search for: dw_op_llvm_memori

It's worth remembering that there are two syntactically similar but semantically different kinds of "expression" in DWARF. A DWARF expression computes a value; if the available value is a pointer, you add DW_OP_deref to express the pointed-to value. A DWARF location expression computes a location, and adds various operators to express locations that a (value) expression cannot, such

On Fri, Sep 8, 2017 at 10:32 AM, Adrian Prantl <aprantl at apple.com> wrote: > > On Sep 7, 2017, at 2:18 PM, Reid Kleckner <rnk at google.com> wrote: > > > > On Thu, Sep 7, 2017 at 11:11 AM, Robinson, Paul <paul.robinson at sony.com> > wrote: > >> Different intrinsics sounds like a good solution to me. J > >> > >> So what happens

Debug info today handles two cases reasonably well: 1. At -O0, dbg.declare does a good job describing variables that live at some known stack offset 2. With optimizations, variables promoted to SSA can be described with dbg.value This leaves behind a large hole in our optimized debug info: variables that cannot be promoted, typically because they are address-taken. This is

Hi Reid, Thanks for taking this on, I'm very pleased to see improvements related to debug info for optimized code. (You can cc me on code reviews, although I'm sure a lot of the patches will be in areas I am not very familiar with.) While I have a really good handle on the DWARF standard, and have done a bunch of work with the type stuff, my understanding of IR mechanics is pretty naïve,

On Wed, Sep 6, 2017 at 5:01 PM, David Blaikie <dblaikie at gmail.com> wrote: > On Wed, Sep 6, 2017 at 2:01 PM Reid Kleckner <rnk at google.com> wrote: > >> On Wed, Sep 6, 2017 at 10:01 AM, David Blaikie <dblaikie at gmail.com> >> wrote: >> >>> I guess you described this already, but talking it through for >>> myself/maybe others will

On Wed, Sep 6, 2017 at 10:01 AM, David Blaikie <dblaikie at gmail.com> wrote: > On Tue, Sep 5, 2017 at 1:00 PM Reid Kleckner via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > >> LLVM SSA values obviously do not have an address that we can take and >> they don’t live in registers, so neither the default memory location model >> nor DW_OP_regN make sense

On Thu, Sep 7, 2017 at 11:11 AM, Robinson, Paul <paul.robinson at sony.com> wrote: > Different intrinsics sounds like a good solution to me. J > > > > So what happens with the case where a variable is registerized but later > we decide to spill it? Presumably we'd have a dbg.addr to point to the > spill slot. In past compilers I've used, spill slots were

On Thu, Sep 7, 2017 at 9:46 AM, David Blaikie <dblaikie at gmail.com> wrote: > Feels to me like bugs rather than inconsistencies (I'd think of an > inconsistency as "we do X over here intentionally and Y over here > intentionally but they're in contradiction to one another") > The DBG_VALUE MachineInstr actually already has a way to indicate that the computed

I chatted with Chandler in person and came up with what I think is a much simpler design than my previous design in the thread titled "RFC: Introduce DW_OP_LLVM_memory to describe variables in memory with dbg.value". The crux of the problem in that thread is that we need a representation, particularly in the middle-end, to describe a variables address, at a particular program point.