From f219aedc69cffe0b3ef3d455d7c2f4ed6c141d8d Mon Sep 17 00:00:00 2001 From: Kevin Buettner Date: Sat, 14 Jul 2007 00:15:50 +0000 Subject: [PATCH] * mep-tdep.c (mep_analyze_prologue): Update comment for BRA instruction case. --- gdb/ChangeLog | 5 +++++ gdb/mep-tdep.c | 15 +++++++++++++-- 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index de167a6..f211744 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2007-07-13 Kevin Buettner + + * mep-tdep.c (mep_analyze_prologue): Update comment for BRA + instruction case. + 2007-07-12 Kevin Buettner * mep-tdep.c (IS_BRA, BRA_DISP): New macros. diff --git a/gdb/mep-tdep.c b/gdb/mep-tdep.c index 5d60437..01baab3 100644 --- a/gdb/mep-tdep.c +++ b/gdb/mep-tdep.c @@ -1812,13 +1812,24 @@ mep_analyze_prologue (CORE_ADDR start_pc, CORE_ADDR limit_pc, } else if (IS_BRA (insn) && BRA_DISP (insn) > 0) { - /* When a loop appears as the first statement as a function + /* When a loop appears as the first statement of 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. */ + no longer be associated with the prologue. + + Note that we only consider forward branches here. We + presume that a forward branch is being used to skip over + a loop body. + + A backwards branch is covered by the default case below. + If we were to encounter a backwards branch, that would + most likely mean that we've scanned through a loop body. + We definitely want to stop the prologue scan when this + happens and that is precisely what is done by the default + case below. */ next_pc = pc + BRA_DISP (insn); after_last_frame_setup_insn = next_pc; break; -- 2.7.4