similar to: [LLVMdev] LLVM disassembler bugs

The attached patch includes no test-case and isn't consistent with the rest of the file: - constants should be on the right hand side of comparisons - the braces around your single line 'if' aren't needed. On Sun, Sep 15, 2013 at 2:39 PM, James Courtier-Dutton < james.dutton at gmail.com> wrote: > I attach a patch that fixes this bug. Applies to llvm 3.4svn > >

I attach a patch that fixes this bug. Applies to llvm 3.4svn Please commit it please. Kind Regards James On 13 September 2013 17:46, James Courtier-Dutton <james.dutton at gmail.com>wrote: > Hi, > > I am looking at the "LLVMOpInfoCallback GetOpInfo" callback. > > Example 1 GOOD: > 41 c6 84 24 16 04 00 00 0c : movb $12, 1046(%r12) > > Makes

Test case attached. It is not a test case that works within the llvm test-suite yet, but it does demonstrate the problem. I would like some advice on how to modify this test_case so that it can be added to the automated llvm test cases. On 15 September 2013 23:02, David Majnemer <david.majnemer at gmail.com> wrote: > The attached patch includes no test-case and isn't consistent

On Mon, 6 May 2019 at 10:13, James Courtier-Dutton via llvm-dev <llvm-dev at lists.llvm.org> wrote: > Although the above is mentioning bytes, looking at the "/ 8" and "& 0x7" makes it look like the author meant octets and not bytes. > Bytes can be any size of bits. I don't think you'll have much luck trying to make that stick for a general audience,

Hi, I am looking for an IR that is similar to LLVM IR, with its SSA form, module->function->block->instruction etc. But, I wish a much reduced type model. I wish only three types: 1) An Integer of various bit-widths. 2) A pointer, but a pointer that does not need to point to a known type. A sort of "pointer to unknown type". 3) Floats of various varieties. For example, if we

Hi, By way of example, I have the following instruction: 44 8b 80 c8 03 00 00 movl 968(%rax), %r8d 1) How is this represented in MCInst? 2) Is there information in MCInst that would tell me which bytes of the instruction are responsible for the 968? The reason I am asking is that I want to work with the bytes disassembled/decoded to an instruction at MCInst level.

On Mon, 2019-05-06 at 15:56 -0700, Philip Reames via llvm-dev wrote: > > > On 5/6/19 2:43 AM, Tim Northover via llvm-dev wrote: > > On Mon, 6 May 2019 at 10:13, James Courtier-Dutton via llvm-dev > > <llvm-dev at lists.llvm.org> wrote: > > > Although the above is mentioning bytes, looking at the "/ > > > 8" and "& 0x7" makes

Hi, I think this is a very simple question, and it must just be missing something. I am looking for find out how to assign a constant integer value to the variable in llvm ir. The following returns 12, and %var2 = 12. ; ModuleID = 't.c' target datalayout =

On Mar 15, 2013 10:53 PM, "Óscar Fuentes" <ofv at wanadoo.es> wrote: > > James Courtier-Dutton <james.dutton at gmail.com> writes: > > > I think this is a very simple question, and it must just be missing something. > > > > I am looking for find out how to assign a constant integer value to > > the variable in llvm ir. > > > > The

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 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, 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

On Sun, Apr 16, 2017 at 2:34 AM James Courtier-Dutton via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Hi, > > Did this work ever get done? There was a long thread about it back in 2015. > > I wish to use IRBuilder. > Is there any documentation? > How do I use the singular pointer type in GEP, LOAD, STORE instructions? > Sorry, no, the work is not complete - for

On Mon, Oct 28, 2013 at 10:09 AM, James Courtier-Dutton <james.dutton at gmail.com> wrote: > My guess is that this is a missed optimization, but in real life, all > projects i have worked fix this in the C or C++ code using macros that > change what instructions are used based on target platform and its > endedness. One reason for writing code like this, i.e. explicitly spelling

On Thu, Aug 7, 2014 at 7:09 AM, Rafael Espíndola <rafael.espindola at gmail.com> wrote: >> The implementation of llvm-objdump does have a MachODump.cpp for use with the -m option that I could do the a similar hack otool(1) like hack and special case 32-bit ARM cpus. And at least it contains the ugliness. But this does not really help the non -m case and I suspect ELF objects may face

Hi, 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 cleverly removing any branches): 0000000000000000 <test61>: 0: 83 ff 01 cmp $0x1,%edi 3:

Hi, James, Thanks for your reply. I do not think it is always true, that "mul then add" is faster than "add then mul". For example, A small immediate can be directly encoded in the instruction, but it becomes a larger one after a multiplication, which has to be loaded from the constant pool (extra memory access). So I wonder, is it possile to prevent it, via changes

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

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

Hi, I see this in the Type class: unsigned getSubclassData() const { return SubclassData; } void setSubclassData(unsigned val) { SubclassData = val; // Ensure we don't have any accidental truncation. assert(getSubclassData() == val && "Subclass data too large for field"); } How will the assert ever get triggered? The type is "unsigned" so how can