Unable to compile with GCC 4.8

[eleshar]

Hi,

I'm attempting to install the latest release as outlined on https://developers.google.com/speed/pagespeed/module/build_ngx_pagespeed_from_source but my installation keeps failing with:

In file included from /root/sources/ngx_pagespeed/psol/include/third_party/chromium/src/base/logging.h:14:0,
from /root/sources/ngx_pagespeed/src/log_message_handler.cc:30:
/root/sources/ngx_pagespeed/psol/include/third_party/chromium/src/base/basictypes.h: In function âDest bit_cast(const Source&)â:
/root/sources/ngx_pagespeed/psol/include/third_party/chromium/src/base/basictypes.h:318:16: error: typedef âVerifySizesAreEqualâ locally defined but not used [-Werror=unused-local-typedefs]
typedef char VerifySizesAreEqual [sizeof(Dest) == sizeof(Source) ? 1 : -1];
^
cc1plus: all warnings being treated as errors
make[1]: *** [objs/addon/src/log_message_handler.o] Error 1
make[1]: Leaving directory `/root/sources/nginx-1.5.2'
make: *** [install] Error 2

I'm on Ubuntu 13.04 and building with:
./configure --prefix=/opt/nginx --conf-path=/etc/nginx/nginx.conf --pid-path=/var/run/nginx.pid --lock-path=/var/lock/nginx.lock --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --http-client-body-temp-path=/var/lib/nginx/body --http-proxy-temp-path=/var/lib/nginx/proxy --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --http-scgi-temp-path=/var/lib/nginx/scgi --with-http_stub_status_module --with-http_ssl_module --with-http_realip_module --with-http_gzip_static_module --user=www-data --group=www-data --with-debug --without-mail_pop3_module --without-mail_imap_module --without-mail_smtp_module --add-module=/root/sources/ngx_pagespeed-release-1.6.29.3-beta --with-http_spdy_module

[chaizhenhua]

@eleshar can you follow the instruction here https://github.com/pagespeed/ngx_pagespeed/wiki/Building-PSOL-From-Source with tag name 1.6.29.2 instead of 1.5.27.3

[jeffkaufman]

I don't think building from source as @chaizhenhua will help, sorry!

The problem is that -Wall in gcc 4.8 now enables -Wunused-local-typedefs and one of our dependencies fails that test.

We either need to fix the dependency or figure out how to build with that warning disabled.

[eleshar]

Thanks @jeffkaufman downgrading gcc to version 4.7.3 resolved the issue.

[jeffkaufman]

With gcc 4.8 I needed to add -Wno-unused-local-typedefs to CFLAGS:

diff --git a/config b/config
index 05e06d2..2505a60 100644
--- a/config
+++ b/config
@@ -87,6 +87,11 @@ fi
 # linker errors, so disable it here.
 CFLAGS="$CFLAGS -DSERF_HTTPS_FETCHING=0"

+# On GCC 4.8 and above, -Wall enables -Wunused-local-typedefs.  This breaks on
+# VerifySizesAreEqual in bit_cast in chromium/src/base/basictypes.h which has a
+# typedef that is intentionally unused.
+CFLAGS="$CFLAGS -Wno-unused-local-typedefs"
+
 pagespeed_include="\
   $mod_pagespeed_dir \
   $mod_pagespeed_dir/third_party/chromium/src \

While this got past the error with VerifySizesAreEqual it gave a new set of errors:

In file included from /home/jefftk/ngx_ps/ngx_pagespeed/psol/include/third_party/chromium/src/base/memory/scoped_ptr.h:100:0,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/psol/include/pagespeed/kernel/base/scoped_ptr.h:26,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/psol/include/net/instaweb/util/public/scoped_ptr.h:23,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/psol/include/net/instaweb/http/public/headers.h:22,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/psol/include/net/instaweb/http/public/response_headers.h:21,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/src/ngx_pagespeed.h:37,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/src/ngx_base_fetch.h:46,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/src/ngx_base_fetch.cc:19:
/home/jefftk/ngx_ps/ngx_pagespeed/psol/include/third_party/chromium/src/base/memory/scoped_ptr.h:134:29: error: invalid use of incomplete type ‘class scoped_ptr<C>’ [-Werror]
   MOVE_ONLY_TYPE_FOR_CPP_03(scoped_ptr, RValue)
                             ^
/home/jefftk/ngx_ps/ngx_pagespeed/psol/include/third_party/chromium/src/base/move.h:198:31: note: in definition of macro ‘MOVE_ONLY_TYPE_FOR_CPP_03’
   struct rvalue_type : public type { \
                               ^
In file included from /home/jefftk/ngx_ps/ngx_pagespeed/psol/include/pagespeed/kernel/base/scoped_ptr.h:26:0,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/psol/include/net/instaweb/util/public/scoped_ptr.h:23,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/psol/include/net/instaweb/http/public/headers.h:22,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/psol/include/net/instaweb/http/public/response_headers.h:21,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/src/ngx_pagespeed.h:37,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/src/ngx_base_fetch.h:46,
                 from /home/jefftk/ngx_ps/ngx_pagespeed/src/ngx_base_fetch.cc:19:
/home/jefftk/ngx_ps/ngx_pagespeed/psol/include/third_party/chromium/src/base/memory/scoped_ptr.h:133:7: error: declaration of ‘class scoped_ptr<C>’ [-Werror]
 class scoped_ptr {

[rbu]

WebKit has this fixed, what about updating this code copy?

[rcarl01]

Is there any update? as it mentioned that Webkit has this fixed!

please share the info

[jlporter]

There is a discussion on the gcc mailing list about this at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54055. I haven't tried, but looking at the trunk version of scoped_ptr.h in chromium, I don't think this has been fixed there yet.

For now, it looks like the only way to continue is disabling treating warnings as errors, since there isn't an option to disable just that warning. Together with Jeff's change, the following diff compiles for me now.

diff --git a/config b/config
index c523aaa..9dac721 100644
--- a/config
+++ b/config
@@ -93,6 +93,19 @@ fi
 # linker errors, so disable it here.
 CFLAGS="$CFLAGS -DSERF_HTTPS_FETCHING=0 $FLAG_MARCH"

+# On GCC 4.8 and above, -Wall enables -Wunused-local-typedefs.  This breaks on
+# VerifySizesAreEqual in bit_cast in chromium/src/base/basictypes.h which has a
+# typedef that is intentionally unused.
+CFLAGS="$CFLAGS -Wno-unused-local-typedefs"
+
+# On GCC 4.8 and above, we get the following compiler warning:
+# chromium/src/base/memory/scoped_ptr.h:133:7: warning: declaration of ‘class scoped_ptr<C>’ [enabled by default]
+# Based on discussion at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54055, this
+# is invalid code, but hasn't been fixed yet in chromium. Unfortunately, there
+# also does not appear to be a flag for just disabling that warning, so we add
+# Wno-error to override nginx's default -Werror option.
+CFLAGS="$CFLAGS -Wno-error"
+
 pagespeed_include="\
   $mod_pagespeed_dir \
   $mod_pagespeed_dir/third_party/chromium/src \

[jeffkaufman]

Thanks for looking into this!

Can we do these relaxations only for gcc 4.8? Something like:

if [ $(gcc --version | head -n 1 | awk '{print $NF}') \> '4.8' ]; then
  # comments
  CFLAGS="$CFLAGS -Wno-unused-local-typedefs"
  # comments
  CFLAGS="$CFLAGS -Wno-error"
fi

[jlporter]

That didn't quite work on my system. Looks like there is some variability in the gcc version strings.

$ gcc --version
gcc (GCC) 4.8.1 20130725 (prerelease)
$ gcc --version | head -n 1 | awk '{print $NF}'                                                                                            
(prerelease)

I came up with the following based on nginx's auto/cc/gcc

diff --git a/config b/config
index c523aaa..11ac24b 100644
--- a/config
+++ b/config
@@ -93,6 +93,23 @@ fi
 # linker errors, so disable it here.
 CFLAGS="$CFLAGS -DSERF_HTTPS_FETCHING=0 $FLAG_MARCH"

+case "$NGX_GCC_VER" in
+  4.8*)
+    # On GCC 4.8 and above, -Wall enables -Wunused-local-typedefs.  This breaks on
+    # VerifySizesAreEqual in bit_cast in chromium/src/base/basictypes.h which has a
+    # typedef that is intentionally unused.
+    CFLAGS="$CFLAGS -Wno-unused-local-typedefs"
+
+    # On GCC 4.8 and above, we get the following compiler warning:
+    # chromium/src/base/memory/scoped_ptr.h:133:7: warning: declaration of ‘class scoped_ptr<C>’ [enabled by default]
+    # Based on discussion at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54055, this
+    # is invalid code, but hasn't been fixed yet in chromium. Unfortunately, there
+    # also does not appear to be a flag for just disabling that warning, so we add
+    # Wno-error to override nginx's default -Werror option.
+    CFLAGS="$CFLAGS -Wno-error"
+  ;;
+esac
+
 pagespeed_include="\
   $mod_pagespeed_dir \
   $mod_pagespeed_dir/third_party/chromium/src \

[jeffkaufman]

That is so much better; thanks!

Do you want to create the pull request or should I?

[jeffkaufman]

Fixed by #528