diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 2ab26d2ead9..edb87811823 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,15 @@ +2020-03-03 Tom Tromey + + * dwarf2/frame.c (struct dwarf2_frame_cache) + : Remove members. + (dwarf2_frame_cache): Call dwarf2_tailcall_sniffer_first. + (dwarf2_frame_prev_register): Don't call + dwarf2_tailcall_sniffer_first. + (dwarf2_append_unwinders): Don't append tailcall unwinder. + * frame-unwind.c (add_unwinder): New fuction. + (frame_unwind_init): Use it. Add tailcall unwinder. + 2020-03-03 Andrew Burgess Alok Kumar Sharma diff --git a/gdb/dwarf2/frame.c b/gdb/dwarf2/frame.c index b240a25e2d8..74488f9a8aa 100644 --- a/gdb/dwarf2/frame.c +++ b/gdb/dwarf2/frame.c @@ -959,22 +959,12 @@ struct dwarf2_frame_cache /* The .text offset. */ CORE_ADDR text_offset; - /* True if we already checked whether this frame is the bottom frame - of a virtual tail call frame chain. */ - int checked_tailcall_bottom; - /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME sequence. If NULL then it is a normal case with no TAILCALL_FRAME involved. Non-bottom frames of a virtual tail call frames chain use dwarf2_tailcall_frame_unwind unwinder so this field does not apply for them. */ void *tailcall_cache; - - /* The number of bytes to subtract from TAILCALL_FRAME frames frame - base to get the SP, to simulate the return address pushed on the - stack. */ - LONGEST entry_cfa_sp_offset; - int entry_cfa_sp_offset_p; }; static struct dwarf2_frame_cache * @@ -1037,6 +1027,8 @@ dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache) in an address that's within the range of FDE locations. This is due to the possibility of the function occupying non-contiguous ranges. */ + LONGEST entry_cfa_sp_offset; + int entry_cfa_sp_offset_p = 0; if (get_frame_func_if_available (this_frame, &entry_pc) && fde->initial_location <= entry_pc && entry_pc < fde->initial_location + fde->address_range) @@ -1049,8 +1041,8 @@ dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache) && (dwarf_reg_to_regnum (gdbarch, fs.regs.cfa_reg) == gdbarch_sp_regnum (gdbarch))) { - cache->entry_cfa_sp_offset = fs.regs.cfa_offset; - cache->entry_cfa_sp_offset_p = 1; + entry_cfa_sp_offset = fs.regs.cfa_offset; + entry_cfa_sp_offset_p = 1; } } else @@ -1195,6 +1187,10 @@ incomplete CFI data; unspecified registers (e.g., %s) at %s"), && fs.regs.reg[fs.retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED) cache->undefined_retaddr = 1; + dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache, + (entry_cfa_sp_offset_p + ? &entry_cfa_sp_offset : NULL)); + return cache; } @@ -1239,16 +1235,6 @@ dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache, CORE_ADDR addr; int realnum; - /* Check whether THIS_FRAME is the bottom frame of a virtual tail - call frame chain. */ - if (!cache->checked_tailcall_bottom) - { - cache->checked_tailcall_bottom = 1; - dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache, - (cache->entry_cfa_sp_offset_p - ? &cache->entry_cfa_sp_offset : NULL)); - } - /* Non-bottom frames of a virtual tail call frames chain use dwarf2_tailcall_frame_unwind unwinder so this code does not apply for them. If dwarf2_tailcall_prev_register_first does not have specific value @@ -1410,10 +1396,6 @@ static const struct frame_unwind dwarf2_signal_frame_unwind = void dwarf2_append_unwinders (struct gdbarch *gdbarch) { - /* TAILCALL_FRAME must be first to find the record by - dwarf2_tailcall_sniffer_first. */ - frame_unwind_append_unwinder (gdbarch, &dwarf2_tailcall_frame_unwind); - frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind); frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind); } diff --git a/gdb/frame-unwind.c b/gdb/frame-unwind.c index 35f2e82c57d..3334c472d02 100644 --- a/gdb/frame-unwind.c +++ b/gdb/frame-unwind.c @@ -27,6 +27,7 @@ #include "gdb_obstack.h" #include "target.h" #include "gdbarch.h" +#include "dwarf2/frame-tailcall.h" static struct gdbarch_data *frame_unwind_data; @@ -43,6 +44,18 @@ struct frame_unwind_table struct frame_unwind_table_entry **osabi_head; }; +/* A helper function to add an unwinder to a list. LINK says where to + install the new unwinder. The new link is returned. */ + +static struct frame_unwind_table_entry ** +add_unwinder (struct obstack *obstack, const struct frame_unwind *unwinder, + struct frame_unwind_table_entry **link) +{ + *link = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry); + (*link)->unwinder = unwinder; + return &(*link)->next; +} + static void * frame_unwind_init (struct obstack *obstack) { @@ -51,13 +64,21 @@ frame_unwind_init (struct obstack *obstack) /* Start the table out with a few default sniffers. OSABI code can't override this. */ - table->list = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry); - table->list->unwinder = &dummy_frame_unwind; - table->list->next = OBSTACK_ZALLOC (obstack, - struct frame_unwind_table_entry); - table->list->next->unwinder = &inline_frame_unwind; + struct frame_unwind_table_entry **link = &table->list; + + link = add_unwinder (obstack, &dummy_frame_unwind, link); + /* The DWARF tailcall sniffer must come before the inline sniffer. + Otherwise, we can end up in a situation where a DWARF frame finds + tailcall information, but then the inline sniffer claims a frame + before the tailcall sniffer, resulting in confusion. This is + safe to do always because the tailcall sniffer can only ever be + activated if the newer frame was created using the DWARF + unwinder, and it also found tailcall information. */ + link = add_unwinder (obstack, &dwarf2_tailcall_frame_unwind, link); + link = add_unwinder (obstack, &inline_frame_unwind, link); + /* The insertion point for OSABI sniffers. */ - table->osabi_head = &table->list->next->next; + table->osabi_head = link; return table; }