Unimplemented instruction in simarm64?

[mkustermann]

Reproduction:

% tools/build.py -mrelease -asimarm64,x64 runtime_kernel
...

% out/ReleaseX64/dart --dfe=out/ReleaseX64/gen/kernel-service.dart.snapshot --kernel-binaries=out/ReleaseX64 --strong --reify-generic-functions --limit-ints-to-64-bits tests/corelib_2/int_parse_radix_test.dart                 
% echo $?
0

% out/ReleaseSIMARM64/dart --dfe=out/ReleaseSIMARM64/gen/kernel-service.dart.snapshot --kernel-binaries=out/ReleaseSIMARM64 --strong --reify-generic-functions --limit-ints-to-64-bits tests/corelib_2/int_parse_radix_test.dart  
Simulator hit Unimplemented instruction: at 0x7f4239ac13f4, last_pc=0x7f4239ac13f0

sim> 

[alexmarkov]

In debug mode

out/DebugSIMARM64/dart --dfe=out/DebugSIMARM64/gen/kernel-service.dart.snapshot --kernel-binaries=out/DebugSIMARM64 --strong --reify-generic-functions --limit-ints-to-64-bits tests/corelib_2/int_parse_radix_test.dart

It fails with an assertion in the assembler:

../../runtime/vm/compiler/assembler/assembler_arm64.h: 405: error: expected: ((imm & 0xfff) == 0) && (Utils::IsUint(12, imm >> 12))

Call stack:

#2  0x0000000000a78489 in dart::OS::Abort () at ../../runtime/vm/os_linux.cc:379
#3  0x0000000000dadb4b in dart::DynamicAssertionHelper::Fail (this=0x7ffff6738788, 
    format=<optimized out>) at ../../runtime/platform/assert.cc:42
#4  0x0000000000c10ccd in Operand (imm=-2, this=<optimized out>)
    at ../../runtime/vm/compiler/assembler/assembler_arm64.h:405
#5  dart::FlowGraphCompiler::CopyParameters (this=<optimized out>, 
    expect_type_args=<optimized out>, 
    check_arguments=<error reading variable: access outside bounds of object referenced via synthetic pointer>) at ../../runtime/vm/compiler/backend/flow_graph_compiler_arm64.cc:734
#6  0x0000000000c12152 in dart::FlowGraphCompiler::CompileGraph (this=0x7ffff6738a48)
    at ../../runtime/vm/compiler/backend/flow_graph_compiler_arm64.cc:1063
#7  0x0000000000d4a640 in dart::CompileParsedFunctionHelper::Compile (this=<optimized out>, 
    pipeline=0x1de0a20) at ../../runtime/vm/compiler/jit/compiler.cc:1212
#8  0x0000000000d4b864 in dart::CompileFunctionHelper (pipeline=0x1de0a20, function=..., 
    optimized=<optimized out>, osr_id=-1) at ../../runtime/vm/compiler/jit/compiler.cc:1344
#9  0x0000000000d4b1b8 in dart::Compiler::CompileFunction (thread=<optimized out>, function=...)
    at ../../runtime/vm/compiler/jit/compiler.cc:1531
#10 0x000000000093bd55 in dart::DartEntry::InvokeFunction (function=..., arguments=..., 
    arguments_descriptor=..., current_sp=140737328161008) at ../../runtime/vm/dart_entry.cc:122
#11 0x0000000000cef645 in dart::kernel::StreamingConstantEvaluator::RunFunction (
    this=0x7ffff673a450, function=..., arguments=..., names=...)
    at ../../runtime/vm/compiler/frontend/kernel_binary_flowgraph.cc:3266
#12 0x0000000000cef4d0 in dart::kernel::StreamingConstantEvaluator::RunFunction (
    this=<optimized out>, function=..., argument_count=<optimized out>, 

Code at flow_graph_compiler_arm64.cc:734

    __ and_(R8, R8,
            Operand(Smi::RawValue(
                ArgumentsDescriptor::PositionalCountField::mask_in_place())));

was added recently in a991c17.

It looks like the value of the mask is not a valid 12-bit immediate.

/cc @sjindel-google