From 2a378e99b54c06c6cc19d80d16961154031ff0bf Mon Sep 17 00:00:00 2001
From: Mike Hommey <mh+mozilla@glandium.org>
Date: Fri, 26 Sep 2014 07:33:56 +0900
Subject: [PATCH] Bug 857628 - Add a --enable-pie configure option to build
 target programs as position independent executables when supported by
 gcc/clang. r=mshal

---
 build/autoconf/compiler-opts.m4 | 28 ++++++++++++++++++++++++++++
 config/rules.mk                 | 10 ++++++----
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/build/autoconf/compiler-opts.m4 b/build/autoconf/compiler-opts.m4
index 3322c639ce3..98ecf1e11e4 100644
--- a/build/autoconf/compiler-opts.m4
+++ b/build/autoconf/compiler-opts.m4
@@ -326,6 +326,34 @@ if test "$GNU_CC" -a "$GCC_USE_GNU_LD" -a -z "$DEVELOPER_OPTIONS"; then
         DSO_LDOPTS="$DSO_LDOPTS -Wl,--gc-sections"
     fi
 fi
+
+# bionic in Android < 4.1 doesn't support PIE
+# On OSX, the linker defaults to building PIE programs when targetting OSX 10.7+,
+# but not when targetting OSX < 10.7. OSX < 10.7 doesn't support running PIE
+# programs, so as long as support for OSX 10.6 is kept, we can't build PIE.
+# Even after dropping 10.6 support, MOZ_PIE would not be useful since it's the
+# default (and clang says the -pie option is not used).
+# On other Unix systems, some file managers (Nautilus) can't start PIE programs
+MOZ_PIE=
+
+MOZ_ARG_ENABLE_BOOL(pie,
+[  --enable-pie           Enable Position Independent Executables],
+    MOZ_PIE=1,
+    MOZ_PIE= )
+
+if test "$GNU_CC" -a -n "$MOZ_PIE"; then
+    AC_MSG_CHECKING([for PIE support])
+    _SAVE_LDFLAGS=$LDFLAGS
+    LDFLAGS="$LDFLAGS -pie"
+    AC_TRY_LINK(,,AC_MSG_RESULT([yes])
+                  [MOZ_PROGRAM_LDFLAGS="$MOZ_PROGRAM_LDFLAGS -pie"],
+                  AC_MSG_RESULT([no])
+                  AC_MSG_ERROR([--enable-pie requires PIE support from the linker.]))
+    LDFLAGS=$_SAVE_LDFLAGS
+fi
+
+AC_SUBST(MOZ_PROGRAM_LDFLAGS)
+
 ])
 
 dnl GCC and clang will fail if given an unknown warning option like -Wfoobar. 
diff --git a/config/rules.mk b/config/rules.mk
index 33385626e94..3ce9c5c15f0 100644
--- a/config/rules.mk
+++ b/config/rules.mk
@@ -641,6 +641,8 @@ endif
 
 endif # NO_PROFILE_GUIDED_OPTIMIZE
 
+MOZ_PROGRAM_LDFLAGS += $(MOZ_GLUE_PROGRAM_LDFLAGS)
+
 ##############################################
 
 checkout:
@@ -673,7 +675,7 @@ $(PROGRAM): $(PROGOBJS) $(STATIC_LIBS_DEPS) $(EXTRA_DEPS) $(EXE_DEF_FILE) $(RESF
 	$(REPORT_BUILD)
 	@$(RM) $@.manifest
 ifeq (_WINNT,$(GNU_CC)_$(OS_ARCH))
-	$(EXPAND_LD) -NOLOGO -OUT:$@ -PDB:$(LINK_PDBFILE) $(WIN32_EXE_LDFLAGS) $(LDFLAGS) $(MOZ_GLUE_PROGRAM_LDFLAGS) $(PROGOBJS) $(RESFILE) $(STATIC_LIBS) $(SHARED_LIBS) $(EXTRA_LIBS) $(OS_LIBS)
+	$(EXPAND_LD) -NOLOGO -OUT:$@ -PDB:$(LINK_PDBFILE) $(WIN32_EXE_LDFLAGS) $(LDFLAGS) $(MOZ_PROGRAM_LDFLAGS) $(PROGOBJS) $(RESFILE) $(STATIC_LIBS) $(SHARED_LIBS) $(EXTRA_LIBS) $(OS_LIBS)
 ifdef MSMANIFEST_TOOL
 	@if test -f $@.manifest; then \
 		if test -f '$(srcdir)/$@.manifest'; then \
@@ -694,7 +696,7 @@ ifdef MOZ_PROFILE_GENERATE
 	touch -t `date +%Y%m%d%H%M.%S -d 'now+5seconds'` pgo.relink
 endif
 else # !WINNT || GNU_CC
-	$(EXPAND_CCC) -o $@ $(CXXFLAGS) $(PROGOBJS) $(RESFILE) $(WIN32_EXE_LDFLAGS) $(LDFLAGS) $(WRAP_LDFLAGS) $(STATIC_LIBS) $(MOZ_GLUE_PROGRAM_LDFLAGS) $(SHARED_LIBS) $(EXTRA_LIBS) $(OS_LIBS) $(BIN_FLAGS) $(EXE_DEF_FILE) $(STLPORT_LIBS)
+	$(EXPAND_CCC) -o $@ $(CXXFLAGS) $(PROGOBJS) $(RESFILE) $(WIN32_EXE_LDFLAGS) $(LDFLAGS) $(WRAP_LDFLAGS) $(STATIC_LIBS) $(MOZ_PROGRAM_LDFLAGS) $(SHARED_LIBS) $(EXTRA_LIBS) $(OS_LIBS) $(BIN_FLAGS) $(EXE_DEF_FILE) $(STLPORT_LIBS)
 	$(call CHECK_BINARY,$@)
 endif # WINNT && !GNU_CC
 
@@ -742,7 +744,7 @@ endif
 $(SIMPLE_PROGRAMS): %$(BIN_SUFFIX): %.$(OBJ_SUFFIX) $(STATIC_LIBS_DEPS) $(EXTRA_DEPS) $(GLOBAL_DEPS)
 	$(REPORT_BUILD)
 ifeq (_WINNT,$(GNU_CC)_$(OS_ARCH))
-	$(EXPAND_LD) -nologo -out:$@ -pdb:$(LINK_PDBFILE) $< $(WIN32_EXE_LDFLAGS) $(LDFLAGS) $(MOZ_GLUE_PROGRAM_LDFLAGS) $(STATIC_LIBS) $(SHARED_LIBS) $(EXTRA_LIBS) $(OS_LIBS)
+	$(EXPAND_LD) -nologo -out:$@ -pdb:$(LINK_PDBFILE) $< $(WIN32_EXE_LDFLAGS) $(LDFLAGS) $(MOZ_PROGRAM_LDFLAGS) $(STATIC_LIBS) $(SHARED_LIBS) $(EXTRA_LIBS) $(OS_LIBS)
 ifdef MSMANIFEST_TOOL
 	@if test -f $@.manifest; then \
 		mt.exe -NOLOGO -MANIFEST $@.manifest -OUTPUTRESOURCE:$@\;1; \
@@ -750,7 +752,7 @@ ifdef MSMANIFEST_TOOL
 	fi
 endif	# MSVC with manifest tool
 else
-	$(EXPAND_CCC) $(CXXFLAGS) -o $@ $< $(WIN32_EXE_LDFLAGS) $(LDFLAGS) $(WRAP_LDFLAGS) $(STATIC_LIBS) $(MOZ_GLUE_PROGRAM_LDFLAGS) $(SHARED_LIBS) $(EXTRA_LIBS) $(OS_LIBS) $(BIN_FLAGS) $(STLPORT_LIBS)
+	$(EXPAND_CCC) $(CXXFLAGS) -o $@ $< $(WIN32_EXE_LDFLAGS) $(LDFLAGS) $(WRAP_LDFLAGS) $(STATIC_LIBS) $(MOZ_PROGRAM_LDFLAGS) $(SHARED_LIBS) $(EXTRA_LIBS) $(OS_LIBS) $(BIN_FLAGS) $(STLPORT_LIBS)
 	$(call CHECK_BINARY,$@)
 endif # WINNT && !GNU_CC