similar to: [LLVMdev] RFC: Exception Handling Rewrite

Hi Peter, Thanks for pointing this out. Some us who are concerned with codegen have discussed the problem. Although the details aren't decided, you can be sure that at the MachineInstr level we won't have a landindpadInst to model liveness of exception values. Any physical registers set by the personality function will be considered live immediately after the call on the unwind path.

Andrew, yes, my brain-bad, soon after I hit the Send button I realized it is the InvokeInst that starts the lifetime of those hard-registers, not the LandingpadInst, but you beat me to the reply. -Peter Lawrence. On Aug 4, 2011, at 4:16 PM, Andrew Trick wrote: > Hi Peter, > > Thanks for pointing this out. Some us who are concerned with > codegen have discussed

Guys, on second thought... doesn't making the exception registers live from the InvokeInst to the LandingpadInst create problems for critical-edge-splitting ? if a landingpad-edge is critical and needs to be split, won't we be creating and inserting a new BB between the "invoke-block" and the "landingpad-block", and if we do then isn't there the

On Aug 5, 2011, at 10:57 AM, Peter Lawrence wrote: > However it seems that if a landingpad-block has multiple predecessors (often the case, > multiple InvokeInst in the main body of a try-statement all go to the same landingpad- > block), then you cannot move the LandingpadInst in order to break a critical edge unless > you do it for _all_ landingpad-block predecessor edges

On Aug 1, 2011, at 11:13 PM, Bill Wendling wrote: >>> The 'landingpad' instruction replaces the current 'llvm.eh.exception' and >>> 'llvm.eh.selector' intrinsics. >>> >>> // Syntax: >>> >>> %res = landingpad<somety> personality<ty> <pers_fn> <clause>+ >>> >>> where

Bill, ooops, yes, I described the meaning of "throw(A)" backwards, but I still think my example shows why you cannot merge LandingpadInst while inlining because multiple filter-lists on a LandingpadInst don't make sense. Perhaps I'm reading your original spec wrong, perhaps I'm mis-reading Duncan's emails, but I read them to mean that your syntax supports

On Aug 5, 2011, at 10:57 AM, Peter Lawrence wrote: > Bill, > ooops, yes, I described the meaning of "throw(A)" backwards, I thought that might be the case. :) > but I still > think my example shows why you cannot merge LandingpadInst while > inlining because multiple filter-lists on a LandingpadInst don't make sense. > > Perhaps I'm reading your

On Jul 31, 2011, at 11:06 AM, Duncan Sands wrote: >> //===-------------------------- >> // The 'landingpad' Instruction >> // >> >> The 'landingpad' instruction replaces the current 'llvm.eh.exception' and >> 'llvm.eh.selector' intrinsics. >> >> // Syntax: >> >> %res = landingpad<somety>

On Apr 8, 2012, at 10:40 PM, Bill Wendling wrote: > What gets returned by the landingpad instruction (%0 here) is normally a structure. LLVM doesn't typically treat aggregates as first-class citizens. In particular, you shouldn't store the whole structure to memory like you do to %5. You can use 'extractvalue' to get the different elements of the structure. If you need to

> > What? Yet another EH proposal?! This one is different from the > others in that > I'm planning to start implementing this shortly. But I want your > feedback! I've > all ready gotten a lot of feedback from Chris, John, Jim, Eric, and > many others. > Now is your turn! > > Please read this proposal and send me your comments, suggestions, > and

Hi Chris, >>> Is it intended that "cleanup ty_1, ty_2" potentially be different to >>> "cleanup ty_1 cleanup ty_2"? Perhaps this is useful for funky personality >>> functions. >>> >> Yeah. One can basically interleave the catches and filters. But having two catch or two filter clauses in a row should be semantically the same as the

Hi David, Sorry to bother you, but I would like to get some suggestions on your recent work of token type. I’m currently working on changing gc.statepoint to return a token type instead of a i32 type. The reason is that with the current implementation, gc.statepoint could potentially be fed into PHI nodes, and break RewriteStatepointsForGC pass later. Using token type would help us to avoid

While improving ADCE, i notice that for declare i32 @strlen(i8*) readnone define i32 @test() { ; invoke of pure function should not be deleted! invoke i32 @strlen( i8* null ) readnone to label %Cont unwind label %Other ; <i32>:1 [#uses=0] Cont: ; preds = %0 ret i32 0 Other: ; preds = %0 %exn = landingpad {i8*, i32} personality i32 (...)* @__gxx_personality_v0

> On Dec 1, 2015, at 11:14 PM, David Majnemer <david.majnemer at gmail.com> wrote: > > While we support 'opaque' types nested within struct types, they are not exactly battle tested: > > $ cat t.ll > %opaque_ty = type opaque > > %struct_ty = type { i32, %opaque_ty } > > define %struct_ty @f(%struct_ty* %p) { > %load = load %struct_ty,

Oh, no. I should have been more clear. The patch was not rejected, just lost in the daily shuffle. I already have my employer's approval to send this upstream, so I will prepare a patch against trunk this morning. > I proposed a similar patch to LLVM (left circular shift) around 10/2011. > > Parts of my patch did make it into trunk about a year after, but others > > did not.

On Aug 4, 2011, at 4:03 PM, Peter Lawrence wrote: > Bill, > I believe the empty-exception-specification example is a red-herring, > but that if you can construct an example where you think a landing-pad > requires multiple filter lists then I think we can then have a productive > conversation about it. > > I believe we can only get multiple filter lists in a

> I dont have a concrete design right now and I am happy to take any other ideas Three ideas come to mind, none of which are perfect: 1) I'm tempted to say that now that we have token type, landingpad should generally produce a token, the pointer should be extracted with the @llvm.eh.exceptionpointer intrinsic instead of an extractvalue, and the selector should likewise be extracted with

It seems a little backwards to me to check the landingpad's type as the first check, since the personality dictates the landingpad's type. That said, yes I see how #4 is expedient in allowing personalities using the two main types to lump themselves into EHPersonality::Unknown. As for supporting selector and exception pointer extraction for landingpad of token type, I think you'll

On Monday, July 30, 2012 12:16 AM, Cameron McInally wrote: > Hey Andy, > > I proposed a similar patch to LLVM (left circular shift) around 10/2011. > Parts of my patch did make it into trunk about a year after, but others > did not. > > At that time, my solution was to add a binary operator to the IRBuilder, > since LCS fits in nicely with the other shift operators. But,

Bill, I believe the empty-exception-specification example is a red- herring, but that if you can construct an example where you think a landing-pad requires multiple filter lists then I think we can then have a productive conversation about it. I believe we can only get multiple filter lists in a landing-pad if we attempt to merge exception-regions, and since filters are only an