From: H.J. Lu <hjl.tools@gmail.com>
Date: Fri, 7 Feb 2020 03:37:54 +0000 (-0800)
Subject: ld: Issue an error for GC on __patchable_function_entries section
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5242a0a000ad7d3f2fa1cd0023f692d53261b302;p=binutils-gdb.git

ld: Issue an error for GC on __patchable_function_entries section

__patchable_function_entries section is generated by a compiler with
-fpatchable-function-entry=XX.  The assembly code looks like this:

---
	.text
	.globl	_start
	.type	_start, %function
_start:
	.section __patchable_function_entries,"aw",%progbits
	.dc.a	.LPFE1
	.text
.LPFE1:
	.byte 0
---

But --gc-sections will silently remove __patchable_function_entries
section and generate corrupt result.  This patch disallows garbage
collection on __patchable_function_entries section without linked-to
section.

bfd/

	PR ld/25490
	* elflink.c (_bfd_elf_gc_mark_extra_sections): Issue an error
	for garbage collection on __patchable_function_entries section
	without linked-to section.

ld/

	PR ld/25490
	* testsuite/ld-elf/pr25490-1.d: New file.
	* testsuite/ld-elf/pr25490-1.s: Likewise.
---

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 99718857071..e1a84123254 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2020-02-06  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/25490
+	* elflink.c (_bfd_elf_gc_mark_extra_sections): Issue an error
+	for garbage collection on __patchable_function_entries section
+	without linked-to section.
+
 2020-02-06  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR gas/25381
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 30a572d32de..3add9f18bd7 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -13365,6 +13365,13 @@ _bfd_elf_gc_mark_extra_sections (struct bfd_link_info *info,
 	      && (isec->flags & SEC_DEBUGGING)
 	      && CONST_STRNEQ (isec->name, ".debug_line."))
 	    debug_frag_seen = TRUE;
+	  else if (strcmp (bfd_section_name (isec),
+			   "__patchable_function_entries") == 0
+		   && elf_linked_to_section (isec) == NULL)
+	      info->callbacks->einfo (_("%F%P: %pB(%pA): error: "
+					"need linked-to section "
+					"for --gc-sections\n"),
+				      isec->owner, isec);
 	}
 
       /* If no non-note alloc section in this file will be kept, then
diff --git a/ld/ChangeLog b/ld/ChangeLog
index b5c8326efb6..3ad571f1691 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,9 @@
+2020-02-06  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/25490
+	* testsuite/ld-elf/pr25490-1.d: New file.
+	* testsuite/ld-elf/pr25490-1.s: Likewise.
+
 2020-02-06  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR ld/24526
diff --git a/ld/testsuite/ld-elf/pr25490-1.d b/ld/testsuite/ld-elf/pr25490-1.d
new file mode 100644
index 00000000000..3f582645899
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr25490-1.d
@@ -0,0 +1,3 @@
+#ld: --gc-sections -e _start
+#target: [check_gc_sections_available]
+#error: .*\(__patchable_function_entries\): error: need linked-to section for --gc-sections
diff --git a/ld/testsuite/ld-elf/pr25490-1.s b/ld/testsuite/ld-elf/pr25490-1.s
new file mode 100644
index 00000000000..51ba1ea8014
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr25490-1.s
@@ -0,0 +1,9 @@
+	.text
+	.globl	_start
+	.type	_start, %function
+_start:
+	.section	__patchable_function_entries,"aw",%progbits
+	.dc.a	.LPFE1
+	.text
+.LPFE1:
+	.byte 0