[LLVMdev] [NVPTX] Backend cannot handle array-of-arrays constant

[Dmitry N. Mikushin]

I think our test case demonstrates that requiring the array item being
initialized to be constant is incorrect. NVPTX does not crash anymore
and produces correct result with the following change:

--- NVPTXAsmPrinter.cpp	2012-09-03 15:14:00.000000000 +0200
+++ NVPTXAsmPrinter.cpp	2012-09-04 15:47:17.859398193 +0200
@@ -1890,17 +1890,15 @@
   case Type::ArrayTyID:
   case Type::VectorTyID:
   case Type::StructTyID: {
-    if (isa<ConstantArray>(CPV) || isa<ConstantVector>(CPV) ||
-        isa<ConstantStruct>(CPV)) {
+    if (isa<ConstantAggregateZero>(CPV))
+      aggBuffer->addZeros(Bytes);
+    else
+    {
       int ElementSize = TD->getTypeAllocSize(CPV->getType());
       bufferAggregateConstant(CPV, aggBuffer);
       if ( Bytes > ElementSize )
         aggBuffer->addZeros(Bytes-ElementSize);
     }
-    else if (isa<ConstantAggregateZero>(CPV))
-      aggBuffer->addZeros(Bytes);
-    else
-      llvm_unreachable("Unexpected Constant type");
     break;
   }

It it OK, how do you think?

Thanks,
- D.

2012/9/4 Dmitry N. Mikushin <maemarcus at gmail.com>:
> NVCC successfully handles the same IR, if we try to process the same
> .cu file with clang+nvptx and nvcc:
>
> CLANG/NVPTX:
> =============
>
> $ cat dayofweek.cu
> __attribute__((device)) char yweek[7][4] = { "MON", "TUE", "WED",
> "THU", "FRI", "SAT", "SUN" };
> $ clang -cc1 -emit-llvm -fcuda-is-device dayofweek.cu -o dayofweek.ll
> $ cat dayofweek.ll
> ; ModuleID = 'dayofweek.cu'
> target datalayout =
> "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
> target triple = "x86_64-unknown-linux-gnu"
>
> @yweek = global [7 x [4 x i8]] [[4 x i8] c"MON\00", [4 x i8]
> c"TUE\00", [4 x i8] c"WED\00", [4 x i8] c"THU\00", [4 x i8] c"FRI\00",
> [4 x i8] c"SAT\00", [4 x i8] c"SUN\00"], align 16
> $ llc -march="nvptx" dayofweek.ll -o -
> //
> // Generated by LLVM NVPTX Back-End
> //
>
> .version 3.0
> .target sm_10, texmode_independent
> .address_size 32
>
> Unexpected Constant type
> UNREACHABLE executed at
> /home/marcusmae/rpmbuild/BUILD/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp:1903!
>
> NVCC
> =====
>
> $ nvcc -c -keep dayofweek.cu
> $ cat dayofweek.ptx
>
>         .global .align 1 .b8 yweek[28] =
> {0x4d,0x4f,0x4e,0x0,0x54,0x55,0x45,0x0,0x57,0x45,0x44,0x0,0x54,0x48,0x55,0x0,0x46,0x52,0x49,0x0,0x53,0x41,0x54,0x0,0x53,0x55,0x4e,0x0};
>
> 2012/9/3 Dmitry N. Mikushin <maemarcus at gmail.com>:
>> Dear all,
>>
>> Looks like the NVPTX backend cannot handle array-of-arrays contant
>> (please see the reporocase below). Is it supposed to work? Any ideas
>> how to get it working? Important for our target applications.
>>
>> Thanks,
>> - Dima.
>>
>> $ cat test.ll
>> ; ModuleID = '__kernelgen_main_module'
>> target datalayout =
>> "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v16:16:16-v32:32:32-v64:64:64-v128:128:128-n16:32:64"
>> target triple = "nvptx64-unknown-unknown"
>>
>> @yweek.1533 = internal global [7 x [3 x i8]] [[3 x i8] c"MON", [3 x
>> i8] c"TUE", [3 x i8] c"WED", [3 x i8] c"THU", [3 x i8] c"FRI", [3 x
>> i8] c"SAT", [3 x i8] c"SUN"], align 4096
>>
>> $ llc -march="nvptx" test.ll -o -
>> //
>> // Generated by LLVM NVPTX Back-End
>> //
>>
>> .version 3.0
>> .target sm_10, texmode_independent
>> .address_size 32
>>
>> Unexpected Constant type
>> UNREACHABLE executed at
>> /home/marcusmae/rpmbuild/BUILD/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp:1903!
>> 0  libLLVM-3.2svn.so 0x00007f1bcb71bf0e
>> 1  libLLVM-3.2svn.so 0x00007f1bcb71bd0a
>> 2  libpthread.so.0   0x00007f1bca33ccb0
>> 3  libc.so.6         0x00007f1bc9aa8445 gsignal + 53
>> 4  libc.so.6         0x00007f1bc9aabbab abort + 379
>> 5  libLLVM-3.2svn.so 0x00007f1bcb7044a3
>> 6  libLLVM-3.2svn.so 0x00007f1bcb3e6396
>> 7  libLLVM-3.2svn.so 0x00007f1bcb3e6494
>> 8  libLLVM-3.2svn.so 0x00007f1bcb3e39fe
>> 9  libLLVM-3.2svn.so 0x00007f1bcb3e23e8
>> 10 libLLVM-3.2svn.so 0x00007f1bcb1a90a1
>> llvm::FPPassManager::doInitialization(llvm::Module&) + 73
>> 11 libLLVM-3.2svn.so 0x00007f1bcb1a8fb0
>> llvm::FPPassManager::runOnModule(llvm::Module&) + 36
>> 12 libLLVM-3.2svn.so 0x00007f1bcb1a9337
>> llvm::MPPassManager::runOnModule(llvm::Module&) + 453
>> 13 libLLVM-3.2svn.so 0x00007f1bcb1a9869
>> llvm::PassManagerImpl::run(llvm::Module&) + 125
>> 14 libLLVM-3.2svn.so 0x00007f1bcb1a9a1d
>> llvm::PassManager::run(llvm::Module&) + 39
>> 15 llc               0x000000000040ed8e main + 3091
>> 16 libc.so.6         0x00007f1bc9a9376d __libc_start_main + 237
>> 17 llc               0x000000000040dac9
>> Stack dump:
>> 0.      Program arguments: llc -march=nvptx test.ll -o -
>> 1.      Running pass 'Function Pass Manager' on module 'test.ll'.
>> Aborted (core dumped)