compile error ,target=arm7

[solzoc]

I'm trying to compile nodejs v4.1.0 with gcc version 4.8 for arm v7 platform. but I've got an error:

../deps/v8/src/base/lazy-instance.h:96:10: error: field 'T' has incomplete type
struct V8_ALIGNAS(T, 16) StorageType {
       ^

V8_ALIGNAS is defined in deps/v8/include/v8config.h

...
#if V8_HAS_CXX11_ALIGNAS
# define V8_ALIGNAS(type, alignment) alignas(type)
#elif V8_HAS_ATTRIBUTE_ALIGNED
...

[mscdex]

Can you show how you're configuring and building (specifically what commands)? Additionally, are you cross-compiling or compiling on-device?

[solzoc]

I used script on this post: https://gist.github.com/Gioyik/7895192
And I'm cross-compiling on linux pc.

[bnoordhuis]

It looks like you're hitting a compiler bug, not much we can do about that. See if you can upgrade to g++ 4.9 or 5.1 or try using clang++.

[solzoc]

Thank you for your comment.
gcc 4.8.2 resolves the error .
I guess early 4.8 gcc version might have the problem

[solzoc]

I compiled successfully, but when I download cross-compiled node* to arm board and execute it, I've got error

$ ./node
 Illegal instruction
$

[bnoordhuis]

Does node --noenable_vfp3 work? If so, you may need to configure the FPU. A patch for that landed just yesterday, commit 17665af.

[kvic-z]

Same situation of Illegal Instruction here. Tried with --noenable_vfp3. Any ideas what else to try? My SoC is a Cortex-A9 (Broadcom 4708) without a FPU. Here is the backtrace.

(gdb) run
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /tmp/mnt/sandisk/entware.arm/local/node-v4.2.1/bin/node "--noenable_vfp3"
warning: File "/tmp/mnt/sandisk/entware.arm/lib/libthread_db-1.0.so" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
warning: Unable to find libthread_db matching inferior's thread library, thread debugging will not be available.
[New LWP 4707]
[New LWP 4708]
[New LWP 4709]
[New LWP 4710]

Program received signal SIGILL, Illegal instruction.
0x55e1e284 in ?? ()
(gdb) bt
#0  0x55e1e284 in ?? ()
#1  0x003addb0 in v8::internal::Execution::Call(v8::internal::Isolate*, v8::internal::Handle<v8::internal::Object>, v8::internal::Handle<v8::internal::Object>, int, v8::internal::Handle<v8::internal::Object>*, bool) ()
#2  0x0026a214 in v8::internal::Genesis::CompileNative(v8::internal::Isolate*, v8::internal::Vector<char const>, v8::internal::Handle<v8::internal::String>, int, v8::internal::Handle<v8::internal::Object>*) ()
#3  0x0026ee00 in v8::internal::Genesis::CompileBuiltin(v8::internal::Isolate*, int) ()
#4  0x0027259c in v8::internal::Genesis::InstallNatives() ()
#5  0x002744d4 in v8::internal::Genesis::Genesis(v8::internal::Isolate*, v8::internal::MaybeHandle<v8::internal::JSGlobalProxy>, v8::Local<v8::ObjectTemplate>, v8::ExtensionConfiguration*) ()
#6  0x002748f0 in v8::internal::Bootstrapper::CreateEnvironment(v8::internal::MaybeHandle<v8::internal::JSGlobalProxy>, v8::Local<v8::ObjectTemplate>, v8::ExtensionConfiguration*) ()
#7  0x002426c8 in v8::Context::New(v8::Isolate*, v8::ExtensionConfiguration*, v8::Local<v8::ObjectTemplate>, v8::Local<v8::Value>)
    ()
#8  0x0072c7c4 in node::Start(int, char**) ()
#9  0x402681bc in __libc_start_main () from /opt/lib/libc.so.6
#10 0x00213634 in _start ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

[bnoordhuis]

What does disassemble $pc,$pc+16 print?

PS: I don't think node.js and V8 support nofpu mode as such but I would expect the kernel to emulate floating point instructions.

[kvic-z]

Here you're (thanks for the speedy response btw:)

(gdb) disassemble $pc,$pc+16
Dump of assembler code from 0x3cf1e284 to 0x3cf1e294:
=> 0x3cf1e284:  vpush   {d8-d15}
   0x3cf1e288:  mov r12, #0
   0x3cf1e28c:  vmov    d14, r12, r12
   0x3cf1e290:  vmrs    r4, fpscr
End of assembler dump.

My kernel perhaps doesn't have FPU emulation compiled in. I'll need to check. I compiled node.js+v8 with -mfloat-abi=soft. I thought FPU emulation handled by c/c++ libraries without kernel involvement?

[bnoordhuis]

Right, it looks like emulation is indeed disabled.

I compiled node.js+v8 with -mfloat-abi=soft. I thought FPU emulation handled by c/c++ libraries without kernel involvement?

For C and C++ code, yes. V8 is a JIT compiler however, it generates machine code at run-time, and I'm almost positive it doesn't support FPU-less mode.

[bnoordhuis]

Closing due to inactivity.