[Qemu-devel] [Bug 1832281] [NEW] tcg bug master / 4.0.0 v8 operation >>> and |=

[manuel baesler]

Public bug reported:

vm guest is linux, executed with tcg
running this Node.js snippet leads to

$ node
> a = undefined
undefined
> a >>> 0
4294967295

host node
$ node
> a = undefined
undefined
> a >>> 0
0

same with |=

node
Welcome to Node.js v12.4.0.
Type ".help" for more information.
> let buffer
undefined
> buffer |= 0
0

vm with tcg:

$ ./out/Release/node --version
v12.4.0
./out/Release/node -e "let buffer; buffer |= 0; console.log(buffer);"
-1

vm guest is debian x86_64 latest release
vm guest is started with ./x86_64-softmmu/qemu-system-x86_64 -vnc :0 -cdrom 
debian-9.9.0-amd64-netinst.iso -m 4G -smp cores=6,threads=1,sockets=1 -nic 
user,hostfwd=tcp:ipv4addr:2233-:22 -cpu qemu64 debian.img

git tag v4.0.0 and master, commit
a578cdfbdd8f9beff5ced52b7826ddb1669abbbf, for building qemu-system-
x86_64 was used.

Node.js is compiled on the vm guest (v12.4.0 / master)

see also
https://github.com/nodejs/node/issues/19348#issuecomment-500465502

I need further assistance to track down the cause of the bug.

Kind regards
Manuel

** Affects: qemu
     Importance: Undecided
         Status: New

** Description changed:

  vm guest is linux, executed with tcg
  running this Node.js snippet leads to
  
  $ node
- > a = undefined 
+ > a = undefined
  undefined
  > a >>> 0
  4294967295
  
  host node
  $ node
  > a = undefined
  undefined
  > a >>> 0
  0
  
  same with |=
  
  node
  Welcome to Node.js v12.4.0.
  Type ".help" for more information.
  > let buffer
  undefined
  > buffer |= 0
  0
  
  vm with tcg:
  
  $ ./out/Release/node --version
  v12.4.0
  ./out/Release/node -e "let buffer; buffer |= 0; console.log(buffer);"
  -1
  
- 
  vm guest is debian x86_64 latest release
  vm guest is started with ./x86_64-softmmu/qemu-system-x86_64 -vnc :0 -cdrom 
debian-9.9.0-amd64-netinst.iso -m 4G -smp cores=6,threads=1,sockets=1 -nic 
user,hostfwd=tcp:ipv4addr:2233-:22 -cpu qemu64 debian.img
  
  git tag v4.0.0 and master, commit
  a578cdfbdd8f9beff5ced52b7826ddb1669abbbf, for building qemu-system-
  x86_64 was used.
  
- Node.js as compiled on the vm guest (v12.4.0 / master)
- 
+ Node.js is compiled on the vm guest (v12.4.0 / master)
  
  see also
  https://github.com/nodejs/node/issues/19348#issuecomment-500465502
  
  I need further assistance to track down the cause of the bug.
  
  Kind regards
  Manuel

-- 
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https://bugs.launchpad.net/bugs/1832281

Title:
  tcg bug master / 4.0.0 v8 operation >>> and |=

Status in QEMU:
  New

Bug description:
  vm guest is linux, executed with tcg
  running this Node.js snippet leads to

  $ node
  > a = undefined
  undefined
  > a >>> 0
  4294967295

  host node
  $ node
  > a = undefined
  undefined
  > a >>> 0
  0

  same with |=

  node
  Welcome to Node.js v12.4.0.
  Type ".help" for more information.
  > let buffer
  undefined
  > buffer |= 0
  0

  vm with tcg:

  $ ./out/Release/node --version
  v12.4.0
  ./out/Release/node -e "let buffer; buffer |= 0; console.log(buffer);"
  -1

  vm guest is debian x86_64 latest release
  vm guest is started with ./x86_64-softmmu/qemu-system-x86_64 -vnc :0 -cdrom 
debian-9.9.0-amd64-netinst.iso -m 4G -smp cores=6,threads=1,sockets=1 -nic 
user,hostfwd=tcp:ipv4addr:2233-:22 -cpu qemu64 debian.img

  git tag v4.0.0 and master, commit
  a578cdfbdd8f9beff5ced52b7826ddb1669abbbf, for building qemu-system-
  x86_64 was used.

  Node.js is compiled on the vm guest (v12.4.0 / master)

  see also
  https://github.com/nodejs/node/issues/19348#issuecomment-500465502

  I need further assistance to track down the cause of the bug.

  Kind regards
  Manuel

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