similar to: [LLVMdev] RFC: Exception Handling Proposal Revised

On 1 December 2010 09:46, Bill Wendling <wendling at apple.com> wrote: > Nor these. Basically, I want the basic block that's labeled a "landing pad" to be jumped to by only a dispatch resume or unwind edge of invoke. We could do this with the c.dtor and ch.int here, but it would mean inserting useless "cleanup dispatches" that only resume to the block (see

On Dec 1, 2010, at 1:12 AM, Renato Golin wrote: > On 1 December 2010 07:04, Bill Wendling <wendling at apple.com> wrote: >> The unwind edge from an invoke instruction jumps to a landing pad. That landing pad contains code which performs optional cleanups, and then determines which catch handler to call (if any). If no catch handlers are applicable, the exception resumes propagation

On Dec 1, 2010, at 2:37 AM, Renato Golin wrote: > On 1 December 2010 09:46, Bill Wendling <wendling at apple.com> wrote: >> Nor these. Basically, I want the basic block that's labeled a "landing pad" to be jumped to by only a dispatch resume or unwind edge of invoke. We could do this with the c.dtor and ch.int here, but it would mean inserting useless "cleanup

Hi everyone! I've been silently working on the previous exception handling proposal I published last year (http://lists.cs.uiuc.edu/pipermail/llvmdev/2009-November/027311.html). However, there were some major deficiencies in it. After discussing this further with Jim Grosbach and John McCall, we've come up with another proposal. As you can see, it incorporates the idea of

Hello everybody, I have stumbled upon a test case (the attached module is a slightly reduced version) that shows extremely reduced performance on linux compared to windows when executed using LLVM's JIT. We narrowed the problem down to the actual code being generated, the source IR on both systems is the same. Try compiling the attached module: llc -O3 -filetype=asm -o BAD.s BAD.ll Under

This is a revision of the second exception handling proposal I sent out. You can see it here: http://lists.cs.uiuc.edu/pipermail/llvmdev/2010-November/036484.html After much discussion, there are some changes to the proposal – some significant and some minor. One major point, this proposal does not address the issue of catching an exception thrown from a non-invoke instruction. However if done

Hi Bill, there are a couple of things I didn't understand about your proposal, for example how it interacts with inlining, whether it is feasible to do the "turn invoke-of-Unwind_Resume into a branch" optimization and also whether in "resumedest" you still plan to use _Unwind_Resume to continue unwinding up the stack. Could you please show what the LLVM IR would look like

On Dec 1, 2010, at 12:10 AM, John McCall wrote: > On Nov 30, 2010, at 11:04 PM, Bill Wendling wrote: >> • A landing pad must have exactly one dispatch instruction associated with it, >> and it must dominate that instruction. > > Okay, but how do we find it? > We can modify the dispatch to point back to the landing pad it's associated with. Something like: lpad:

On Wed, Dec 1, 2010 at 11:37 AM, Renato Golin <rengolin at systemcall.org> wrote: > On 1 December 2010 09:46, Bill Wendling <wendling at apple.com> wrote: >> Nor these. Basically, I want the basic block that's labeled a "landing pad" to be jumped to by only a dispatch resume or unwind edge of invoke. We could do this with the c.dtor and ch.int here, but it would

Hi, all As I'm a Chinese, be patient of my poor description below. I compiled libgcc into llvm bitcode in both big endian and little endian. and got 2 different version of function: _ashldi3, the following is the fragment of this function: little endian: ============================================= ...... target datalayout =

On Nov 30, 2010, at 11:04 PM, Bill Wendling wrote: > • A landing pad must have exactly one dispatch instruction associated with it, > and it must dominate that instruction. Okay, but how do we find it? Looks good, though! John.

Hi Bill, this proposal seems strangely complicated. I don't see the advantage of the dispatch instruction over just attaching the information to each invoke. Right now you have invoke void @_Z3foov() to label %invcont unwind label %catch.handlers catch.handlers: landingpad dispatch resume to label %... catches [ %struct.__fundamental_type_info_pseudo* @_ZTIi, label

On 8 December 2010 18:45, Devang Patel <dpatel at apple.com> wrote: > I do not know EH or details of these proposals. But do not forget, basic blocks are merged/split/deleted, instructions are added/removed/moved/copied/replaced. Indeed. Having the information in the invoke kinda alleviates this problem, but removing the invoke syntax will bring that back. One way to merge two basic

So my best bet is to try and work in reg2mem mode and then go back to mem2reg? I'm curious, it seems though when you split a block that the phis get updated, right? On Thu, Feb 2, 2012 at 5:05 PM, Eric Christopher <echristo at apple.com> wrote: > Not that I'm aware of. > > -eric > > On Feb 2, 2012, at 3:47 PM, Ryan Taylor wrote: > > So essentially I'm

---------- Forwarded message ---------- From: Ryan Taylor <ryta1203 at gmail.com> Date: Mon, Feb 6, 2012 at 10:36 AM Subject: Re: [LLVMdev] Updating PHI for Instruction Domination? To: Eric Christopher <echristo at apple.com> Since I'm not sure which instructions I might want to replicate, would it be possible to cast the Value from "PHINode::getIncomingValue" to

Hi, catch_all.cpp: 1 int main() 2 { 3 try { 4 throw 34; 5 } 6 catch (...) {} 7 } llvm-gcc -O3 -S -emit-llvm catch_all.cpp -o catch_all.ll: 1 ; ModuleID = 'catch_all.cpp' 2 target datalayout =

Hi all, I have problem with ExtractCodeRegion (CodeExtractor.cpp). My original program is as follows. bb: ... %tmp.15 = load %struct.MYSQL_ROWS** %3, align 4 ... bb1: ... %tmp.1 = load %struct.MYSQL_ROWS** %6, align 4 ... bb4: ; preds = %bb1, %bb, %entry %tmp.0 = phi %struct.MYSQL_ROWS* [ null, %entry ], [ %tmp.15, %bb ], [ %tmp.1, %bb1 ]

On May 22, 2014, at 3:51 PM, Chandler Carruth <chandlerc at google.com> wrote: > > On Thu, May 22, 2014 at 4:42 PM, Louis Gerbarg <lgg at apple.com> wrote: > The problem that the above transform is technically illegal because “When indexing into a (optionally packed) structure, only i32 integer constants are allowed (when using a vector of indices they must all be the same

Here is an alternative proposal to Bill's. It is closer to what we already have (which can be seen as a good or a bad thing!), and is also closer to what gcc does. It is more incremental than Bill's and introduces fewer new concepts. Executive summary ----------------- Remove the personality and list of catches out of eh.selector and stick them directly on invoke instructions. The

On Nov 24, 2010, at 2:59 AM, Renato Golin wrote: > Hi Bill, > > First, I like the idea of being more expressive in IR, since the old > exception handling style didn't quite express exception handling, but > alternate paths (resume/unwind). That made DwarfException.cpp a big > hack. ;) > > It also makes the front-end engineer's life a lot easier, since there >