[PATCH] D120958: [TableGen] Add support for variable length instruction in decoder generator

[Min-Yih Hsu via Phabricator via llvm-commits]

myhsu added a comment.

In D120958#3488799 <https://reviews.llvm.org/D120958#3488799>, @gregmiller wrote:

> Hello,  We are maintaining a downstream version of the monorepo based on the LLVM main branch. In a recent attempt to merge the latest upstream commits 
> into our monorepo we came across the following test failures after your commit.
> Any help would be greatly appreciated.
> Thanks
> Greg
>
> --------------------------------------------------------------------------------
>
>   `
>
>
>
>   FAIL: llvm_regressions :: LLVM/TableGen/VarLenDecoder.td
>   --------------------------------------------------------------------------------
>   Script:
>   --
>   : 'RUN: at line 1';   /scratch/gmiller/tools2/llvm_cgt/arm-llvm/RelWithAsserts/llvm/bin/llvm-tblgen -gen-disassembler -I /scratch/gmiller/tools2/llvm_cgt/llvm-project/llvm/test/TableGen/../../include /scratch/gmiller/tools2/llvm_cgt/llvm-project/llvm/test/TableGen/VarLenDecoder.td | /scratch/gmiller/tools2/llvm_cgt/arm-llvm/RelWithAsserts/llvm/bin/FileCheck /scratch/gmiller/tools2/llvm_cgt/llvm-project/llvm/test/TableGen/VarLenDecoder.td
>   --
>   Exit Code: 1
>   
>   Command Output (stderr):
>   --
>   + : 'RUN: at line 1'
>   + /scratch/gmiller/tools2/llvm_cgt/arm-llvm/RelWithAsserts/llvm/bin/llvm-tblgen -gen-disassembler -I /scratch/gmiller/tools2/llvm_cgt/llvm-project/llvm/test/TableGen/../../include /scratch/gmiller/tools2/llvm_cgt/llvm-project/llvm/test/TableGen/VarLenDecoder.td
>   + /scratch/gmiller/tools2/llvm_cgt/arm-llvm/RelWithAsserts/llvm/bin/FileCheck /scratch/gmiller/tools2/llvm_cgt/llvm-project/llvm/test/TableGen/VarLenDecoder.td
>   /scratch/gmiller/tools2/llvm_cgt/llvm-project/llvm/test/TableGen/VarLenDecoder.td:50:16: error: CHECK-NEXT: expected string not found in input
>   // CHECK-NEXT: MCD::OPC_Decode, 244, 1, 0, // Opcode: FOO16
>                  ^
>   <stdin>:72:57: note: scanning from here
>   /* 3 */ MCD::OPC_FilterValue, 8, 4, 0, 0, // Skip to: 12
>                                                           ^
>   <stdin>:73:9: note: possible intended match here
>   /* 8 */ MCD::OPC_Decode, 245, 1, 0, // Opcode: FOO16
>           ^
>   
>   Input file: <stdin>
>   Check file: /scratch/gmiller/tools2/llvm_cgt/llvm-project/llvm/test/TableGen/VarLenDecoder.td
>   
>   -dump-input=help explains the following input dump.
>   
>   Input was:
>   <<<<<<
>              .
>              .
>              .
>             67:  field.insertBits(bits, startBit, numBits); 
>             68: } 
>             69:  
>             70: static const uint8_t DecoderTable43[] = { 
>             71: /* 0 */ MCD::OPC_ExtractField, 3, 5, // Inst{7-3} ... 
>             72: /* 3 */ MCD::OPC_FilterValue, 8, 4, 0, 0, // Skip to: 12 
>   next:50'0                                                             X error: no match found
>             73: /* 8 */ MCD::OPC_Decode, 245, 1, 0, // Opcode: FOO16 
>   next:50'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   next:50'1             ?                                             possible intended match
>             74: /* 12 */ MCD::OPC_FilterValue, 9, 4, 0, 0, // Skip to: 21 
>   next:50'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>             75: /* 17 */ MCD::OPC_Decode, 246, 1, 1, // Opcode: FOO32 
>   next:50'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>             76: /* 21 */ MCD::OPC_Fail, 
>   next:50'0     ~~~~~~~~~~~~~~~~~~~~~~~~
>             77:  0 
>   next:50'0     ~~~
>             78: }; 
>   next:50'0     ~~~
>              .
>              .
>              .
>   >>>>>>
>   
>   --
>   `
>
>   

Looks like the opcode of FOO16 and FOO32 are off by one. I think the number of pseudo opcodes is different (from the upstream one). Are `include/llvm/Support/TargetOpcodes.def` or `include/llvm/Target/Target.td` in your downstream repo different from upstream?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D120958/new/

https://reviews.llvm.org/D120958