Message ID | 20170613134951.29359-1-Anton.Kolesov@synopsys.com |
---|---|
State | New, archived |
Headers |
Received: (qmail 130298 invoked by alias); 13 Jun 2017 13:49:56 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: <gdb-patches.sourceware.org> List-Unsubscribe: <mailto:gdb-patches-unsubscribe-##L=##H@sourceware.org> List-Subscribe: <mailto:gdb-patches-subscribe@sourceware.org> List-Archive: <http://sourceware.org/ml/gdb-patches/> List-Post: <mailto:gdb-patches@sourceware.org> List-Help: <mailto:gdb-patches-help@sourceware.org>, <http://sourceware.org/ml/#faqs> Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 129411 invoked by uid 89); 13 Jun 2017 13:49:55 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-23.7 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_LAZY_DOMAIN_SECURITY, RCVD_IN_DNSWL_NONE, T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 spammy=HX-HELO:sk:smtprel, anton, Anton, H*r:sk:mailhos X-HELO: smtprelay.synopsys.com Received: from smtprelay4.synopsys.com (HELO smtprelay.synopsys.com) (198.182.47.9) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 13 Jun 2017 13:49:53 +0000 Received: from mailhost.synopsys.com (mailhost2.synopsys.com [10.13.184.66]) by smtprelay.synopsys.com (Postfix) with ESMTP id 0BEF024E1263 for <gdb-patches@sourceware.org>; Tue, 13 Jun 2017 06:49:57 -0700 (PDT) Received: from mailhost.synopsys.com (localhost [127.0.0.1]) by mailhost.synopsys.com (Postfix) with ESMTP id EBF7867C; Tue, 13 Jun 2017 06:49:56 -0700 (PDT) Received: from akolesov-lab.internal.synopsys.com (akolesov-lab.internal.synopsys.com [10.121.14.106]) by mailhost.synopsys.com (Postfix) with ESMTP id E880A66E; Tue, 13 Jun 2017 06:49:55 -0700 (PDT) From: Anton Kolesov <Anton.Kolesov@synopsys.com> To: gdb-patches@sourceware.org Cc: Anton Kolesov <Anton.Kolesov@synopsys.com>, Francois Bedard <Francois.Bedard@synopsys.com> Subject: [PATCH v2] arc: Select CPU model properly before disassembling Date: Tue, 13 Jun 2017 16:49:51 +0300 Message-Id: <20170613134951.29359-1-Anton.Kolesov@synopsys.com> In-Reply-To: <39A54937CC95F24AA2F794E2D2B66B135874F238@DE02WEMBXB.internal.synopsys.com> References: <39A54937CC95F24AA2F794E2D2B66B135874F238@DE02WEMBXB.internal.synopsys.com> |
Commit Message
Anton Kolesov
June 13, 2017, 1:49 p.m. UTC
Changes in V2: * Use xstrprintf instead of string_printf * Reinstate arc_delayed_print_insn as a print instruction function for ARC. * Change arc_delayed_print_insn to use default_print_insn. * Change commit description accordingly. --- Enforce CPU model for disassembler via its options, if it was specified in XML target description, otherwise use default method of determining CPU implemented in disassembler - scanning ELF private header. The latter requires disassemble_info->section to be properly initialized. To make sure that info->section is set in all cases this patch partially reverts [1] for ARC: it reinstates arc_delayed_print_insn as a "print_insn" function for ARC, but now this function only sets disassemble_info->section and then calls default_print_insn to do the rest of the job. Support for CPU in disassembler options for ARC has been added in [2]. [1] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=39503f82427e22ed8e04d986ccdc8562091ec62e [2] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=10045478d984f9924cb945423388ba25b7dd3ffe gdb/ChangeLog: yyyy-mm-dd Anton Kolesov <anton.kolesov@synopsys.com> * arc-tdep.c (arc_disassembler_options): New variable. (arc_gdbarch_init): Set and use it. Use arc_delayed_print_insn instead of default_print_insn. (arc_delayed_print_insn): Set info->section when needed, use default_print_insn to retrieve a disassembler. --- gdb/arc-tdep.c | 51 +++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 45 insertions(+), 6 deletions(-)
Comments
On 2017-06-13 15:49, Anton Kolesov wrote: > Changes in V2: > > * Use xstrprintf instead of string_printf > * Reinstate arc_delayed_print_insn as a print instruction function for > ARC. > * Change arc_delayed_print_insn to use default_print_insn. > * Change commit description accordingly. > > --- > > Enforce CPU model for disassembler via its options, if it was specified > in XML > target description, otherwise use default method of determining CPU > implemented > in disassembler - scanning ELF private header. The latter requires > disassemble_info->section to be properly initialized. To make sure > that > info->section is set in all cases this patch partially reverts [1] for > ARC: it > reinstates arc_delayed_print_insn as a "print_insn" function for ARC, > but > now this function only sets disassemble_info->section and then calls > default_print_insn to do the rest of the job. > > Support for CPU in disassembler options for ARC has been added in [2]. The patch looks good to me, there's just one formatting nit below, and some random thoughts (which doesn't affect the fact that the patch LGTM). > [1] > https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=39503f82427e22ed8e04d986ccdc8562091ec62e > [2] > https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=10045478d984f9924cb945423388ba25b7dd3ffe > > gdb/ChangeLog: > > yyyy-mm-dd Anton Kolesov <anton.kolesov@synopsys.com> > > * arc-tdep.c (arc_disassembler_options): New variable. > (arc_gdbarch_init): Set and use it. Use arc_delayed_print_insn instead > of default_print_insn. > (arc_delayed_print_insn): Set info->section when needed, > use default_print_insn to retrieve a disassembler. > --- > gdb/arc-tdep.c | 51 > +++++++++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 45 insertions(+), 6 deletions(-) > > diff --git a/gdb/arc-tdep.c b/gdb/arc-tdep.c > index d9ee5c6..9a5efc1 100644 > --- a/gdb/arc-tdep.c > +++ b/gdb/arc-tdep.c > @@ -145,6 +145,8 @@ static const char *const > core_arcompact_register_names[] = { > "lp_count", "reserved", "limm", "pcl", > }; > > +static char *arc_disassembler_options = NULL; > + > /* Functions are sorted in the order as they are used in the > _initialize_arc_tdep (), which uses the same order as gdbarch.h. > Static > functions are defined before the first invocation. */ > @@ -1405,12 +1407,31 @@ arc_skip_prologue (struct gdbarch *gdbarch, > CORE_ADDR pc) > int > arc_delayed_print_insn (bfd_vma addr, struct disassemble_info *info) > { > - int (*print_insn) (bfd_vma, struct disassemble_info *); > - /* exec_bfd may be null, if GDB is run without a target BFD file. > Opcodes > - will handle NULL value gracefully. */ > - print_insn = arc_get_disassembler (exec_bfd); > - gdb_assert (print_insn != NULL); > - return print_insn (addr, info); > + /* Standard BFD "machine number" field allows libocodes disassembler > to > + distinguish ARC 600, 700 and v2 cores, however v2 encompasses > both ARC EM > + and HS, which have some difference between. There are two ways > to specify > + what is the target core: > + 1) via the disassemble_info->disassembler_options; > + 2) otherwise libopcodes will use private (architecture-specific) > ELF > + header. > + > + Using disassembler_options is preferable, because it comes > directly from > + GDBserver which scanned an actual ARC core identification info. > However, > + not all GDBservers report core architecture, so as a fallback GDB > still > + should support analysis of ELF header. The libopcodes > disassembly code > + uses the section to find the BFD and the BFD to find the ELF > header, > + therefore this function should set disassemble_info->section > properly. > + > + disassembler_options was already set by non-target specific code > with > + proper options obtained via gdbarch_disassembler_options (). */ > + if (info->disassembler_options == NULL) > + { > + struct obj_section * s = find_pc_section (addr); Extra space after the *. > + if (s != NULL) > + info->section = s->the_bfd_section; > + } When printing multiple instructions in a row, is this function called multiple times with the same disassemble_info? If so, are we going to make a find_pc_section call for each instruction? Is this needed, given that the options won't change for a given ELF (on ARC at least)? > + > + return default_print_insn (addr, info); > } > > /* Baremetal breakpoint instructions. > @@ -2013,6 +2034,8 @@ arc_gdbarch_init (struct gdbarch_info info, > struct gdbarch_list *arches) > > set_gdbarch_frame_align (gdbarch, arc_frame_align); > > + set_gdbarch_print_insn (gdbarch, arc_delayed_print_insn); > + > set_gdbarch_cannot_step_breakpoint (gdbarch, 1); > > /* "nonsteppable" watchpoint means that watchpoint triggers before > @@ -2041,6 +2064,22 @@ arc_gdbarch_init (struct gdbarch_info info, > struct gdbarch_list *arches) > if (tdep->jb_pc >= 0) > set_gdbarch_get_longjmp_target (gdbarch, arc_get_longjmp_target); > > + /* Disassembler options. Enforce CPU if it was specified in XML > target > + description, otherwise use default method of determining CPU (ELF > private > + header). */ > + if (info.target_desc != NULL) > + { > + const struct bfd_arch_info *tdesc_arch > + = tdesc_architecture (info.target_desc); > + if (tdesc_arch != NULL) > + { > + arc_disassembler_options = xstrprintf ("cpu=%s", > + tdesc_arch->printable_name); > + set_gdbarch_disassembler_options (gdbarch, > + &arc_disassembler_options); > + } > + } > + I was a bit concerned with the fact that multiple gdbarch objects (that represent different architectures) can end up sharing the same pointer to arc_disassembler_options, so necessarily some of them will have the wrong value at a certain point. But that doesn't look like an immediate problem, since you don't seem to recycle previously created gdbarch objects, like some other architectures do (does that mean that the gdbarch list keeps growing indefinitely if you connect multiple times, load new exec files?). The gdbarch in use should always be the last that was created, so arc_disassembler_options should contain the good value for that gdbarch. I was thinking that a situation like this could be problematic, if you were re-using gdbarch objects: 1. You connect to a gdbserver that reports arch A. A gdbarch is created and arc_disassembler_options is set for arch A. 2. You disconnect, and connect to a gdbserver that reports arch B. A gdbarch is created and arc_disassembler_options is set for arch B. 3. You disconnect, and connect again to the first gdbserver. This time, you would return the existing gdbarch for arch A, so the current gdbarch (arch A) would still use the disassembler options of arch B. But like I said, that doesn't seem to be the case right now. That makes me wonder why we pass a char ** and not simply an allocated char *, of which the gdbarch would take ownership, which would avoid this problem entirely. Simon
Hi Simon, > > + if (info->disassembler_options == NULL) > > + { > > + struct obj_section * s = find_pc_section (addr); > > Extra space after the *. This was copied from mep-tdep.c. Should I make a separate patch that fixes it there too? > > > + if (s != NULL) > > + info->section = s->the_bfd_section; > > + } > > When printing multiple instructions in a row, is this function called multiple > times with the same disassemble_info? If so, are we going to make a > find_pc_section call for each instruction? Is this needed, given that the > options won't change for a given ELF (on ARC at least)? I think it might not work if there is a multi-arch target and disassembler invocation tries to dump instructions across multiple sections which come from different ELF files (not sure if shared libraries would count as a separate ELF files). But usually disassembler works per-function and practically I don't think that there would be a case of function that crosses section boundary. I've put this optimization to my v3 patch. > > I was a bit concerned with the fact that multiple gdbarch objects (that > represent different architectures) can end up sharing the same pointer to > arc_disassembler_options, so necessarily some of them will have the wrong > value at a certain point. But that doesn't look like an immediate problem, > since you don't seem to recycle previously created gdbarch objects, like > some other architectures do (does that mean that the gdbarch list keeps > growing indefinitely if you connect multiple times, load new exec files?). The > gdbarch in use should always be the last that was created, so > arc_disassembler_options should contain the good value for that gdbarch. I > was thinking that a situation like this could be problematic, if you were re- > using gdbarch objects: > > 1. You connect to a gdbserver that reports arch A. A gdbarch is created and > arc_disassembler_options is set for arch A. > 2. You disconnect, and connect to a gdbserver that reports arch B. A gdbarch > is created and arc_disassembler_options is set for arch B. > 3. You disconnect, and connect again to the first gdbserver. This time, you > would return the existing gdbarch for arch A, so the current gdbarch (arch A) > would still use the disassembler options of arch B. > > But like I said, that doesn't seem to be the case right now. > > That makes me wonder why we pass a char ** and not simply an allocated > char *, of which the gdbarch would take ownership, which would avoid this > problem entirely. This is the same thing as in {arm,rs6000,s390-linux}-tdep.c - they all use global static variable, which would be shared across multiple gdbarch instances. So when options are changed that would change that for any gdbarch of that architecture. RS6000 and S390 don't even assign this variable any value - it completely managed by the disasm.c. Although in ARC case there is a memory leak, because arc_disassembler_options is only assigned by arc-tdep.c and never freed - that's because I didn't properly understood what other arches do - they don't free options as well, but they also don't allocate them in each gdbarch_init, because there usecase is somewhat different. I'm not sure how big of a problem this leak is, because outside of a GDB test suite I don't think there are a lot of practical cases where same GDB instance is reused to connect/disconnect, so leak wouldn't be noticeable. I think, I can make things better for ARC, by moving arc_disassembler_options into the gdbarch_tdep, then each gdbarch for ARC will have its own options, but that would mean behavior different from other arches which support disassembler_options - there options are shared across gdbarches of architecture. Should I do that in V3? TBH, that would be a moot for ARC right now, because today our disassembler has a global state and it doesn't support simultaneous disassembly of different ARC architectures anyway, but it might make sense to try to make sure that GDB part handles this correctly, if in the future disassembler would be upgraded to avoid global state. The reuse of gdbarch instances seems like a good idea, will try to add that in the future for ARC. Anton > > Simon
On 2017-06-14 16:02, Anton Kolesov wrote: > This is the same thing as in {arm,rs6000,s390-linux}-tdep.c - they all > use > global static variable, which would be shared across multiple gdbarch > instances. So when options are changed that would change that for any > gdbarch > of that architecture. RS6000 and S390 don't even assign this variable > any value > - it completely managed by the disasm.c. Although in ARC case there is > a memory > leak, because arc_disassembler_options is only assigned by arc-tdep.c > and > never freed - that's because I didn't properly understood what other > arches > do - they don't free options as well, but they also don't allocate them > in > each gdbarch_init, because there usecase is somewhat different. Indeed, set_disassembler_options takes care of the allocation/deallocation when the user changes the options. > I'm not sure > how big of a problem this leak is, because outside of a GDB test suite > I don't > think there are a lot of practical cases where same GDB instance is > reused to > connect/disconnect, so leak wouldn't be noticeable. I think, I can make > things better for ARC, by moving arc_disassembler_options into the > gdbarch_tdep, then each gdbarch for ARC will have its own options, but > that > would mean behavior different from other arches which support > disassembler_options - there options are shared across gdbarches of > architecture. Should I do that in V3? Ah, I did not understand previously that sharing the disassembler options between all gdbarches of an architecture is the intended behavior. Having different behavior across architectures for this wouldn't be a good idea, I think. Also, as of today, the disassembler options are very much user driven. The architecture family can set some default at startup (ARM, for example, sets "reg-names-std"), but after that it's all up to the user. In your case, it's the opposite along those two axis: you want GDB to set disassembler options in the back of the user, and you want disassembler options (at least some of them) to be gdbarch-specific. To support that correctly, I think we should first define what behavior we want from GDB. For example: - if the user doesn't specify any disassembler-options, it's probably right to automatically set it for them. - if the user provides a disassembler option other than cpu= and then connects to a gdbserver, we probably want to add the cpu= to what they have specified. - if they connect first and then set another, unrelated option, do we keep the cpu= option or does it get lost? - if they set a particular cpu= option and then connect to a gdbserver that reports something else, which one do we choose? - if they connect to a gdbserver that reports an architecture and we add a cpu= for it, then they connect to a gdbserver that doesn't report an architecture, do we keep the previous cpu= or not? - what happens with the various options when we switch gdbarch, do we keep the user-provided ones but flush the GDB-inferred ones? Once we know what behavior we want from GDB, I think it will be easier to decide what to put where. In the mean time, if you think the current patch makes the situation better for ARC users in the typical usage scenarios, I'm fine with going with it. Note that there will be a change for your users: connecting to a target will overwrite whatever option they might have set before connecting. Also, to avoid the leak, you could xfree the previous arc_disassembler_options before assigning it in arc_gdbarch_init. > TBH, that would be a moot for ARC right now, because today our > disassembler > has a global state and it doesn't support simultaneous disassembly of > different ARC architectures anyway, but it might make sense to try to > make > sure that GDB part handles this correctly, if in the future > disassembler > would be upgraded to avoid global state. > > The reuse of gdbarch instances seems like a good idea, will try to add > that > in the future for ARC. > > Anton Thanks, Simon
On 06/14/2017 05:27 PM, Simon Marchi wrote: > On 2017-06-14 16:02, Anton Kolesov wrote: >> This is the same thing as in {arm,rs6000,s390-linux}-tdep.c - they all >> use >> global static variable, which would be shared across multiple gdbarch >> instances. So when options are changed that would change that for any >> gdbarch >> of that architecture. RS6000 and S390 don't even assign this variable >> any value >> - it completely managed by the disasm.c. Although in ARC case there is >> a memory >> leak, because arc_disassembler_options is only assigned by arc-tdep.c and >> never freed - that's because I didn't properly understood what other >> arches >> do - they don't free options as well, but they also don't allocate >> them in >> each gdbarch_init, because there usecase is somewhat different. > > Indeed, set_disassembler_options takes care of the > allocation/deallocation when the user changes the options. > >> I'm not sure >> how big of a problem this leak is, because outside of a GDB test suite >> I don't >> think there are a lot of practical cases where same GDB instance is >> reused to >> connect/disconnect, so leak wouldn't be noticeable. I think, I can make >> things better for ARC, by moving arc_disassembler_options into the >> gdbarch_tdep, then each gdbarch for ARC will have its own options, but >> that >> would mean behavior different from other arches which support >> disassembler_options - there options are shared across gdbarches of >> architecture. Should I do that in V3? > > Ah, I did not understand previously that sharing the disassembler > options between all gdbarches of an architecture is the intended > behavior. Having different behavior across architectures for this > wouldn't be a good idea, I think. Also, as of today, the disassembler > options are very much user driven. The architecture family can set some > default at startup (ARM, for example, sets "reg-names-std"), but after > that it's all up to the user. Right, in a given debug session you can have different gdbarch instances at play even for the same cpu architecture. E.g., the gdbarch determined for the binary vs the gdbarch created for the target description. > > In your case, it's the opposite along those two axis: you want GDB to > set disassembler options in the back of the user, and you want > disassembler options (at least some of them) to be gdbarch-specific. To > support that correctly, I think we should first define what behavior we > want from GDB. For example: > > - if the user doesn't specify any disassembler-options, it's probably > right to automatically set it for them. > - if the user provides a disassembler option other than cpu= and then > connects to a gdbserver, we probably want to add the cpu= to what they > have specified. > - if they connect first and then set another, unrelated option, do we > keep the cpu= option or does it get lost? > - if they set a particular cpu= option and then connect to a gdbserver > that reports something else, which one do we choose? > - if they connect to a gdbserver that reports an architecture and we > add a cpu= for it, then they connect to a gdbserver that doesn't report > an architecture, do we keep the previous cpu= or not? > - what happens with the various options when we switch gdbarch, do we > keep the user-provided ones but flush the GDB-inferred ones? I'd think that the "set/show disassembler-options" setting wouldn't ever be changed by connecting to a target and that whatever the user explicitly set should be respected. I.e., gdb / opcodes would choose which cpu to use for disassembly based on this logical sequence: - if user specified cpu, use that, - otherwise, if tdesc specified cpu, use that, - otherwise, infer cpu from bfd/elf section, - otherwise, use default cpu Thanks, Pedro Alves
> > I'd think that the "set/show disassembler-options" setting wouldn't ever be > changed by connecting to a target and that whatever the user explicitly set > should be respected. > > I.e., gdb / opcodes would choose which cpu to use for disassembly based on > this logical sequence: > > - if user specified cpu, use that, > - otherwise, if tdesc specified cpu, use that, > - otherwise, infer cpu from bfd/elf section, > - otherwise, use default cpu However for ARC we don't support "set disassembler-options", because this option requires valid disassembler_options to be provided, and arc-tdep.c doesn't do this - so currently "set disassembler-options ..." reports as unsupported. I agree that in general this option that comes from XML description probably should be hidden from the user and not shown via "show disassembler-options". One possible way is that CPU from target description will be stored in the ARC gdbarch_tdep, and then will be appended to disassemble_info options in the arc_delayed_print_insn if cpu= hasn't been specified by the user. As far as I can see this situation is pretty specific to ARC, because we have two bfd_arch_info instances sharing the same machine number (to be compatible with our proprietary toolchain), so <architecture> tag in XML description doesn't work the way it should - it selects the first of those two architectures in the internal BFD list, regardless of which one was actually in the description. Anton > > Thanks, > Pedro Alves
diff --git a/gdb/arc-tdep.c b/gdb/arc-tdep.c index d9ee5c6..9a5efc1 100644 --- a/gdb/arc-tdep.c +++ b/gdb/arc-tdep.c @@ -145,6 +145,8 @@ static const char *const core_arcompact_register_names[] = { "lp_count", "reserved", "limm", "pcl", }; +static char *arc_disassembler_options = NULL; + /* Functions are sorted in the order as they are used in the _initialize_arc_tdep (), which uses the same order as gdbarch.h. Static functions are defined before the first invocation. */ @@ -1405,12 +1407,31 @@ arc_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc) int arc_delayed_print_insn (bfd_vma addr, struct disassemble_info *info) { - int (*print_insn) (bfd_vma, struct disassemble_info *); - /* exec_bfd may be null, if GDB is run without a target BFD file. Opcodes - will handle NULL value gracefully. */ - print_insn = arc_get_disassembler (exec_bfd); - gdb_assert (print_insn != NULL); - return print_insn (addr, info); + /* Standard BFD "machine number" field allows libocodes disassembler to + distinguish ARC 600, 700 and v2 cores, however v2 encompasses both ARC EM + and HS, which have some difference between. There are two ways to specify + what is the target core: + 1) via the disassemble_info->disassembler_options; + 2) otherwise libopcodes will use private (architecture-specific) ELF + header. + + Using disassembler_options is preferable, because it comes directly from + GDBserver which scanned an actual ARC core identification info. However, + not all GDBservers report core architecture, so as a fallback GDB still + should support analysis of ELF header. The libopcodes disassembly code + uses the section to find the BFD and the BFD to find the ELF header, + therefore this function should set disassemble_info->section properly. + + disassembler_options was already set by non-target specific code with + proper options obtained via gdbarch_disassembler_options (). */ + if (info->disassembler_options == NULL) + { + struct obj_section * s = find_pc_section (addr); + if (s != NULL) + info->section = s->the_bfd_section; + } + + return default_print_insn (addr, info); } /* Baremetal breakpoint instructions. @@ -2013,6 +2034,8 @@ arc_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) set_gdbarch_frame_align (gdbarch, arc_frame_align); + set_gdbarch_print_insn (gdbarch, arc_delayed_print_insn); + set_gdbarch_cannot_step_breakpoint (gdbarch, 1); /* "nonsteppable" watchpoint means that watchpoint triggers before @@ -2041,6 +2064,22 @@ arc_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) if (tdep->jb_pc >= 0) set_gdbarch_get_longjmp_target (gdbarch, arc_get_longjmp_target); + /* Disassembler options. Enforce CPU if it was specified in XML target + description, otherwise use default method of determining CPU (ELF private + header). */ + if (info.target_desc != NULL) + { + const struct bfd_arch_info *tdesc_arch + = tdesc_architecture (info.target_desc); + if (tdesc_arch != NULL) + { + arc_disassembler_options = xstrprintf ("cpu=%s", + tdesc_arch->printable_name); + set_gdbarch_disassembler_options (gdbarch, + &arc_disassembler_options); + } + } + tdesc_use_registers (gdbarch, tdesc, tdesc_data); return gdbarch;