| Message ID | 56186808-25DF-4EB9-AED6-3EDF309FEAA6@sandoe-acoustics.co.uk |
|---|---|
| State | New |
| Headers | show |
On 12/20/2010 03:18 AM, IainS wrote: > + /* There is no real support in DW2 for this .. so we make > + a work-around. First, emit the pub name for the segment > + containing the function label. Then make and emit a > + simplified subprogram DIE for the second segment with the > + name post-fixed with _$hot$ or _$cold$. We use the same > + linkage name for the second die so that gdb will find both > + sections when given "b foo". */ This doesn't work when $ is not allowed, aka NO_DOLLAR_IN_LABEL. Presumably we need this workaround since Darwin is strict dwarf2? r~
On 20 Dec 2010, at 21:15, Richard Henderson wrote: > On 12/20/2010 03:18 AM, IainS wrote: >> + /* There is no real support in DW2 for this .. so we make >> + a work-around. First, emit the pub name for the segment >> + containing the function label. Then make and emit a >> + simplified subprogram DIE for the second segment with the >> + name post-fixed with _$hot$ or _$cold$. We use the same >> + linkage name for the second die so that gdb will find both >> + sections when given "b foo". */ > > This doesn't work when $ is not allowed, aka NO_DOLLAR_IN_LABEL. > Presumably we need this workaround since Darwin is strict dwarf2? Yes, we need the work-around .. but I'm not massively attached to $ (or even £ ;-)) is it OK apart from that? cheers Iain
On 12/20/2010 01:20 PM, IainS wrote: > > On 20 Dec 2010, at 21:15, Richard Henderson wrote: > >> On 12/20/2010 03:18 AM, IainS wrote: >>> + /* There is no real support in DW2 for this .. so we make >>> + a work-around. First, emit the pub name for the segment >>> + containing the function label. Then make and emit a >>> + simplified subprogram DIE for the second segment with the >>> + name post-fixed with _$hot$ or _$cold$. We use the same >>> + linkage name for the second die so that gdb will find both >>> + sections when given "b foo". */ >> >> This doesn't work when $ is not allowed, aka NO_DOLLAR_IN_LABEL. >> Presumably we need this workaround since Darwin is strict dwarf2? > > Yes, we need the work-around .. > but I'm not massively attached to $ (or even £ ;-)) > > is it OK apart from that? Yeah, and I suppose you're after matching the symbols here with the symbols from that previous patch. Ok with an extra bit akin to the use in clone_function_name: #ifndef NO_DOT_IN_LABEL prefix[len] = '.'; #elif !defined NO_DOLLAR_IN_LABEL prefix[len] = '$'; #else prefix[len] = '_'; #endif though of course you may swap the preferencing of [$.] to match what you already have in darwin.c. r~
On 20 Dec 2010, at 21:38, Richard Henderson wrote: > On 12/20/2010 01:20 PM, IainS wrote: >> >> On 20 Dec 2010, at 21:15, Richard Henderson wrote: >> >>> On 12/20/2010 03:18 AM, IainS wrote: >>>> + /* There is no real support in DW2 for this .. so we >>>> make >>>> + a work-around. First, emit the pub name for the >>>> segment >>>> + containing the function label. Then make and emit a >>>> + simplified subprogram DIE for the second segment >>>> with the >>>> + name post-fixed with _$hot$ or _$cold$. We use the >>>> same >>>> + linkage name for the second die so that gdb will >>>> find both >>>> + sections when given "b foo". */ >>> >>> This doesn't work when $ is not allowed, aka NO_DOLLAR_IN_LABEL. >>> Presumably we need this workaround since Darwin is strict dwarf2? >> >> Yes, we need the work-around .. FWIW, the problem is that we support only a sub-set of DW3 - so if you try gcc -gdwarf-3 either the linker or dsymutil dies. so, we're stuck with DW2/strict. >> but I'm not massively attached to $ (or even £ ;-)) >> >> is it OK apart from that? > > Yeah, and I suppose you're after matching the symbols here with > the symbols from that previous patch. > > Ok with an extra bit akin to the use in clone_function_name: > > #ifndef NO_DOT_IN_LABEL > prefix[len] = '.'; > #elif !defined NO_DOLLAR_IN_LABEL > prefix[len] = '$'; > #else > prefix[len] = '_'; > #endif > > though of course you may swap the preferencing of [$.] to match > what you already have in darwin.c. what I'm after is (a) avoiding a name clash. (b) having a generated tag which is clearly understandable to the person debugging .. If I prefix (rather than the current post-fix) with "__hot_" and "__cold_" (or even __hot_partition_) that should be safe and not require the extra hoops? (I"m happy to do what you've suggested above, of course, if that's the best solution). thanks, Iain
On 12/20/2010 01:49 PM, IainS wrote: > what I'm after is > (a) avoiding a name clash. > (b) having a generated tag which is clearly understandable to the person debugging .. > > If I prefix (rather than the current post-fix) with "__hot_" and > "__cold_" (or even __hot_partition_) that should be safe and not > require the extra hoops? Yes, that should work. I do question whether you want this symbol to match up with the name generated in the "atom" patch though. r~
On 20 Dec 2010, at 22:06, Richard Henderson wrote: > On 12/20/2010 01:49 PM, IainS wrote: >> what I'm after is >> (a) avoiding a name clash. >> (b) having a generated tag which is clearly understandable to the >> person debugging .. >> >> If I prefix (rather than the current post-fix) with "__hot_" and >> "__cold_" (or even __hot_partition_) that should be safe and not >> require the extra hoops? > > Yes, that should work. I do question whether you want this symbol > to match up with the name generated in the "atom" patch though. Yes, I think that is a good idea - I will amend the other patch to match this one, assuming Mike also OKs it, thanks, for your reviews, Iain
On 20 Dec 2010, at 22:43, IainS wrote: > > On 20 Dec 2010, at 22:06, Richard Henderson wrote: > >> On 12/20/2010 01:49 PM, IainS wrote: >>> what I'm after is >>> (a) avoiding a name clash. >>> (b) having a generated tag which is clearly understandable to the >>> person debugging .. >>> >>> If I prefix (rather than the current post-fix) with "__hot_" and >>> "__cold_" (or even __hot_partition_) that should be safe and not >>> require the extra hoops? >> >> Yes, that should work. I do question whether you want this symbol >> to match up with the name generated in the "atom" patch though. > > > Yes, I think that is a good idea - I will amend the other patch to > match this one, assuming Mike also OKs it, > thanks, for your reviews, I've now amended the darwf2 patch thus: /* There is no real support in DW2 for this .. so we make a work-around. First, emit the pub name for the segment containing the function label. Then make and emit a simplified subprogram DIE for the second segment with the name pre-fixed by __hot/cold_sect_of_. We use the same linkage name for the second die so that gdb will find both sections when given "b foo". */ <snip> if (fde->in_std_section) { name = concat ("__cold_sect_of_", name, NULL); etc. and the config/darwin.c patch to match this. FAOD, are the two patches now OK to apply, assuming Mike is happy with the Darwin aspects? thanks Iain
On 12/21/2010 04:45 AM, IainS wrote:
> name = concat ("__cold_sect_of_", name, NULL);
Yes, this is fine.
r~
On Dec 20, 2010, at 3:18 AM, IainS <developer@sandoe-acoustics.co.uk> wrote: > At present, pubnames are not emitted when -freorder-blocks-and-partition is active. Ok with the change to not use . or $ in the label. >
Index: gcc/dwarf2out.c =================================================================== --- gcc/dwarf2out.c (revision 168084) +++ gcc/dwarf2out.c (working copy) @@ -18897,7 +18897,6 @@ static void gen_subprogram_die (tree decl, dw_die_ref context_die) { - char label_id[MAX_ARTIFICIAL_LABEL_BYTES]; tree origin = decl_ultimate_origin (decl); dw_die_ref subr_die; tree fn_arg_types; @@ -19067,12 +19066,24 @@ if (!flag_reorder_blocks_and_partition) { - ASM_GENERATE_INTERNAL_LABEL (label_id, FUNC_BEGIN_LABEL, - current_function_funcdef_no); - add_AT_lbl_id (subr_die, DW_AT_low_pc, label_id); - ASM_GENERATE_INTERNAL_LABEL (label_id, FUNC_END_LABEL, - current_function_funcdef_no); - add_AT_lbl_id (subr_die, DW_AT_high_pc, label_id); + dw_fde_ref fde = &fde_table[current_funcdef_fde]; + if (fde->dw_fde_begin) + { + /* We have already generated the labels. */ + add_AT_lbl_id (subr_die, DW_AT_low_pc, fde->dw_fde_begin); + add_AT_lbl_id (subr_die, DW_AT_high_pc, fde->dw_fde_end); + } + else + { + /* Create start/end labels and add the range. */ + char label_id[MAX_ARTIFICIAL_LABEL_BYTES]; + ASM_GENERATE_INTERNAL_LABEL (label_id, FUNC_BEGIN_LABEL, + current_function_funcdef_no); + add_AT_lbl_id (subr_die, DW_AT_low_pc, label_id); + ASM_GENERATE_INTERNAL_LABEL (label_id, FUNC_END_LABEL, + current_function_funcdef_no); + add_AT_lbl_id (subr_die, DW_AT_high_pc, label_id); + } #if VMS_DEBUGGING_INFO /* HP OpenVMS Industry Standard 64: DWARF Extensions @@ -19088,8 +19099,6 @@ attributes allow a compiler to communicate the location(s) to use. */ { - dw_fde_ref fde = &fde_table[current_funcdef_fde]; - if (fde->dw_fde_vms_end_prologue) add_AT_vms_delta (subr_die, DW_AT_HP_prologue, fde->dw_fde_begin, fde->dw_fde_vms_end_prologue); @@ -19104,19 +19113,116 @@ add_arange (decl, subr_die); } else - { /* Do nothing for now; maybe need to duplicate die, one for - hot section and one for cold section, then use the hot/cold - section begin/end labels to generate the aranges... */ - /* - add_AT_lbl_id (subr_die, DW_AT_low_pc, hot_section_label); - add_AT_lbl_id (subr_die, DW_AT_high_pc, hot_section_end_label); - add_AT_lbl_id (subr_die, DW_AT_lo_user, unlikely_section_label); - add_AT_lbl_id (subr_die, DW_AT_hi_user, cold_section_end_label); + { /* Generate pubnames entries for the split function code + ranges. */ + dw_fde_ref fde = &fde_table[current_funcdef_fde]; - add_pubname (decl, subr_die); - add_arange (decl, subr_die); - add_arange (decl, subr_die); - */ + if (fde->dw_fde_switched_sections) + { + if (dwarf_version >= 3 || !dwarf_strict) + { + /* We should use ranges for non-contiguous code section + addresses. Use the actual code range for the initial + section, since the HOT/COLD labels might precede an + alignment offset. */ + bool range_list_added = false; + if (fde->in_std_section) + { + add_ranges_by_labels (subr_die, + fde->dw_fde_begin, + fde->dw_fde_end, + &range_list_added); + add_ranges_by_labels (subr_die, + fde->dw_fde_unlikely_section_label, + fde->dw_fde_unlikely_section_end_label, + &range_list_added); + } + else + { + add_ranges_by_labels (subr_die, + fde->dw_fde_begin, + fde->dw_fde_end, + &range_list_added); + add_ranges_by_labels (subr_die, + fde->dw_fde_hot_section_label, + fde->dw_fde_hot_section_end_label, + &range_list_added); + } + add_pubname (decl, subr_die); + if (range_list_added) + add_ranges (NULL); + } + else + { + /* There is no real support in DW2 for this .. so we make + a work-around. First, emit the pub name for the segment + containing the function label. Then make and emit a + simplified subprogram DIE for the second segment with the + name post-fixed with _$hot$ or _$cold$. We use the same + linkage name for the second die so that gdb will find both + sections when given "b foo". */ + const char *name = NULL; + tree decl_name = DECL_NAME (decl); + dw_die_ref seg_die; + + /* Do the 'primary' section. */ + add_AT_lbl_id (subr_die, DW_AT_low_pc, + fde->dw_fde_begin); + add_AT_lbl_id (subr_die, DW_AT_high_pc, + fde->dw_fde_end); + /* Add it. */ + add_pubname (decl, subr_die); + add_arange (decl, subr_die); + + /* Build a minimal DIE for the secondary section. */ + seg_die = new_die (DW_TAG_subprogram, + subr_die->die_parent, decl); + + if (TREE_PUBLIC (decl)) + add_AT_flag (seg_die, DW_AT_external, 1); + + if (decl_name != NULL + && IDENTIFIER_POINTER (decl_name) != NULL) + { + name = dwarf2_name (decl, 1); + if (! DECL_ARTIFICIAL (decl)) + add_src_coords_attributes (seg_die, decl); + + add_linkage_name (seg_die, decl); + } + gcc_assert (name!=NULL); + add_pure_or_virtual_attribute (seg_die, decl); + if (DECL_ARTIFICIAL (decl)) + add_AT_flag (seg_die, DW_AT_artificial, 1); + + if (fde->in_std_section) + { + name = concat (name, "_$cold$", NULL); + add_AT_lbl_id (seg_die, DW_AT_low_pc, + fde->dw_fde_unlikely_section_label); + add_AT_lbl_id (seg_die, DW_AT_high_pc, + fde->dw_fde_unlikely_section_end_label); + } + else + { + name = concat (name, "_$hot$", NULL); + add_AT_lbl_id (seg_die, DW_AT_low_pc, + fde->dw_fde_hot_section_label); + add_AT_lbl_id (seg_die, DW_AT_high_pc, + fde->dw_fde_hot_section_end_label); + } + add_name_attribute (seg_die, name); + add_pubname_string (name, seg_die); + add_arange (decl, seg_die); + } + } + else + { + add_AT_lbl_id (subr_die, DW_AT_low_pc, fde->dw_fde_begin); + add_AT_lbl_id (subr_die, DW_AT_high_pc, fde->dw_fde_end); + add_pubname (decl, subr_die); + add_arange (decl, subr_die); + } } #ifdef MIPS_DEBUGGING_INFO