>>> On 11.08.14 at 15:26, <dvlas...@redhat.com> wrote: > On 08/11/2014 10:40 AM, Jan Beulich wrote: >>>>>> CFI_ESCAPE 0x0f /* DW_CFA_def_cfa_expression */, 6, \ >>>>>> 0x77 /* DW_OP_breg7 */, 0, \ >>>>>> 0x06 /* DW_OP_deref */, \ >>>>>> - 0x08 /* DW_OP_const1u */, SS+8-RBP, \ >>>>>> + 0x08 /* DW_OP_const1u */, SS+8, \ >>>>>> 0x22 /* DW_OP_plus */ >>>>>> /* We entered an interrupt context - irqs are off: */ >>>>>> TRACE_IRQS_OFF > ... > ... >>>> While we are at it, what this CFI_ESCAPE thing does here? >>>> As usual, it has no comment :/ >> >> Each of its lines has a comment; with other CFI annotations not >> each having comments, I don't see what else is needed here. > > The existing comments explain what every byte means. > They are useful if CFI-literate reader wants to check correctness > of the encoding of this annotation. > > There is no overall comment what this CFI annotation > *achieves*. In human language, what do we say > to DWARF decoder here?
Short answer: DW_CFA_def_cfa_expression. Longer response: Just like I said before, what you're asking for is identical to ask for each other CFI annotation to get a comment associated to tell you what it's doing, which I don't think you really mean to ask for. (Our main problem here is that we can't specify expressions with the .cfi_* gas directives, and hence have to resort to .cfi_escape.) Jan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
