On 07/14/2017 07:26 AM, Richard Henderson wrote:
On 07/13/2017 11:26 PM, Lluís Vilanova wrote:
Incrementally paves the way towards using the generic instruction translation
loop.
Signed-off-by: Lluís Vilanova <vilan...@ac.upc.edu>
Reviewed-by: Richard Henderson <r...@twiddle.net>
---
target/arm/translate.c | 53 +++++++++++++++++++++++++++++++-----------------
1 file changed, 34 insertions(+), 19 deletions(-)
diff --git a/target/arm/translate.c b/target/arm/translate.c
index b9183fc511..55bef09739 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -11917,6 +11917,33 @@ static void arm_tr_insn_start(DisasContextBase
*dcbase, CPUState *cpu)
#endif
}
+static bool arm_tr_breakpoint_check(DisasContextBase *dcbase, CPUState *cpu,
+ const CPUBreakpoint *bp)
+{
+ DisasContext *dc = container_of(dcbase, DisasContext, base);
+
+ if (bp->flags & BP_CPU) {
+ gen_set_condexec(dc);
+ gen_set_pc_im(dc, dc->pc);
+ gen_helper_check_breakpoints(cpu_env);
+ /* End the TB early; it's likely not going to be executed */
+ dc->base.is_jmp = DISAS_UPDATE;
+ } else {
+ gen_exception_internal_insn(dc, 0, EXCP_DEBUG);
+ /* The address covered by the breakpoint must be
+ included in [tb->pc, tb->pc + tb->size) in order
+ to for it to be properly cleared -- thus we
+ increment the PC here so that the logic setting
+ tb->size below does the right thing. */
+ /* TODO: Advance PC by correct instruction length to
+ * avoid disassembler error messages */
+ dc->pc += 2;
+ dc->base.is_jmp = DISAS_NORETURN;
+ }
+
+ return true;
+}
+
/* generate intermediate code for basic block 'tb'. */
void gen_intermediate_code(CPUState *cs, TranslationBlock *tb)
{
@@ -11965,28 +11992,16 @@ void gen_intermediate_code(CPUState *cs,
TranslationBlock *tb)
if (unlikely(!QTAILQ_EMPTY(&cs->breakpoints))) {
CPUBreakpoint *bp;
QTAILQ_FOREACH(bp, &cs->breakpoints, entry) {
- if (bp->pc == dc->pc) {
- if (bp->flags & BP_CPU) {
- gen_set_condexec(dc);
- gen_set_pc_im(dc, dc->pc);
- gen_helper_check_breakpoints(cpu_env);
- /* End the TB early; it's likely not going to be
executed */
- dc->base.is_jmp = DISAS_UPDATE;
Oh I see what you're doing there in the main loop.
And I see that you're copying existing behaviour.
That said, I do wonder if there's a better way.
Looking back at the original patch (5d98bf8f), there do not
seem to have been any other side effects intended; simply
"single step" any insn for which this bp condition is met.
Another way to handle this would be if we could adjust max_insns = num_insns.
That would cause the loop to exit after the current insn, with DISAS_TOO_MANY
if nothing else.
Another possibility is is_jmp = DISAS_TOO_MANY, and exit the translation loop
after the breakpoint check only for is_jmp > DISAS_TOO_MANY. That allows all
of the DISAS_TARGET_N values to exit as well.
r~
