search for: byval

Hi, In the past months, several options have been presented for making byval (and similar attributes, such as inalloca or sret) work with opaque pointers. The main two I've seen were byval(T) and byval(N) where N is the size of T. They both have their upsides and downsides, for example: byval(T) would be a type-parametric attribute, which, AFAIK, does not already exis...

> Do all tests need it? Align is just for non-default alignment (> align(1)) so it may be OK for the tests to omit it & it's probably not right to /require/ an align attribute on a byval parameter. I've had to fix some of the tests which checked that the right alignment was applied, by looking at the generated asm, but had no "align A" attributes and relied on the target alignment guessing, which I had taken out in my experimental implementation. The rest of the tes...

I have three modules: ----------------------------------------------------------------- s1.ll: %0 = type <{ i32, i32 }> define void @s1(%0* byval %myStruct) nounwind { return: ret void } ----------------------------------------------------------------- s2.ll: %0 = type <{ i32, i32 }> define void @s2(%0* byval %myStruct) nounwind { return: ret void } ----------------------------------------------------------------- s3.ll: %0 = typ...

Hi Tim, Thought about it last night and was coming to the same conclusion. 1. it cant be done at the end during lowering (target backend). 2. it should be part of llvm as the byVal needs to be handled. As a twist, I have been told that llvm-gcc can lower byVal into memcpy in the callee. I may take a look at this. I wonder if it ever emits 'byVal'... I still feel I don't understand enough about where byVal is used or what it means. Is it *only* used as an attribu...

On May 9, 2011, at 1:41 PM, Renato Golin wrote: [snip] > One example is the struct byval. The ARM back-end still doesn't > support struct byval (maybe now it does, I was away for a while), The ARM backend now supports struct byval for APCS. Extending it to support AAPCS shouldn't be too difficult. Alas, I won't have time to revisit this in the near future. stuart

...Xiaoyi, this looks like a bug to me - please file a bug report. Ciao, Duncan. On 01/11/12 04:35, Guo, Xiaoyi wrote: > I have three modules: > ----------------------------------------------------------------- > s1.ll: > > %0 = type <{ i32, i32 }> > > define void @s1(%0* byval %myStruct) nounwind { > return: > ret void > } > ----------------------------------------------------------------- > s2.ll: > > %0 = type <{ i32, i32 }> > > define void @s2(%0* byval %myStruct) nounwind { > return: > ret void > } > ----------------...

LLVM developers, I was wondering if the program would still be safe if I strip the byval attributes from the parameters in the entire bitcode. LLVM language reference manual states that "The attribute implies that a hidden copy of the pointee is made between the caller and the callee, so the callee is unable to modify the value in the callee. This attribute is only valid on LLVM...

On Wed, May 11, 2011 at 11:42 PM, Stuart Hastings <stuart at apple.com> wrote: > > On May 9, 2011, at 1:41 PM, Renato Golin wrote: > > [snip] > >> One example is the struct byval. The ARM back-end still doesn't >> support struct byval (maybe now it does, I was away for a while), > > The ARM backend now supports struct byval for APCS.  Extending it to support AAPCS shouldn't be too difficult.  Alas, I won't have time to revisit this in the near future...

It is problematic when byval argument is not from address space 0. When the default alloca address space is 0, should we consider this IR illegal? define internal i32 @bar(i32 addrspace(1)* byval %a) alwaysinline From: Reid Kleckner [mailto:rnk at google.com] Sent: Tuesday, September 25, 2018 2:38 PM To: Pan, Wei <we...

Hello all, I'm trying to find the pass that would convert from: define void @main(%struct* byval %ptr) { %val = load %struct* %ptr %val.ptr = alloca %struct store %struct %val, %struct* %val.ptr call void @extern_func(%struct* byval %val.ptr) ret void } to this: define void @main(%struct* byval %ptr) { call void @extern_func(%struct* byval %ptr) ret void } First, am I missing s...

...and IR verifier. -----Original Message----- From: Friedman, Eli [mailto:efriedma at codeaurora.org] Sent: Tuesday, September 25, 2018 3:07 PM To: Pan, Wei <wei.pan at intel.com>; Reid Kleckner <rnk at google.com> Cc: llvm-dev <llvm-dev at lists.llvm.org> Subject: Re: [llvm-dev] byval argument causes llvm to crash after inlining Probably, yes: lowering a byval parameter requires allocating space on the stack, so it has to be in the same address space. -Eli On 9/25/2018 3:00 PM, Pan, Wei via llvm-dev wrote: > It is problematic when byval argument is not from address space 0...

Hi Tim, Correction to my last email. What I should have said is that the new pointer is used by the callee rather than the original byVal pointer arg. (the byVal pointer arg remains but is not used by the callee). viz: define void @f1(%struct.tag* byval) { entry: %st = alloca %struct.tag, align 4 %1 = bitcast %struct.tag* %st to i8* %2 = bitcast %struct.tag* %0 to i8* call void @llvm.memcpy.p0i8.p0i8.i32(i8* %1, i8* %2, i32 8...

...Antoine Pitrou via llvm-dev < llvm-dev at lists.llvm.org>: > On Wed, 20 Jan 2016 00:47:56 +0200 > "Eddy B. via llvm-dev" <llvm-dev at lists.llvm.org> wrote: > > > > I would love to know your thoughts on this, and more specifically: > > Which of the 3 (byval(T), byval(N) and byval + dereferenceable + align) > > do you think would provide the easiest transition path for front-ends? > > We (llvmlite and Numba) don't use byval specifically but, were we to use > it, I think byval(T) would by far be the easiest for us. By contrast, >...

Hi Robert, suppose you have a "byval" argument with type T*, and the caller passes a T* called %X for it, while in the callee the argument is called %Y. The IR level semantics are: (1) a copy should be made of *%X. Whether the callee or the caller makes the copy depends on the platform ABI. (2) in the callee, %Y refers to...

...eping types on GEP, > You mean rather than just dropping gep entirely & doing manual pointer arithmetic? (& moving inbounds to an attribute on pointer addition, I guess?) > then IMO we should keep them on allocas and globals. It keeps the IR human > readable. > & what of byval, then? Do you agree with Chandler's argument from analogy between byval, alloca, and globals? (oh, and I should look at inalloca a bit too - it looks like it uses the getByValTypeAlignment too... ) - David > > We're pretty close to mandatory data layout, so computing the size and...

Hello guys, For single scalar pointer parameter, we have 'byval' to specify the pointee is not changed. But for base+range parameters like: declare void @_gfortran_transfer_integer_write(%struct.__st_parameter_dt*, i8*, i32) (This is the fortran runtime api to 'printf' one integer) The 2nd & 3rd args are used to specify the memory of that intege...

On May 12, 2011, at 12:30 AM, Sandeep Patel wrote: > On Wed, May 11, 2011 at 11:42 PM, Stuart Hastings <stuart at apple.com> wrote: >> >> On May 9, 2011, at 1:41 PM, Renato Golin wrote: >> >> [snip] >> >>> One example is the struct byval. The ARM back-end still doesn't >>> support struct byval (maybe now it does, I was away for a while), >> >> The ARM backend now supports struct byval for APCS. Extending it to support AAPCS shouldn't be too difficult. Alas, I won't have time to revisit this in th...

Hello, With the following reduced test case, cmd "opt -always-inline t.ll" crashes after inlining. Notice that byval argument %a will be remapped to %1 below, and consequently produces an illegal store. %1 = alloca i32, align 4 store i32 * %1, i32 addrspace(1)** %a.addr, align 8 Looks like Inliner assumes that byval arguments are from address space 0. Or this is just a bug in inliner? Thanks, Wei t.ll: defin...

...e early on in the IR in my thinking - to allow optimisation if the data is only ever read. I've thought that once or twice when dealing with ABIs myself. That's certainly another possibility in your case. You could create a separate FunctionPass that gets executed early on and replaces all byval calls and functions with the correct memcpys. It wouldn't work for other targets because they need more control over just where the copy ends up, but it sounds like you shouldn't have an issue. > So, can it be done in the llvm? Yes, in multiple ways. > Should it be done in the llv...

Hello, I'm trying to make a function for using wine_get_unix_file_name in VB6 programs. Private Declare Function lstrcpyA Lib "kernel32.dll" (ByVal lpString1 As String, ByVal lpString2 As Long) As Long Public Declare Function GetProcessHeap Lib "kernel32" () As Long Public Declare Function HeapFree Lib "kernel32" (ByVal hHeap As Long, ByVal dwFlags As Long, IpMem As Any) As Long Public Declare Function wine_get_unix_file...