1350825 - Printf chops off output - bug in fwrite() call

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement, P1)

Description

[Lars T Hansen [:lth]]

It looks like it prints partial lines, leaves out characters, whatever.  For example:

[Codegen# Emitting wasm code
[Codegen   0333201c
[Codegen   03332020
[Codegen   03332024
[Codegen   03332028
[Codegen# block0 ?:3840206052
[Codegen                        1000
[Codegeninstruction WasmParameter
[Codegeninstruction Integer
[Codegen   0333202c
[Codegeninstruction ShiftI:ursh
[Codegen   03332030
[Codegeninstruction Integer
[Codegen   03332034
[Codegeninstruction ModI
[Codegen   03332038
[Codegen   0333203c
[Codegen   03332040
[Codegen   03332044
[Codegen   03332048
[Codegen   0333204c

Looks more like a generic printf problem than anything else.

Comment 1

[Lars T Hansen [:lth]]

This is an old bug that incorrectly checks the return value from fwrite() - depending on your point of view, it should compare to the number of objects written, namely 1, not the number of bytes written, n; or, it should reverse the arguments to fwrite so that it is n objects of size 1 each, and comparing to n is correct.

The bug is presumably uncovered by the recent printf rewrite.

Bug in vm/Printer.cpp:444.

Comment 2

[Lars T Hansen [:lth]]

Attachment: bug1350825-fwrite-arg-order.patch

Change the order of arguments to fwrite, and label them.

(Fingering nbp for a review since he wrote/ported the code but really would be nice to just land this asap, so anyone should feel free to jump in...)

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/571ac5ec20ab
get the order of arguments to fwrite right. r=nbp

Comment 4

[Lars T Hansen [:lth]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/571ac5ec20ab70db4e71ec81bdb07dd9b294f572
Bug 1350825 - get the order of arguments to fwrite right. r=nbp

Comment 5

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/571ac5ec20ab