Add experimental support for --gc-sections with COFF and PE based targets.

	PR ld/11539
bfd	* coffcode.h (coff_bfd_gc_sections): Define default
	to bfd_coff_gc_sections function.
	* cofflink.c (init_reloc_cookie): Copy and adjust coff
	related code about gc-sections from elflink.c to here.
	(fini_reloc_cookie): Likewise.
	(init_reloc_cookie_rels): Likewise.
	(fini_reloc_cookie_rels): Likewise.
	(init_reloc_cookie_for_section): Likewise.
	(fini_reloc_cookie_for_section): Likewise.
	(_bfd_coff_gc_mark_hook): Likewise.
	(_bfd_coff_gc_mark_rsec): Likewise.
	(_bfd_coff_gc_mark_reloc): Likewise.
	(_bfd_coff_gc_mark): Likewise.
	(_bfd_coff_gc_mark_extra_sections): Likewise.
	(coff_gc_sweep_symbol_info): Likewise.
	(coff_gc_sweep_symbol): Likewise.
	(gc_sweep_hook_fn): Likewise.
	(coff_gc_sweep): Likewise.
	(bfd_coff_gc_sections): Likewise.
	(_bfd_coff_gc_keep): Likewise.
	* libcoff.h (coff_reloc_cookie): New struct.
	(bfd_coff_gc_sections): New prototype.
	(coff_gc_mark_hook_fn): New type.

ld	* scripttempl/pep.sc: Mark .idata*, .CRT*, .tls*,
	.rsrc*, .init, .ctor*, .dtor*, .fini, .jcr,
	.eh_frame, .pdata. .xdata, and .gcc_except_table sections
	as KEEP.
	* scripttempl/pe.sc: Likewise.

1 files changed, 34 insertions, 26 deletions

diff --git a/ld/scripttempl/pep.sc b/ld/scripttempl/pep.sc
index 50b4104..6e78b21 100644
--- a/ld/scripttempl/pep.sc
+++ b/ld/scripttempl/pep.sc
@@ -30,29 +30,29 @@ if test "${RELOCATING}"; then
              *(SORT(.rdata$*))'
   fi
   R_IDATA234='
-    SORT(*)(.idata$2)
-    SORT(*)(.idata$3)
+    KEEP (SORT(*)(.idata$2))
+    KEEP (SORT(*)(.idata$3))
     /* These zeroes mark the end of the import list.  */
     LONG (0); LONG (0); LONG (0); LONG (0); LONG (0);
-    SORT(*)(.idata$4)'
+    KEEP (SORT(*)(.idata$4))'
   R_IDATA5='SORT(*)(.idata$5)'
   R_IDATA67='
-    SORT(*)(.idata$6)
-    SORT(*)(.idata$7)'
-  R_CRT_XC='*(SORT(.CRT$XC*))  /* C initialization */'
-  R_CRT_XI='*(SORT(.CRT$XI*))  /* C++ initialization */'
-  R_CRT_XL='*(SORT(.CRT$XL*))  /* TLS callbacks */'
-  R_CRT_XP='*(SORT(.CRT$XP*))  /* Pre-termination */'
-  R_CRT_XT='*(SORT(.CRT$XT*))  /* Termination */'
+    KEEP (SORT(*)(.idata$6))
+    KEEP (SORT(*)(.idata$7))'
+  R_CRT_XC='KEEP (*(SORT(.CRT$XC*)))  /* C initialization */'
+  R_CRT_XI='KEEP (*(SORT(.CRT$XI*)))  /* C++ initialization */'
+  R_CRT_XL='KEEP (*(SORT(.CRT$XL*)))  /* TLS callbacks */'
+  R_CRT_XP='KEEP (*(SORT(.CRT$XP*)))  /* Pre-termination */'
+  R_CRT_XT='KEEP (*(SORT(.CRT$XT*)))  /* Termination */'
   R_TLS='
-    *(.tls$AAA)
-    *(.tls)
-    *(.tls$)
-    *(SORT(.tls$*))
-    *(.tls$ZZZ)'
+    KEEP (*(.tls$AAA))
+    KEEP (*(.tls))
+    KEEP (*(.tls$))
+    KEEP (*(SORT(.tls$*)))
+    KEEP (*(.tls$ZZZ))'
   R_RSRC='
-    *(.rsrc)
-    *(.rsrc$*)'
+    KEEP (*(.rsrc))
+    KEEP (*(.rsrc$*))'
 else
   R_TEXT=
   R_DATA=
@@ -85,7 +85,7 @@ SECTIONS
   ${RELOCATING+. = ALIGN(__section_alignment__);}
   .text ${RELOCATING+ __image_base__ + ( __section_alignment__ < ${TARGET_PAGE_SIZE} ? . : __section_alignment__ )} :
   {
-    ${RELOCATING+ *(.init)}
+    ${RELOCATING+ KEEP(*(.init))}
     *(.text)
     ${R_TEXT}
     ${RELOCATING+ *(.text.*)}
@@ -94,14 +94,22 @@ SECTIONS
     *(.glue_7)
     ${CONSTRUCTING+. = ALIGN(8);}
     ${CONSTRUCTING+ ___CTOR_LIST__ = .; __CTOR_LIST__ = . ;
-			LONG (-1); LONG (-1);*(.ctors); *(.ctor); *(SORT(.ctors.*));  LONG (0); LONG (0); }
+			LONG (-1); LONG (-1);
+			KEEP (*(.ctors));
+			KEEP (*(.ctor));
+			KEEP (*(SORT(.ctors.*)));
+			LONG (0); LONG (0); }
     ${CONSTRUCTING+ ___DTOR_LIST__ = .; __DTOR_LIST__ = . ;
-			LONG (-1); LONG (-1); *(.dtors); *(.dtor); *(SORT(.dtors.*));  LONG (0); LONG (0); }
-    ${RELOCATING+ *(.fini)}
+			LONG (-1); LONG (-1);
+			KEEP (*(.dtors));
+			KEEP (*(.dtor));
+			KEEP (*(SORT(.dtors.*)));
+			LONG (0); LONG (0); }
+    ${RELOCATING+ KEEP (*(.fini))}
     /* ??? Why is .gcc_exc here?  */
     ${RELOCATING+ *(.gcc_exc)}
     ${RELOCATING+PROVIDE (etext = .);}
-    ${RELOCATING+ *(.gcc_except_table)}
+    ${RELOCATING+ KEEP (*(.gcc_except_table))}
   }
 
   /* The Cygwin32 library uses a section to avoid copying certain data
@@ -116,7 +124,7 @@ SECTIONS
     *(.data)
     *(.data2)
     ${R_DATA}
-    *(.jcr)
+    KEEP(*(.jcr))
     ${RELOCATING+__data_end__ = . ;}
     ${RELOCATING+*(.data_cygwin_nocopy)}
   }
@@ -136,17 +144,17 @@ SECTIONS
 
   .eh_frame ${RELOCATING+BLOCK(__section_alignment__)} :
   {
-    *(.eh_frame*)
+    KEEP (*(.eh_frame*))
   }
 
   .pdata ${RELOCATING+BLOCK(__section_alignment__)} :
   {
-    *(.pdata*)
+    KEEP(*(.pdata*))
   }
 
   .xdata ${RELOCATING+BLOCK(__section_alignment__)} :
   {
-    *(.xdata*)
+    KEEP(*(.xdata*))
   }
 
   .bss ${RELOCATING+BLOCK(__section_alignment__)} :