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| author | Daniel Jacobowitz <drow@false.org> | 2007-02-08 14:22:53 +0000 |
|---|---|---|
| committer | Daniel Jacobowitz <drow@false.org> | 2007-02-08 14:22:53 +0000 |
| commit | 3c77c82a9b652cf3807758f738e94462764b08b9 (patch) | |
| tree | 5825d6f8cc886f354119bb38c9c80fb506728739 | |
| parent | c1b6e682ab8a42f040c3a664ad25080779efdf53 (diff) | |
| download | gdb-3c77c82a9b652cf3807758f738e94462764b08b9.zip gdb-3c77c82a9b652cf3807758f738e94462764b08b9.tar.gz gdb-3c77c82a9b652cf3807758f738e94462764b08b9.tar.bz2 | |
* rs6000-tdep.c (bl_to_blrl_insn_p): New function.
(skip_prologue): Allow bl->blrl used by PIC code.
| -rw-r--r-- | gdb/ChangeLog | 7 | ||||
| -rw-r--r-- | gdb/rs6000-tdep.c | 30 |
2 files changed, 37 insertions, 0 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index a2fe880..727bc83 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,10 @@ +2007-02-08 Joel Brobecker <brobecker@gnat.com> + Jan Kratochvil <jan.kratochvil@redhat.com> + Daniel Jacobowitz <dan@codesourcery.com> + + * rs6000-tdep.c (bl_to_blrl_insn_p): New function. + (skip_prologue): Allow bl->blrl used by PIC code. + 2007-02-08 Mark Kettenis <kettenis@gnu.org> Daniel Jacobowitz <dan@codesourcery.com> diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c index 7c5b7da..d1ca594 100644 --- a/gdb/rs6000-tdep.c +++ b/gdb/rs6000-tdep.c @@ -902,6 +902,30 @@ store_param_on_stack_p (unsigned long op, int framep, int *r0_contains_arg) return 0; } +/* Assuming that INSN is a "bl" instruction located at PC, return + nonzero if the destination of the branch is a "blrl" instruction. + + This sequence is sometimes found in certain function prologues. + It allows the function to load the LR register with a value that + they can use to access PIC data using PC-relative offsets. */ + +static int +bl_to_blrl_insn_p (CORE_ADDR pc, int insn) +{ + const int opcode = 18; + const CORE_ADDR dest = branch_dest (opcode, insn, pc, -1); + int dest_insn; + + if (dest == -1) + return 0; /* Should never happen, but just return zero to be safe. */ + + dest_insn = read_memory_integer (dest, 4); + if ((dest_insn & 0xfc00ffff) == 0x4c000021) /* blrl */ + return 1; + + return 0; +} + static CORE_ADDR skip_prologue (CORE_ADDR pc, CORE_ADDR lim_pc, struct rs6000_framedata *fdata) { @@ -1133,6 +1157,12 @@ skip_prologue (CORE_ADDR pc, CORE_ADDR lim_pc, struct rs6000_framedata *fdata) to save fprs??? */ fdata->frameless = 0; + + /* If the return address has already been saved, we can skip + calls to blrl (for PIC). */ + if (lr_reg != -1 && bl_to_blrl_insn_p (pc, op)) + continue; + /* Don't skip over the subroutine call if it is not within the first three instructions of the prologue and either we have no line table information or the line info tells |