similar to: [LLVMdev] help decompiling x86 ASM to LLVM IR

James Courtier-Dutton <james.dutton at gmail.com> writes: > I am looking to decompile x86 ASM to LLVM IR. > The original C is this: > int test61 ( unsigned value ) { > int ret; > if (value < 1) > ret = 0x40; > else > ret = 0x61; > return ret; > } > > It compiles with GCC -O2 to (rather

On 3/12/2013 11:20 AM, James Courtier-Dutton wrote: > It compiles with GCC -O2 to (rather cleverly removing any branches): > 0000000000000000 <test61>: > 0: 83 ff 01 cmp $0x1,%edi > 3: 19 c0 sbb %eax,%eax > 5: 83 e0 df and $0xffffffdf,%eax > 8: 83 c0 61 add $0x61,%eax >

On 3/12/13 11:39 AM, Óscar Fuentes wrote: > James Courtier-Dutton <james.dutton at gmail.com> writes: > >> I am looking to decompile x86 ASM to LLVM IR. >> The original C is this: >> int test61 ( unsigned value ) { >> int ret; >> if (value < 1) >> ret = 0x40; >> else >> ret =

Hi, I have the x86 SBB instruction. how should I represent this in LLVM IR. (as part of a decompiler from binary to LLVM IR) Pre-conditions: %eax = 0xffffffff %edx = 0xffffffff %carry = 1 SBB %eax, %edx // %edx is the destination doing %edx = %edx - (%eax + carry) JC jump_destination1 // If the Carry flag is set, jump to jump_destination1 How do I represent this correctly in LLVM

Look at the __builtin_addc* builtins in clang. I am currently working on an optimization which transforms said intrinsics into chains of ADCs/SBBs. Michael On Jun 28, 2013, at 5:51 AM, James Courtier-Dutton <james.dutton at gmail.com> wrote: > Hi, > > I have the x86 SBB instruction. how should I represent this in LLVM > IR. (as part of a decompiler from binary to LLVM IR)

On 5/7/2012 11:45 AM, James Courtier-Dutton wrote: > On 7 May 2012 16:31, John Criswell<criswell at illinois.edu> wrote: >> Given that you've completed steps one and two (i.e., you've converted the >> binary instructions to LLVM IR and then discovered basic blocks), then yes, >> LLVM's current analysis passes should help you with this third step. LLVM

On 7 May 2012 16:31, John Criswell <criswell at illinois.edu> wrote: > On 5/7/12 5:47 AM, James Courtier-Dutton wrote: >> >> Hi, >> >> I am writing a decompiler. I was wondering if some of LLVM could be >> used for a decompiler. >> There are several stages in the decompiler process. >> 1) Take binary and create a higher level representation of it.

Hi, I am writing a decompiler. I was wondering if some of LLVM could be used for a decompiler. There are several stages in the decompiler process. 1) Take binary and create a higher level representation of it. Like RTL. 2) The output is then broken into blocks or nodes, each block ends in a CALL, JMP, RET, or 2-way or multiway conditional JMP. 3) The blocks or nodes are then analyzed for

On 12 March 2013 16:39, Óscar Fuentes <ofv at wanadoo.es> wrote: > > This is not possible, except for specific cases. > > Consider this code: > > long foo(long *p) { > ++p; > return *p; > } > > The X86 machine code would do something like > > add %eax, 4 > > for `++p', but for x86_64 it would be > > add %rax, 8 > > But you

> -----Original Message----- > On Behalf Of James Courtier-Dutton > To: John Criswell > > On 7 May 2012 16:31, John Criswell <criswell at illinois.edu> wrote: > > On 5/7/12 5:47 AM, James Courtier-Dutton wrote: > >> > >> Hi, > >> > >> I am writing a decompiler. I was wondering if some of LLVM could be > >> used for a

On 5/7/12 5:47 AM, James Courtier-Dutton wrote: > Hi, > > I am writing a decompiler. I was wondering if some of LLVM could be > used for a decompiler. > There are several stages in the decompiler process. > 1) Take binary and create a higher level representation of it. Like RTL. > 2) The output is then broken into blocks or nodes, each block ends in > a CALL, JMP, RET, or

On 3/12/2013 11:55 AM, James Courtier-Dutton wrote: > I already know how to handle the case you describe. > I am not converting ASM to LLVM IR without doing quite a lot of analysis first. > 1) I can already tell if a register is refering to a pointer or an > integer based on how it is used. Does it get de-referenced or not? So, > I would know that "p" is a pointer. What if

Hello, If anyone would like it I have provided a Dovecot 1.0 test61 port and package for FreeBSD 5.3 here. I made them for my own experimentation but thought they might be interesting to others I suppose. http://www.helenmarks.co.uk/~dom/dovecot/ These deviate from the stock test61 because I've updated and added a patch I wrote a long time ago for ioloop kqueue/kevent support in

On 12 March 2013 17:10, Joshua Cranmer 🐧 <Pidgeot18 at gmail.com> wrote: > On 3/12/2013 11:55 AM, James Courtier-Dutton wrote: >> > >> 2) From the binary, I would know if it was for 32bit or 64bit. >> 3) I could then use (1) and (2) to know if "add %rax, 8" is "p = p + >> 1" (64bit long), or "p = p + 2(32bit long)" >> >>

Hi All, AVX-512 introduced the K mask registers and masked operations which make a natural choice for legalizing vectors of i1's. For example, define <8 x i32> @foo(<8 x i32>%a, <8 x i32*> %p) { %r = call <8 x i32> @llvm.masked.gather.v8i32(<8 x i32*> %p, i32 4, <8 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true>,

Hi, I know most compilers go from AST to CFG. I am writing a decompiler, so I was wondering if anyone knew of any documents describing how best to get from CFG to AST. The decompiler project is open source. https://github.com/jcdutton/libbeauty The decompiler already contains a disassembler and a virtual machine resulting in an annotated CFG. It uses information gained from using a virtual

Hi, We're trying out Dovecot to see if it's a good replacement for UW-imapd. It seems to be very slow in opening an mbox file, even after it's been indexed. (I mean way slower than UW) Here's some info on the system: Dovecot-1.0-test61 SuSE 8.1, Linux kernel 2.4 Using NFS to access mail. I've tried turning off mmap, using dotlocking, using fcntl locking (lockd, etc. are

While looking at what llvm writes for this testcase, I noticed that there is one redundant operation in resulting assembly. The second 'cmp' operation there is essentially identical to the first one, with reversed order of arguments. Therefore, it is not needed. This testcase is a simple integer comparison routine, similar to what qsort would take to sort an integer array. I think

Hello Dovecot, Version: dovecot-1.0-test61 OS: FreeBSD 5.3-RELEASE i386 Client: Mozilla Thunderbird 1.0 (on WinXP, FreeBSD & Mac OS X) The maillog entries concerning me: - Jan 30 16:16:37 venus dovecot: imap-login: Login: user [10.6.8.3] Jan 30 16:16:37 venus dovecot: imap-login: couldn't remove filter with kqueue: Bad file descriptor Jan 30 16:16:37 venus dovecot: IMAP(user):

Hi, What does llvm use for testing. The area of testing I am interested in are how to test the accuracy of the assembler/disassembler. So, if you take an IR level instruction. How do you verify that the generated CPU specific instruction is correct? Is there an automated method for this? I wish to implement automated testing on a decompiler I am writing, and thought that the test methods used in