diff options
Diffstat (limited to 'gdb/hppa-tdep.c')
| -rw-r--r-- | gdb/hppa-tdep.c | 34 |
1 files changed, 33 insertions, 1 deletions
diff --git a/gdb/hppa-tdep.c b/gdb/hppa-tdep.c index 51d8385..37bab73 100644 --- a/gdb/hppa-tdep.c +++ b/gdb/hppa-tdep.c @@ -1725,6 +1725,7 @@ hppa_frame_cache (struct frame_info *next_frame, void **this_cache) the current function (and is thus equivalent to the "saved" stack pointer. */ CORE_ADDR this_sp = frame_unwind_register_unsigned (next_frame, HPPA_SP_REGNUM); + CORE_ADDR fp; if (hppa_debug) fprintf_unfiltered (gdb_stdlog, " (this_sp=0x%s, pc=0x%s, " @@ -1733,7 +1734,38 @@ hppa_frame_cache (struct frame_info *next_frame, void **this_cache) paddr_nz (frame_pc_unwind (next_frame)), paddr_nz (prologue_end)); - if (frame_pc_unwind (next_frame) >= prologue_end) + /* Check to see if a frame pointer is available, and use it for + frame unwinding if it is. + + There are some situations where we need to rely on the frame + pointer to do stack unwinding. For example, if a function calls + alloca (), the stack pointer can get adjusted inside the body of + the function. In this case, the ABI requires that the compiler + maintain a frame pointer for the function. + + The unwind record has a flag (alloca_frame) that indicates that + a function has a variable frame; unfortunately, gcc/binutils + does not set this flag. Instead, whenever a frame pointer is used + and saved on the stack, the Save_SP flag is set. We use this to + decide whether to use the frame pointer for unwinding. + + fp should never be zero here; checking just in case. + + TODO: For the HP compiler, maybe we should use the alloca_frame flag + instead of Save_SP. */ + + fp = frame_unwind_register_unsigned (next_frame, HPPA_FP_REGNUM); + + if (frame_pc_unwind (next_frame) >= prologue_end + && u->Save_SP && fp != 0) + { + cache->base = fp; + + if (hppa_debug) + fprintf_unfiltered (gdb_stdlog, " (base=0x%s) [frame pointer] }", + paddr_nz (cache->base)); + } + else if (frame_pc_unwind (next_frame) >= prologue_end) { if (u->Save_SP && trad_frame_addr_p (cache->saved_regs, HPPA_SP_REGNUM)) { |