[commit: ghc] master: libdw: More precise version check (e9ad489)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/e9ad48935fa48aa32dc39a55512168ba5f5bdbd2/ghc

>---------------------------------------------------------------

commit e9ad48935fa48aa32dc39a55512168ba5f5bdbd2
Author: Ben Gamari <bgamari.foss at gmail.com>
Date:   Fri Apr 15 11:43:41 2016 +0200

    libdw: More precise version check
    
    Test Plan: Try configure in an environment with older `libdw`
    
    Reviewers: hvr, austin
    
    Subscribers: thomie, erikd
    
    Differential Revision: https://phabricator.haskell.org/D2103
    
    GHC Trac Issues: #11820


>---------------------------------------------------------------

e9ad48935fa48aa32dc39a55512168ba5f5bdbd2
 configure.ac            |  9 ++++++++-
 distrib/configure.ac.in | 10 ++++++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index ff717a1..dd3236c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1052,7 +1052,14 @@ if test "$use_large_address_space" = "yes" ; then
    AC_DEFINE([USE_LARGE_ADDRESS_SPACE], [1], [Enable single heap address space support])
 fi
 
-AC_CHECK_LIB(dw, dwfl_begin, [HaveLibdw=YES], [HaveLibdw=NO])
+dnl ** Have libdw?
+dnl --------------------------------------------------------------
+AC_ARG_ENABLE(libdw,
+    [AC_HELP_STRING([--enable-dwarf-unwind],
+        [Enable DWARF unwinding support in the runtime system via elfutils' libdw [default=no]])],
+    [AC_CHECK_LIB(dw, dwfl_attach_state, [HaveLibdw=YES], [HaveLibdw=NO])],
+    [HaveLibdw=NO]
+)
 AC_SUBST(HaveLibdw)
 
 if test -n "$SPHINXBUILD"; then
diff --git a/distrib/configure.ac.in b/distrib/configure.ac.in
index 1df58d5..c0610c6 100644
--- a/distrib/configure.ac.in
+++ b/distrib/configure.ac.in
@@ -93,8 +93,14 @@ AC_SUBST([LdCmd])
 
 dnl ** Have libdw?
 dnl --------------------------------------------------------------
-AC_CHECK_LIB(dw, dwfl_begin, [HaveLibdw=YES], [HaveLibdw=NO])
-AC_SUBST(HaveLibdw)
+dnl Check for a usable version of libdw/elfutils
+dnl Currently we need 0.158 or newer.
+BinDistNeedsLibdw=@HaveLibdw@
+if test "x$BinDistNeedsLibdw" = "xyes" ; then
+    AC_CHECK_LIB(dw, dwfl_attach_state, [HaveLibdw=YES],
+        [AC_MSG_ERROR([Binary distribution was built with libdw support but target system doesn't have supported libdw version (needs at least 0.158)])]
+    )];
+fi
 
 FP_GCC_VERSION
 AC_PROG_CPP