similar to: varargs, the x86, and clang

Hi Xiang, On Wed, Nov 11, 2020 at 1:59 AM Zhang, Xiang1 <xiang1.zhang at intel.com> wrote: > Jeremy wrote: > > ... The value %0 is live up to and including the ADD64ri but not past it, meaning LLVM today will drop the DBG_VALUE ... > > Just a little puzzle about the " drop the DBG_VALUE ", maybe I didn't get your key point, >

I'm working on the across the subprogram call optimization, and let's say the following llvm IR, @ng0 = internal global [2 x i32] [i32 2, i32 0], align 4 %t7 = alloca [16 x i8], align 16 %add.ptr = getelementptr inbounds i8* %t1, i64 40 %call = call i8* @handle_value(i8* %add.ptr, i32 3) #3 %arraydecay = getelementptr inbounds [8 x i8]* %t3, i64 0, i64 0 %arraydecay1 =

The PowerPC backend on PPC64 for non-Darwin (SVR4 ABI) systems currently has a problem handling integer types smaller than 64 bits. This is because the ABI specifies that these types are zero-extended to 64 bits on the stack and the default logic provided in LegalizeDAG does not use that convention. Specifically, for these targets we have: setOperationAction(ISD::VAARG, MVT::Other, Expand);

On Fri, 23 Mar 2012 09:50:12 +0100 Ivan Llopard <ivanllopard at gmail.com> wrote: > Hi Finkel, > > Le 23/03/2012 05:50, Hal Finkel a écrit : > > The PowerPC backend on PPC64 for non-Darwin (SVR4 ABI) systems > > currently has a problem handling integer types smaller than 64 bits. > > This is because the ABI specifies that these types are > > zero-extended

Le 23/03/2012 17:02, Hal Finkel a écrit : > On Fri, 23 Mar 2012 09:50:12 +0100 > Ivan Llopard<ivanllopard at gmail.com> wrote: > >> Hi Finkel, >> >> Le 23/03/2012 05:50, Hal Finkel a écrit : >>> The PowerPC backend on PPC64 for non-Darwin (SVR4 ABI) systems >>> currently has a problem handling integer types smaller than 64 bits. >>> This

Hi Finkel, Le 23/03/2012 05:50, Hal Finkel a écrit : > The PowerPC backend on PPC64 for non-Darwin (SVR4 ABI) systems > currently has a problem handling integer types smaller than 64 bits. > This is because the ABI specifies that these types are zero-extended to > 64 bits on the stack and the default logic provided in LegalizeDAG does > not use that convention. Specifically, for

Hi everyone, I'm implementing varags handling for PPC32 with the ELF ABI. It is largely more complicated than the Macho ABI or x86 because it manipulates a struct instead of a direct pointer in the stack. You can find the layout of the va_list struct at the end of this mail. A VAARG call requires a lot of computation. Typically the C code for va_arg(ap, int) is: int va_arg_gpr(ap_list

On Tue, 3 Apr 2007, Nicolas Geoffray wrote: > A VAARG call requires a lot of computation. Typically the C code for > va_arg(ap, int) If you use va_arg in C, are you seeing llvm.vaarg in the output .ll file? -Chris > is: > > int va_arg_gpr(ap_list ap) { > int idx = ap->gpr; > if (idx < 8) { > ap->gpr = idx + 1; > return

Hi Chris, Chris Lattner wrote: > On Tue, 3 Apr 2007, Nicolas Geoffray wrote: > >> A VAARG call requires a lot of computation. Typically the C code for >> va_arg(ap, int) >> > > If you use va_arg in C, are you seeing llvm.vaarg in the output .ll file? > I'm guessing that if you're asking, then no llvm.vaarg is generated. I can not test it on my

Hi Andrew, Andrew Lenharth wrote: > On 4/2/07, Nicolas Geoffray <nicolas.geoffray at lip6.fr> wrote: > >> Hi everyone, >> >> Currently, when declaring a va_list in llvm, one only needs to do: >> >> %ap = alloca i8 * (Reference : llvm/docs/LangRef.html#int_varargs) >> > > This example is x86 specific. alpha allocas an {sbyte*, int}

I'm generating code for a target that only supports i32 natively. My front end is generating VAARG for accessing varargs parameters. The problem is that I get an assert when I compile this: #include <stdarg.h> int main(va_list ap) { typedef double type; type tmp; tmp = va_arg(ap, type); } Bitcode: ; ModuleID = 't0056.bc' target datalayout =

Hello, Everyone > On this specific case, IIRC, MinGW chokes if asmprinter is not on the > list of components. This may be another consequence of the malfunctoning > of llvm-config/GenLibDeps.pl on MinGW/MSYS. This works for me without any problems on mingw32. What are the problems you're seeing? -- WBR, Anton Korobeynikov

Hi everyone, Currently, when declaring a va_list in llvm, one only needs to do: %ap = alloca i8 * (Reference : llvm/docs/LangRef.html#int_varargs) This is OK for x86 and PPC/Darwin ABI because a va_list in these architectures is just a pointer to the stack. The va_start intrinsic just initializes where the pointer points at in the stack. I do not know how the other backends operate, but I

On 4/2/07, Nicolas Geoffray <nicolas.geoffray at lip6.fr> wrote: > Hi everyone, > > Currently, when declaring a va_list in llvm, one only needs to do: > > %ap = alloca i8 * (Reference : llvm/docs/LangRef.html#int_varargs) This example is x86 specific. alpha allocas an {sbyte*, int} (and does so in llvm-gcc). What the type of the alloca to use is requires the frontend to

Hello, LLVMers! How can I force a front end to generate VAARG for accessing varargs parameters? I compile a simple C-code: #include <stdarg.h> int FnVarArgs(int a, ...) { int i,tmp=0; va_list ptArgument; va_start(ptArgument,a); for(i=0;i<9;i++) tmp+= va_arg(ptArgument,int); return tmp; } And then have this bytecode: ; ModuleID = 'main.bc' target

# The future of the va_arg instruction ## Summary LLVM IR currently defines a va_arg instruction, which can be used to access a vararg. Few Clang targets make use of it, and it has a number of limitations. This RFC hopes to promote discussion on its future - how 'smart' should va_arg be? Should we be aiming to transition all targets and LLVM frontends to using it? ## Background on va_arg

FWIW, attached is a similar patch that adds a -falways-use-llvm-vaarg flag to Clang. Applies against mainline. (As discussed, va_arg isn't really supported well so this probably doesn't work well on anything other than simple code, YMMV, etc) ~Will On Thu, May 12, 2011 at 12:29 PM, Arushi Aggarwal <arushi987 at gmail.com> wrote: > Have these changes made it to mainline? Is

Oh, no. I should have been more clear. The patch was not rejected, just lost in the daily shuffle. I already have my employer's approval to send this upstream, so I will prepare a patch against trunk this morning. > I proposed a similar patch to LLVM (left circular shift) around 10/2011. > > Parts of my patch did make it into trunk about a year after, but others > > did not.

... can *any* instruction(s) other than load and store cause memory reads or writes? This is pretty important, because I need to be able to track (at least) writes, and ideally also reads in order to be able to make explicit-state model checking work efficiently. (I don't really care about reads or writes to spilled registers added by the code generator). Sarah

Such as printf, etc., from IR created using the API (IRBuilder). Google hasn't provided much help, and I can't find anything relevant in the docs (the docs talk about how to do varargs in LLVM ASM, but not how to call an external vararg function that exists in a library that gets linked to the LLVM module). Is there something special I need to do? Simply calling