On Jan 16, 2018, at 1:20 PM, Vedant Kumar <vsk@apple.com> wrote:
+ Adrian and Davide, since they work in this area.
Hi Raj,
On Jan 15, 2018, at 4:48 PM, Raj Barik via swift-dev <swift-dev@swift.org> > wrote:
Thanks Mark. You are right, the following assertion fails
require(!DS || DS->getParentFunction() == I->getFunction(),
"debug scope of instruction belongs to a different function");
I am not sure if we need such a check.
This check exists to ensure that the debug info generated for a program is
helpful. For example, a function with the wrong debug scope attached might
make for confusing backtraces.
It's more than just confusing backtraces. If these invariants aren't met
the LLVM IR generated from this SIL will not pass the LLVM IR verifier or
in older versions even crash LLVM.
The constraint being checked in this assertion is that each instruction
must be in a lexical scope whose top-level ancestor is the function itself.
I.e., it is not legal to move an instruction from one function to another
with updating that instruction's debug information by either reparenting it
into the new function or by creating inline information for it.
SILClonerWithScope implements this re-parenting of instructions into a new
function for you.
-- adrian
vedant
On Mon, Jan 15, 2018 at 4:16 PM, Mark Lacey <mark.lacey@apple.com> wrote:
On Jan 15, 2018, at 12:54 PM, Raj Barik <rkbarik@gmail.com> wrote:
Mark,
Thanks a lot for quick reply.
Is there any reason this interface in SILInstruction should be private?
void setDebugScope(SILBuilder &B, const SILDebugScope *DS);
In my case, I am splicing the old F into the new function NF. While
splicing retains the debug scope, the new instruction (InitRef) that I am
adding to NF is being created in some random scope (not F) even though I
explicitly make Builder's debug scope point to F's.
The assert you originally hit appears to indicate that the parentFunction
of the debug scope for an instruction should be the same as the function
the instruction is in. I am not very familiar with the requirements of our
debug information and debug scopes, but this seems like a reasonable
expectation.
I suggested looking at SILCloner because it is the primary way by which
we clone functions, and clearly has to deal with debug scopes when it does
so.
I’m not sure how much more help I can be on this matter, but perhaps
someone more knowledgable can chime in.
Mark
Best,
Raj
On Mon, Jan 15, 2018 at 9:52 AM, Mark Lacey <mark.lacey@apple.com> wrote:
I’d suggest looking at SILCloner.h as well as ScopeCloner in
SILBasicBlock.cpp to see how they are dealing with debug scopes.
Mark
> On Jan 15, 2018, at 9:24 AM, Raj Barik via swift-dev < >>> swift-dev@swift.org> wrote:
>
> Hi,
>
> I am running into a debug scope SIL Verifier error when creating a new
function (NF) from an existing one (F). Can someone point me where I am
going wrong?
>
> NF = M.createFunction(...., F->getDebugScope());
> SILBasicBlock *NFBody = NF->createBasicBlock();
> SILBuilder NFBuilder(NFBody);
> SILOpenedArchetypesTracker OpenedArchetypesTrackerNF(NF);
> NFBuilder.setOpenedArchetypesTracker(&OpenedArchetypesTrackerNF);
> NFBuilder.setCurrentDebugScope(NFBody->getParent()->getDebugScope());
> ...
> for (auto ¶m : params) { /* Assume all are generic types */
> auto GenericsSILType = ....
> auto NewArg = NFBody->createFunctionArgument(GenericSILType);
> auto Conformances = Mod->lookupConformance(...);
> auto *InitRef = NFBuilder.createInitExistentialRef( Loc,
ArgDesc.Arg->getType(), NewArg->getType().getSwiftRValueType()->getCanonicalType(),
NewArg, Conformances);
> ...
> }
>
> The InitRef instruction created above runs into SIL verifier error:
>
> SIL verification failed: debug scope of instruction belongs to a
different function: !DS || DS->getParentFunction() == I->getFunction()
> Verifying instruction:
> %0 = argument of bb0 : $τ_0_0 // user: %1
> -> %1 = init_existential_ref %0 : $τ_0_0 : $τ_0_0, $SomeProtocol //
user: %2
>
> The SIL looks correct to me though.
>
> --Raj
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