zfs-patches/0005-Implement-enable-debuginfo-to-force-debuginfo.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Richard Yao <richard.yao@clusterhq.com>
   3 Date: Tue, 23 Sep 2014 14:29:30 -0400
   4 Subject: [PATCH] Implement --enable-debuginfo to force debuginfo
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   8
   9 Inspection of a Ubuntu 14.04 x64 system revealed that the config file
  10 used to build the kernel image differs from the config file used to
  11 build kernel modules by the presence of CONFIG_DEBUG_INFO=y:
  12
  13 This in itself is insufficient to show that the kernel is built with
  14 debuginfo, but a cursory analysis of the debuginfo provided and the
  15 size of the kernel strongly suggests that it was built with
  16 CONFIG_DEBUG_INFO=y while the modules were not. Installing
  17 linux-image-$(uname -r)-dbgsym had no obvious effect on the debuginfo
  18 provided by either the modules or the kernel.
  19
  20 The consequence is that issue reports from distributions such as Ubuntu
  21 and its derivatives build kernel modules without debuginfo contain
  22 nonsensical backtraces. It is therefore desireable to force generation
  23 of debuginfo, so we implement --enable-debuginfo. Since the build system
  24 can build both userspace components and kernel modules, the generic
  25 --enable-debuginfo option will force debuginfo for both. However, it
  26 also supports --enable-debuginfo=kernel and --enable-debuginfo=user for
  27 finer grained control.
  28
  29 Enabling debuginfo for the kernel modules works by injecting
  30 CONFIG_DEBUG_INFO=y into the make environment. This is enables
  31 generation of debuginfo by the kernel build systems on all Linux
  32 kernels, but the build environment is slightly different int hat
  33 CONFIG_DEBUG_INFO has not been in the CPP. Adding -DCONFIG_DEBUG_INFO
  34 would fix that, but it would also cause build failures on kernels where
  35 CONFIG_DEBUG_INFO=y is already set. That would complicate its use in
  36 DKMS environments that support a range of kernels and is therefore
  37 undesireable. We could write a compatibility shim to enable
  38 CONFIG_DEBUG_INFO only when it is explicitly disabled, but we forgo
  39 doing that because it is unnecessary. Nothing in ZoL or the kernel uses
  40 CONFIG_DEBUG_INFO in the CPP at this time and that is unlikely to
  41 change.
  42
  43 Enabling debuginfo for the userspace components is done by injecting -g
  44 into CPPFLAGS. This is not necessary because the build system honors the
  45 environment's CPPFLAGS by appending them to the actual CPPFLAGS used,
  46 but it is supported for consistency.
  47
  48 Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
  49 Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
  50 Signed-off-by: Richard Yao <richard.yao@clusterhq.com>
  51 Closes #2734
  52 (cherry picked from commit 834815e9f767c9c5e7220ff84f29b1f069822a4d)
  53 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  54 ---
  55  configure.ac        |  1 +
  56  config/zfs-build.m4 | 33 ++++++++++++++++++++++++++++++++-
  57  2 files changed, 33 insertions(+), 1 deletion(-)
  58
  59 diff --git a/configure.ac b/configure.ac
  60 index 0c7977ef8..e145aa370 100644
  61 --- a/configure.ac
  62 +++ b/configure.ac
  63 @@ -55,6 +55,7 @@ ZFS_AC_LICENSE
  64  ZFS_AC_PACKAGE
  65  ZFS_AC_CONFIG
  66  ZFS_AC_DEBUG
  67 +ZFS_AC_DEBUGINFO
  68
  69  AC_CONFIG_FILES([
  70         Makefile
  71 diff --git a/config/zfs-build.m4 b/config/zfs-build.m4
  72 index 78a87aef7..a8609b829 100644
  73 --- a/config/zfs-build.m4
  74 +++ b/config/zfs-build.m4
  75 @@ -38,12 +38,43 @@ AC_DEFUN([ZFS_AC_DEBUG], [
  76                 [ZFS_AC_DEBUG_DISABLE],
  77                 [AC_MSG_ERROR([Unknown option $enable_debug])])
  78
  79 -       AC_SUBST(DEBUG_CFLAGS)
  80         AC_SUBST(DEBUG_STACKFLAGS)
  81         AC_SUBST(DEBUG_ZFS)
  82         AC_MSG_RESULT([$enable_debug])
  83  ])
  84
  85 +AC_DEFUN([ZFS_AC_DEBUGINFO_KERNEL], [
  86 +       KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS CONFIG_DEBUG_INFO=y"
  87 +])
  88 +
  89 +AC_DEFUN([ZFS_AC_DEBUGINFO_USER], [
  90 +       DEBUG_CFLAGS="$DEBUG_CFLAGS -g"
  91 +])
  92 +
  93 +AC_DEFUN([ZFS_AC_DEBUGINFO], [
  94 +       AC_MSG_CHECKING([whether debuginfo support will be forced])
  95 +       AC_ARG_ENABLE([debuginfo],
  96 +               [AS_HELP_STRING([--enable-debuginfo],
  97 +               [Force generation of debuginfo @<:@default=no@:>@])],
  98 +               [],
  99 +               [enable_debuginfo=no])
 100 +
 101 +       AS_CASE(["x$enable_debuginfo"],
 102 +               ["xyes"],
 103 +               [ZFS_AC_DEBUGINFO_KERNEL
 104 +               ZFS_AC_DEBUGINFO_USER],
 105 +               ["xkernel"],
 106 +               [ZFS_AC_DEBUGINFO_KERNEL],
 107 +               ["xuser"],
 108 +               [ZFS_AC_DEBUGINFO_USER],
 109 +               ["xno"],
 110 +               [],
 111 +               [AC_MSG_ERROR([Unknown option $enable_debug])])
 112 +
 113 +       AC_SUBST(DEBUG_CFLAGS)
 114 +       AC_MSG_RESULT([$enable_debuginfo])
 115 +])
 116 +
 117  AC_DEFUN([ZFS_AC_CONFIG_ALWAYS], [
 118         ZFS_AC_CONFIG_ALWAYS_NO_UNUSED_BUT_SET_VARIABLE
 119         ZFS_AC_CONFIG_ALWAYS_NO_BOOL_COMPARE
 120 --
 121 2.14.2
 122