[commit] mep-tdep.c: prologue analyzer update

Kevin Buettner
2007-07-13T00:01:58Z

I've just committed the patch below. It fixes a gdb.base/break.exp
failure when using a gcc-4.x based compiler. (See the comment in the
patch for a full explanation.)

* mep-tdep.c (IS_BRA, BRA_DISP): New macros.
(mep_analyze_prologue): Add case for BRA instruction.

Index: mep-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/mep-tdep.c,v
retrieving revision 1.5
diff -u -p -r1.5 mep-tdep.c
--- mep-tdep.c 16 Jun 2007 17:16:25 -0000 1.5
+++ mep-tdep.c 12 Jul 2007 23:52:31 -0000
@@ -1578,6 +1578,10 @@ mep_get_insn (CORE_ADDR pc, long *insn)
#define MOV_TARGET(i) (FIELD (i, 24, 4))
#define MOV_SOURCE(i) (FIELD (i, 20, 4))

+/* BRA disp12.align2 1011_dddd_dddd_ddd0 xxxx_xxxx_xxxx_xxxx */
+#define IS_BRA(i) (((i) & 0xf0010000) == 0xb0000000)
+#define BRA_DISP(i) (SFIELD (i, 17, 11) << 1)
+

/* This structure holds the results of a prologue analysis. */
struct mep_prologue
@@ -1806,6 +1810,19 @@ mep_analyze_prologue (CORE_ADDR start_pc

reg[rn] = pv_area_fetch (stack, addr, 4);
}
+ else if (IS_BRA (insn) && BRA_DISP (insn) > 0)
+ {
+ /* When a loop appears as the first statement as a function
+ body, gcc 4.x will use a BRA instruction to branch to the
+ loop condition checking code. This BRA instruction is
+ marked as part of the prologue. We therefore set next_pc
+ to this branch target and also stop the prologue scan.
+ The instructions at and beyond the branch target should
+ no longer be associated with the prologue. */
+ next_pc = pc + BRA_DISP (insn);
+ after_last_frame_setup_insn = next_pc;
+ break;
+ }
else
/* We've hit some instruction we don't know how to simulate.
Strictly speaking, we should set every value we're