_relocation_local): Likewise. + * doc/c-msp430.texi: Describe new options. + 2005-08-11 Ian Lance Taylor * Makefile.am ($(srcdir)/make-gas.com): Remove target. diff --git a/gas/config/tc-msp430.c b/gas/config/tc-msp430.c index 5b6e196eb35..ed00c6978fb 100644 --- a/gas/config/tc-msp430.c +++ b/gas/config/tc-msp430.c @@ -31,6 +31,49 @@ #include "opcode/msp430.h" #include "safe-ctype.h" +/* + We will disable polymorphs by default because it is dangerous. + The potencial problem here is the following: assume we got the + following code: + + jump .l1 + nop + jump subroutine ; external symbol + .l1: + nop + ret + + In case of assembly time relaxation we'll get: + 0: jmp .l1 <.text +0x08> (reloc deleted) + 2: nop + 4: br subroutine + .l1: + 8: nop + 10: ret + + If the 'subroutine' wiys thin +-1024 bytes range then linker + will produce + 0: jmp .text +0x08 + 2: nop + 4: jmp subroutine + .l1: + 6: nop + 8: ret ; 'jmp .text +0x08' will land here. WRONG!!! + + + The workaround is the following: + 1. Declare global var enable_polymorphs which set to 1 via option -mP. + 2. Declare global var enable_relax which set to 1 via option -mQ. + + If polymorphs are enabled, and relax isn't, treat all jumps as long jumps, + do not delete any relocs and leave them for linker. + + If relax is enabled, relax at assembly time and kill relocs as necessary. + */ + +int msp430_enable_relax; +int msp430_enable_polys; + /* GCC uses the some condition codes which we'll implement as new polymorph instructions. @@ -660,6 +703,8 @@ extract_word (char * from, char * to, int limit) } #define OPTION_MMCU 'm' +#define OPTION_RELAX 'Q' +#define OPTION_POLYMORPHS 'P' static void msp430_set_arch (int dummy ATTRIBUTE_UNUSED) @@ -709,6 +754,17 @@ md_parse_option (int c, char * arg) as_fatal (_("redefinition of mcu type %s' to %s'"), msp430_mcu->name, mcu_types[i].name); return 1; + break; + + case OPTION_RELAX: + msp430_enable_relax = 1; + return 1; + break; + + case OPTION_POLYMORPHS: + msp430_enable_polys = 1; + return 1; + break; } return 0; @@ -727,6 +783,8 @@ const char *md_shortopts = "m:"; struct option md_longopts[] = { {"mmcu", required_argument, NULL, OPTION_MMCU}, + {"mP", no_argument, NULL, OPTION_POLYMORPHS}, + {"mQ", no_argument, NULL, OPTION_RELAX}, {NULL, no_argument, NULL, 0} }; @@ -758,6 +816,9 @@ md_show_usage (FILE * stream) " msp430xG437 msp430xG438 msp430G439\n" " msp430x435 msp430x436 msp430x437\n" " msp430x447 msp430x448 msp430x449\n")); + fprintf (stream, + _(" -mQ - enable relaxation at assembly time. DANGEROUS!\n" + " -mP - enable polymorph instructions\n")); show_mcu_list (stream); } @@ -1683,6 +1744,12 @@ msp430_operands (struct msp430_opcode_s * opcode, char * line) break; case 4: /* Extended jumps. */ + if (!msp430_enable_polys) + { + as_bad(_("polymorphs are not enabled. Use -mP option to enable.")); + break; + } + line = extract_operand (line, l1, sizeof (l1)); if (l1[0]) { @@ -1714,6 +1781,11 @@ msp430_operands (struct msp430_opcode_s * opcode, char * line) break; case 5: /* Emulated extended branches. */ + if (!msp430_enable_polys) + { + as_bad(_("polymorphs are not enabled. Use -mP option to enable.")); + break; + } line = extract_operand (line, l1, sizeof (l1)); if (l1[0]) { @@ -1820,9 +1892,24 @@ md_pcrel_from_section (fixS * fixp, segT sec) return fixp->fx_frag->fr_address + fixp->fx_where; } +/* Replaces standard TC_FORCE_RELOCATION_LOCAL. + Now it handles the situation when relocations + have to be passed to linker. */ +int +msp430_force_relocation_local(fixS *fixp) +{ + if (msp430_enable_polys + && !msp430_enable_relax) + return 1; + else + return (!fixp->fx_pcrel + || fixp->fx_plt + || generic_force_reloc(fixp)); +} + + /* GAS will call this for each fixup. It should store the correct value in the object file. */ - void md_apply_fix (fixS * fixp, valueT * valuep, segT seg) { @@ -1879,13 +1966,18 @@ md_apply_fix (fixS * fixp, valueT * valuep, segT seg) } } - switch (fixp->fx_r_type) + fixp->fx_no_overflow = 1; + + /* if polymorphs are enabled and relax disabled. + do not kill any relocs and pass them to linker. */ + if (msp430_enable_polys + && !msp430_enable_relax) { - default: - fixp->fx_no_overflow = 1; - break; - case BFD_RELOC_MSP430_10_PCREL: - break; + if (!fixp->fx_addsy || (fixp->fx_addsy + && S_GET_SEGMENT (fixp->fx_addsy) == absolute_section)) + fixp->fx_done = 1; /* it is ok to kill 'abs' reloc */ + else + fixp->fx_done = 0; } if (fixp->fx_done) @@ -2185,6 +2277,13 @@ msp430_relax_frag (segT seg ATTRIBUTE_UNUSED, fragS * fragP, aim = S_GET_VALUE (symbolP) - fragP->fr_address - fragP->fr_fix; } + if (!msp430_enable_relax) + { + /* Relaxation is not enabled. So, make all jump as long ones + by setting 'aim' to quite high value. */ + aim = 0x7fff; + } + this_state = fragP->fr_subtype; start_type = this_type = table + this_state; diff --git a/gas/config/tc-msp430.h b/gas/config/tc-msp430.h index 632e2a923b5..9fef126e551 100644 --- a/gas/config/tc-msp430.h +++ b/gas/config/tc-msp430.h @@ -112,3 +112,11 @@ extern long md_pcrel_from_section (struct fix *, segT); #define md_relax_frag(SEG, FRAGP, STRETCH) \ msp430_relax_frag (SEG, FRAGP, STRETCH) extern long msp430_relax_frag (segT, fragS *, long); + +#define TC_FORCE_RELOCATION_LOCAL(FIX) \ + msp430_force_relocation_local(FIX) +extern int msp430_force_relocation_local(struct fix *); + + +extern int msp430_enable_relax; +extern int msp430_enable_polys; diff --git a/gas/doc/c-msp430.texi b/gas/doc/c-msp430.texi index b3989522809..33f3e83ffbc 100644 --- a/gas/doc/c-msp430.texi +++ b/gas/doc/c-msp430.texi @@ -26,8 +26,17 @@ @section Options @cindex MSP 430 options (none) @cindex options for MSP430 (none) -@code{@value{AS}} has only -m flag which selects the mpu arch. Currently has -no effect. +@table @code + +@item -m +select the mpu arch. Currently has no effect. +@item -mP +enables polymorph instructions handler. + +@item -mQ +enables relaxation at assembly time. DANGEROUS! + +@end table @node MSP430 Syntax @section Syntax @@ -214,7 +223,7 @@ This directive instructs assembler to add new profile entry to the object file. additional pseudo-instructions are needed on this family. For information on the 430 machine instruction set, see @cite{MSP430 -User's Manual, document slau049b}, Texas Instrument, Inc. +User's Manual, document slau049d}, Texas Instrument, Inc. @node MSP430 Profiling Capability @section Profiling Capability -- 2.30.2