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-rw-r--r--gdb/ChangeLog6
-rw-r--r--gdb/alpha-tdep.c54
2 files changed, 59 insertions, 1 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 23d6a7b..d7f1b98 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+Sat Dec 2 03:02:21 1995 Peter Schauer (pes@regent.e-technik.tu-muenchen.de)
+
+ * alpha-tdep.c (heuristic_proc_desc): Add heuristic to
+ determine the return address register, needed for OSF/1-3.2C.
+ * config/alpha/tm-alpha.h (T7_REGNUM, T9_REGNUM): Define.
+
Fri Dec 1 07:23:57 1995 Michael Meissner <meissner@tiktok.cygnus.com>
* ppcbug-rom.c (ppcbug_cmds): Turn on MO_GETMEM_READ_SINGLE
diff --git a/gdb/alpha-tdep.c b/gdb/alpha-tdep.c
index 622ee44..7fbf642 100644
--- a/gdb/alpha-tdep.c
+++ b/gdb/alpha-tdep.c
@@ -359,6 +359,7 @@ heuristic_proc_desc(start_pc, limit_pc, next_frame)
int frame_size;
int has_frame_reg = 0;
unsigned long reg_mask = 0;
+ int pcreg = -1;
if (start_pc == 0)
return NULL;
@@ -388,17 +389,68 @@ heuristic_proc_desc(start_pc, limit_pc, next_frame)
int reg = (word & 0x03e00000) >> 21;
reg_mask |= 1 << reg;
temp_saved_regs.regs[reg] = sp + (short)word;
+
+ /* Starting with OSF/1-3.2C, the system libraries are shipped
+ without local symbols, but they still contain procedure
+ descriptors without a symbol reference. GDB is currently
+ unable to find these procedure descriptors and uses
+ heuristic_proc_desc instead.
+ As some low level compiler support routines (__div*, __add*)
+ use a non-standard return address register, we have to
+ add some heuristics to determine the return address register,
+ or stepping over these routines will fail.
+ Usually the return address register is the first register
+ saved on the stack, but assembler optimization might
+ rearrange the register saves.
+ So we recognize only a few registers (t7, t9, ra) within
+ the procedure prologue as valid return address registers.
+
+ FIXME: Rewriting GDB to access the procedure descriptors,
+ e.g. via the minimal symbol table, might obviate this hack. */
+ if (pcreg == -1
+ && cur_pc < (start_pc + 20)
+ && (reg == T7_REGNUM || reg == T9_REGNUM || reg == RA_REGNUM))
+ pcreg = reg;
}
else if (word == 0x47de040f) /* bis sp,sp fp */
has_frame_reg = 1;
}
+ if (pcreg == -1)
+ {
+ /* If we haven't found a valid return address register yet,
+ keep searching in the procedure prologue. */
+ while (cur_pc < (limit_pc + 20) && cur_pc < (start_pc + 20))
+ {
+ char buf[4];
+ unsigned long word;
+ int status;
+
+ status = read_memory_nobpt (cur_pc, buf, 4);
+ if (status)
+ memory_error (status, cur_pc);
+ cur_pc += 4;
+ word = extract_unsigned_integer (buf, 4);
+
+ if ((word & 0xfc1f0000) == 0xb41e0000 /* stq reg,n($sp) */
+ && (word & 0xffff0000) != 0xb7fe0000) /* reg != $zero */
+ {
+ int reg = (word & 0x03e00000) >> 21;
+ if (reg == T7_REGNUM || reg == T9_REGNUM || reg == RA_REGNUM)
+ {
+ pcreg = reg;
+ break;
+ }
+ }
+ }
+ }
+
if (has_frame_reg)
PROC_FRAME_REG(&temp_proc_desc) = GCC_FP_REGNUM;
else
PROC_FRAME_REG(&temp_proc_desc) = SP_REGNUM;
PROC_FRAME_OFFSET(&temp_proc_desc) = frame_size;
PROC_REG_MASK(&temp_proc_desc) = reg_mask;
- PROC_PC_REG(&temp_proc_desc) = RA_REGNUM;
+ PROC_PC_REG(&temp_proc_desc) = (pcreg == -1) ? RA_REGNUM : pcreg;
PROC_LOCALOFF(&temp_proc_desc) = 0; /* XXX - bogus */
return &temp_proc_desc;
}