diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 42d2985d535..ca160d163a2 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -140,6 +140,11 @@ AC_CACHE_CHECK([type of operating system we're going to host on],
     llvm_cv_no_link_all_option="-Wl,--no-whole-archive"
     llvm_cv_os_type="NetBSD"
     llvm_cv_platform_type="Unix" ;;
+  *-*-dragonfly*)
+    llvm_cv_link_all_option="-Wl,--whole-archive"
+    llvm_cv_no_link_all_option="-Wl,--no-whole-archive"
+    llvm_cv_os_type="DragonFly"
+    llvm_cv_platform_type="Unix" ;;
   *-*-hpux*)
     llvm_cv_link_all_option="-Wl,--whole-archive"
     llvm_cv_no_link_all_option="-Wl,--no-whole-archive"
diff --git a/configure b/configure
index adbb5659906..eaf6e1575b3 100755
--- a/configure
+++ b/configure
@@ -2287,6 +2287,11 @@ else
     llvm_cv_no_link_all_option="-Wl,--no-whole-archive"
     llvm_cv_os_type="NetBSD"
     llvm_cv_platform_type="Unix" ;;
+  *-*-dragonfly*)
+    llvm_cv_link_all_option="-Wl,--whole-archive"
+    llvm_cv_no_link_all_option="-Wl,--no-whole-archive"
+    llvm_cv_os_type="DragonFly"
+    llvm_cv_platform_type="Unix" ;;
   *-*-hpux*)
     llvm_cv_link_all_option="-Wl,--whole-archive"
     llvm_cv_no_link_all_option="-Wl,--no-whole-archive"
@@ -10641,7 +10646,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 10644 "configure"
+#line 10649 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -12785,7 +12790,7 @@ ia64-*-hpux*)
   ;;
 *-*-irix6*)
   # Find out which ABI we are using.
-  echo '#line 12788 "configure"' > conftest.$ac_ext
+  echo '#line 12793 "configure"' > conftest.$ac_ext
   if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   (eval $ac_compile) 2>&5
   ac_status=$?
@@ -14503,11 +14508,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:14506: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:14511: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:14510: \$? = $ac_status" >&5
+   echo "$as_me:14515: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -14771,11 +14776,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:14774: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:14779: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:14778: \$? = $ac_status" >&5
+   echo "$as_me:14783: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -14875,11 +14880,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:14878: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:14883: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:14882: \$? = $ac_status" >&5
+   echo "$as_me:14887: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -17327,7 +17332,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 17330 "configure"
+#line 17335 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -17427,7 +17432,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 17430 "configure"
+#line 17435 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -19795,11 +19800,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:19798: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:19803: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:19802: \$? = $ac_status" >&5
+   echo "$as_me:19807: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -19899,11 +19904,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:19902: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:19907: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:19906: \$? = $ac_status" >&5
+   echo "$as_me:19911: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -21469,11 +21474,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:21472: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:21477: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:21476: \$? = $ac_status" >&5
+   echo "$as_me:21481: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -21573,11 +21578,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:21576: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:21581: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:21580: \$? = $ac_status" >&5
+   echo "$as_me:21585: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -23808,11 +23813,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:23811: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:23816: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:23815: \$? = $ac_status" >&5
+   echo "$as_me:23820: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -24076,11 +24081,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:24079: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:24084: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:24083: \$? = $ac_status" >&5
+   echo "$as_me:24088: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -24180,11 +24185,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:24183: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:24188: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:24187: \$? = $ac_status" >&5
+   echo "$as_me:24192: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
diff --git a/lib/System/Mutex.cpp b/lib/System/Mutex.cpp
index 81dcd3b418b..f55dd3fe26f 100644
--- a/lib/System/Mutex.cpp
+++ b/lib/System/Mutex.cpp
@@ -75,7 +75,7 @@ Mutex::Mutex( bool recursive)
     errorcode = pthread_mutexattr_settype(&attr, kind);
     assert(errorcode == 0);
 
-#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
+#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__DragonFly__)
     // Make it a process local mutex
     errorcode = pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_PRIVATE);
 #endif
diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index 2e9902d2e3b..71895f4cbbd 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -1415,7 +1415,7 @@ static void generateCompilerSpecificCode(std::ostream& Out,
       << "extern void *__builtin_alloca(unsigned int);\n"
       << "#endif\n"
       << "#define alloca(x) __builtin_alloca(x)\n"
-      << "#elif defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__)\n"
+      << "#elif defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)\n"
       << "#define alloca(x) __builtin_alloca(x)\n"
       << "#elif defined(_MSC_VER)\n"
       << "#define inline _inline\n"
diff --git a/test/FrontendC/extern-weak.c b/test/FrontendC/extern-weak.c
index 2a8569ca781..f31a6ad0dc7 100644
--- a/test/FrontendC/extern-weak.c
+++ b/test/FrontendC/extern-weak.c
@@ -2,7 +2,7 @@
 // RUN: %llvmgcc -O3 -S -o - -emit-llvm %s | llvm-as | llc
 
 #if !defined(__linux__) && !defined(__FreeBSD__) && \
-    !defined(__OpenBSD__) && !defined(__CYGWIN__)
+    !defined(__OpenBSD__) && !defined(__CYGWIN__) && !defined(__DragonFly__)
 void foo() __attribute__((weak_import));
 #else
 void foo() __attribute__((weak));