similar to: [LLVMdev] Info on byval attributes

Hello, As far as I know, there is no MPX pass in LLVM (though the x86-64 backend already declares MPX registers and instructions). I wonder if anyone is currently working on the LLVM pass for MPX instrumentation, similar to Pointer Checker in gcc. If yes, could anyone elaborate on the status and accessability to other researchers? And if any help is needed? Prof. Santosh Nagarakatte, the author

Hi all, I am testing link time optimizations with clang on linux x86_64 machine running Ubuntu Maverick. I am using clang with llvm release-3.0 I followed the instructions on http://llvm.org/docs/LinkTimeOptimization.html However, when I try to compile with one file being bitcode and other being native code exactly as shown in the documentation, I get the following errors clang a.o main.o -o

Hi, Can you add the following two publications from our group to the LLVM publications page. - *Alive-FP: Automated Verification of Floating Point Based Peephole Optimizations in LLVM [pdf] <http://www.cs.rutgers.edu/~santosh.nagarakatte/papers/alive-fp-sas16.pdf> *David Menendez, Santosh Nagarakatte, and Aarti Gupta *To Appear in the Proceedings of the 23rd Static Analysis

Hi - help! I have read through previous threads on the subject of 'byval' e.g. https://groups.google.com/forum/#!topicsearchin/llvm-dev/Exact$20meaning$20of$20byval/llvm-dev/cyRZyXcMCNI https://groups.google.com/forum/#!topicsearchin/llvm-dev/$20byval/llvm-dev/uk4uiK93jeM https://groups.google.com/forum/#!topicsearchin/llvm-dev/byval/llvm-dev/46Tv0lSRwBg and read through code

Hi all, I have been trying to understand the use of undef in both sequential and concurrent programs. >From the LLVM Language Reference Manual, I see the following definition of undef. "Undef can be used anywhere a constant is expected, and indicates that the user of the value may receive an unspecified bit-pattern". LLVM Language Reference manual also demonstrates how optimizers

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 integer. I didn't find a

The docs say "[byval] indicates that the pointer parameter should really be passed by value to the function. 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." I am not sure what this means though - when I generate code from the LLVM assembly, do I need to do anything with byval?

Hi Tim, Thank you for the input. I think I follow you. I believe the LowerCall is doing what it needs to do - passing pointer either on the stack or in register as per ABI. The LowerFormalArguments() is where I am stuck. LowerFormalArguments () calls CCInfo.AnalyzeFormalArguments(Ins, CC_XCore), which calls the CC_XCore(). This is where I placed the CCIfByVal<CCPassByVal<0,4>> which

LLVM developers, Can you add the following paper to the publication list? "Formal Verification of SSA Optimizations for LLVM" Jianzhou Zhao, Santosh Nagarakatte, Milo M K Martin and Steve Zdancewic Proceedings of the 34th ACM SIGPLAN Conference on Programming Language Design and Implementation (PLDI) 2013 link to ACM DL:

Hello, I am seeking a clarification of the semantics of 'byval' parameter attribute in llvm IR. Let's assume the ABI says the caller should create the 'hidden copy' of the pointee. My question is which part of the compiler chain should generate the alloca and copy code. My understanding is that it is the target code generator, not the provider of the llvm IR. But given the

Hi, after working with llvm for a while, I'm still a little confused with the meaning of the 'byval' attribute. From the langref: "This indicates that the pointer parameter should really be passed by value to the function. 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.

Hi, There are minor errors in the revised documentation on writing an llvm pass. In Quick Start -- Writing Hello World section and in basic code required section, The following should be changed from Hello() : FunctionPass(&ID) {} to Hello() : FunctionPass(ID) {} Similarly in the whole .cpp file Santosh -- Santosh G Nagarakatte, PhD Student, Computer and Information Science

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 exist and may complicate

Hi Robert, > I tried adding to the XCoreCallingConv.td: > CCIfByVal<CCPassByVal<0,4>> // pushes pointer to the stack This looks sensible to me. After that it comes down to cooperation between XCoreISelLowering's LowerFormalArguments and LowerCall functions. LowerFormalArguments is at the beginning of a function and is responsible for taking arguments out of

On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte <santosh.nagarakatte at gmail.com> wrote: > Hi all, > > I have been trying to understand the use of undef in both sequential > and concurrent programs. > > >From the LLVM Language Reference Manual, I see the following > definition of undef. > "Undef can be used anywhere a constant is expected, and indicates

> 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

Matthijs Kooijman wrote: > Hi, > > after working with llvm for a while, I'm still a little confused with the > meaning of the 'byval' attribute. From the langref: > > "This indicates that the pointer parameter should really be passed by value to > the function. The attribute implies that a hidden copy of the pointee is made > between the caller and the

I'm still in need for moderators for the following sessions: > Moderator #3 (11:15-12:45, Regency 1) > Verified LLVM: Formalizing the semantics of the LLVM Intermediate Representation for Verified Program Transformations- Santosh Nagarakatte, University of Pennsylvania/Rutgers University > Integrated Security, using LLVM for Dynamic and Static Security Tasks- Jared Carlson,

On Mon, Aug 22, 2011 at 8:46 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >> On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte >> <santosh.nagarakatte at gmail.com> wrote: >>> Hi all, >>> >>> I have been trying to understand the use of undef in

On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte > <santosh.nagarakatte at gmail.com> wrote: >> Hi all, >> >> I have been trying to understand the use of undef in both sequential >> and concurrent programs. >> >> >From the LLVM Language Reference Manual, I