[PATCH] ld: revert default dll characteristics for Cygwin.

[Jeremy Drake]

Mail thread from
https://cygwin.com/pipermail/cygwin/2021-February/247922.html suggests
these flags will NOT work for Cygwin, which relies on stable address
layouts for their fork() emulation.

In the process, renamed move_default_addr_high shell variable to
cygwin_beahior, as the old name wasn't quite accurate anymore and I
wanted to use it choose which dll characteristics flags to use by
default.

Also copied that switch to pe.em, as it was only in pep.em before but
32-bit also needed to switch defaults for Cygwin.
---
 ld/emultempl/pe.em  | 13 ++++++++++++-
 ld/emultempl/pep.em | 40 +++++++++++++++++++++-------------------
 2 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/ld/emultempl/pe.em b/ld/emultempl/pe.em
index 748a6b49412..9f757cc31dc 100644
--- a/ld/emultempl/pe.em
+++ b/ld/emultempl/pe.em
@@ -5,6 +5,16 @@ if [ -z "$MACHINE" ]; then
 else
   OUTPUT_ARCH=${ARCH}:${MACHINE}
 fi
+
+case ${target} in
+  *-*-cygwin*)
+    cygwin_behavior=1
+    ;;
+  *)
+    cygwin_behavior=0;
+    ;;
+esac
+
 rm -f e${EMULATION_NAME}.c
 (echo;echo;echo;echo;echo)>e${EMULATION_NAME}.c # there, now line numbers match ;-)
 fragment <<EOF
@@ -104,7 +114,8 @@ fragment <<EOF
 #define DEFAULT_PSEUDO_RELOC_VERSION 1
 #endif

-#define DEFAULT_DLL_CHARACTERISTICS	(IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE \
+#define DEFAULT_DLL_CHARACTERISTICS	(${cygwin_behavior} ? 0 : \
+					   IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE \
 					 | IMAGE_DLL_CHARACTERISTICS_NX_COMPAT)

 #if defined(TARGET_IS_i386pe) || ! defined(DLL_SUPPORT)
diff --git a/ld/emultempl/pep.em b/ld/emultempl/pep.em
index ff49c15c002..69f5bd04655 100644
--- a/ld/emultempl/pep.em
+++ b/ld/emultempl/pep.em
@@ -8,10 +8,10 @@ fi

 case ${target} in
   *-*-cygwin*)
-    move_default_addr_high=1
+    cygwin_behavior=1
     ;;
   *)
-    move_default_addr_high=0;
+    cygwin_behavior=0;
     ;;
 esac

@@ -99,45 +99,47 @@ fragment <<EOF
 #define DLL_SUPPORT
 #endif

-#define DEFAULT_DLL_CHARACTERISTICS	(IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE \
+#define DEFAULT_DLL_CHARACTERISTICS	(${cygwin_behavior} ? 0 : \
+					   IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE \
 					 | IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA \
 					 | IMAGE_DLL_CHARACTERISTICS_NX_COMPAT)

+
 #if defined(TARGET_IS_i386pep) || ! defined(DLL_SUPPORT)
 #define	PE_DEF_SUBSYSTEM		3
 #undef NT_EXE_IMAGE_BASE
 #define NT_EXE_IMAGE_BASE \
-  ((bfd_vma) (${move_default_addr_high} ? 0x100400000LL \
-					: 0x140000000LL))
+  ((bfd_vma) (${cygwin_behavior} ? 0x100400000LL \
+				 : 0x140000000LL))
 #undef NT_DLL_IMAGE_BASE
 #define NT_DLL_IMAGE_BASE \
-  ((bfd_vma) (${move_default_addr_high} ? 0x400000000LL \
-					: 0x180000000LL))
+  ((bfd_vma) (${cygwin_behavior} ? 0x400000000LL \
+				 : 0x180000000LL))
 #undef NT_DLL_AUTO_IMAGE_BASE
 #define NT_DLL_AUTO_IMAGE_BASE \
-  ((bfd_vma) (${move_default_addr_high} ? 0x400000000LL \
-					: 0x1C0000000LL))
+  ((bfd_vma) (${cygwin_behavior} ? 0x400000000LL \
+				 : 0x1C0000000LL))
 #undef NT_DLL_AUTO_IMAGE_MASK
 #define NT_DLL_AUTO_IMAGE_MASK \
-  ((bfd_vma) (${move_default_addr_high} ? 0x1ffff0000LL \
-					: 0x1ffff0000LL))
+  ((bfd_vma) (${cygwin_behavior} ? 0x1ffff0000LL \
+				 : 0x1ffff0000LL))
 #else
 #undef  NT_EXE_IMAGE_BASE
 #define NT_EXE_IMAGE_BASE \
-  ((bfd_vma) (${move_default_addr_high} ? 0x100010000LL \
-					: 0x10000LL))
+  ((bfd_vma) (${cygwin_behavior} ? 0x100010000LL \
+				 : 0x10000LL))
 #undef NT_DLL_IMAGE_BASE
 #define NT_DLL_IMAGE_BASE \
-  ((bfd_vma) (${move_default_addr_high} ? 0x110000000LL \
-					: 0x10000000LL))
+  ((bfd_vma) (${cygwin_behavior} ? 0x110000000LL \
+				 : 0x10000000LL))
 #undef NT_DLL_AUTO_IMAGE_BASE
 #define NT_DLL_AUTO_IMAGE_BASE \
-  ((bfd_vma) (${move_default_addr_high} ? 0x120000000LL \
-					: 0x61300000LL))
+  ((bfd_vma) (${cygwin_behavior} ? 0x120000000LL \
+				 : 0x61300000LL))
 #undef NT_DLL_AUTO_IMAGE_MASK
 #define NT_DLL_AUTO_IMAGE_MASK \
-  ((bfd_vma) (${move_default_addr_high} ? 0x0ffff0000LL \
-					: 0x0ffc0000LL))
+  ((bfd_vma) (${cygwin_behavior} ? 0x0ffff0000LL \
+				 : 0x0ffc0000LL))
 #undef  PE_DEF_SECTION_ALIGNMENT
 #define	PE_DEF_SUBSYSTEM		2
 #undef  PE_DEF_FILE_ALIGNMENT
-- 
2.30.1.windows.1