54 lines
2.1 KiB
Diff
54 lines
2.1 KiB
Diff
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[gdb/tdep, rs6000] Don't skip system call in skip_prologue
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I ran into a case where a breakpoint on _exit never triggered, because it was
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set past the end of the _exit prologue, past the end of the exit_group system
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call (which does not return).
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More concretely, the breakpoint was set at the last insn show here:
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...
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Dump of assembler code for function _exit:
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0x00007ffff7e42ea0 <+0>: 12 00 4c 3c addis r2,r12,18
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0x00007ffff7e42ea4 <+4>: 60 43 42 38 addi r2,r2,17248
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0x00007ffff7e42ea8 <+8>: 00 00 00 60 nop
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0x00007ffff7e42eac <+12>: f8 ff e1 fb std r31,-8(r1)
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0x00007ffff7e42eb0 <+16>: 78 1b 7f 7c mr r31,r3
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0x00007ffff7e42eb4 <+20>: f0 ff c1 fb std r30,-16(r1)
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0x00007ffff7e42eb8 <+24>: ea 00 00 38 li r0,234
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0x00007ffff7e42ebc <+28>: a0 8b 22 e9 ld r9,-29792(r2)
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0x00007ffff7e42ec0 <+32>: 78 fb e3 7f mr r3,r31
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0x00007ffff7e42ec4 <+36>: 14 6a c9 7f add r30,r9,r13
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0x00007ffff7e42ec8 <+40>: 02 00 00 44 sc
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0x00007ffff7e42ecc <+44>: 26 00 00 7c mfcr r0
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0x00007ffff7e42ed0 <+48>: 00 10 09 74 andis. r9,r0,4096
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...
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Fix this by treating system calls the same as branches in skip_prologue:
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by default, don't skip, such that the breakpoint is set at 0x00007ffff7e42eb8
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instead.
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Tested on ppc64le-linux, on a power 8 machine.
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Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28527
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---
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gdb/rs6000-tdep.c | 6 ++++++
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1 file changed, 6 insertions(+)
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diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c
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index 826f0266ed8..9ac5db57898 100644
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--- a/gdb/rs6000-tdep.c
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+++ b/gdb/rs6000-tdep.c
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@@ -2137,6 +2137,12 @@ skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc, CORE_ADDR lim_pc,
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/* Never skip branches. */
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break;
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+ /* Test based on opcode and mask values of
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+ powerpc_opcodes[svc..svcla] in opcodes/ppc-opc.c. */
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+ if ((op & 0xffff0000) == 0x44000000)
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+ /* Never skip system calls. */
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+ break;
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+
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if (num_skip_non_prologue_insns++ > max_skip_non_prologue_insns)
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/* Do not scan too many insns, scanning insns is expensive with
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remote targets. */
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