[binutils-gdb] MSP430: Fix alignment of __*_array_start symbols in default linker script
Jozef Lawrynowicz
jozefl@sourceware.org
Fri Aug 28 13:02:08 GMT 2020
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=64b63c2993db8606334f6f0852b4e7bb70b5682a
commit 64b63c2993db8606334f6f0852b4e7bb70b5682a
Author: Jozef Lawrynowicz <jozef.l@mittosystems.com>
Date: Fri Aug 28 13:56:53 2020 +0100
MSP430: Fix alignment of __*_array_start symbols in default linker script
__{preinit,init,fini}_array_start symbols must be word aligned in
linker scripts. If the section preceding the __*_array_start symbol
has an odd size, then a NULL byte will be present between the start
symbol and the .*_array section itself, when the section gets
automatically word-aligned.
This results in a branch to an invalid address when the CRT startup
code tries to run through the functions listed in the array sections.
Some MSP430 linker scripts do not align the __*_array start symbols, so
this added warning will catch that problem and help the user avoid
the potential incorrect execution of the program.
ld/ChangeLog:
* emultempl/msp430.em (input_section_exists): New.
(check_array_section_alignment): New.
(gld${EMULATION_NAME}_finish): New.
* scripttempl/elf32msp430.sc: Add ALIGN directives before the
definition of __*_array_start symbols.
* testsuite/ld-msp430-elf/finiarray-warn.ld: New test.
* testsuite/ld-msp430-elf/finiarray-warn.r: New test.
* testsuite/ld-msp430-elf/initarray-nowarn.ld: New test.
* testsuite/ld-msp430-elf/initarray-warn.ld: New test.
* testsuite/ld-msp430-elf/initarray-warn.r: New test.
* testsuite/ld-msp430-elf/initarray.s: New test.
* testsuite/ld-msp430-elf/msp430-elf.exp: Run new tests.
* testsuite/ld-msp430-elf/preinitarray-warn.ld: New test.
* testsuite/ld-msp430-elf/preinitarray-warn.r: New test.
Diff:
---
ld/ChangeLog | 17 ++++++
ld/emultempl/msp430.em | 81 ++++++++++++++++++++++++-
ld/scripttempl/elf32msp430.sc | 3 +
ld/testsuite/ld-msp430-elf/finiarray-warn.ld | 46 ++++++++++++++
ld/testsuite/ld-msp430-elf/finiarray-warn.r | 1 +
ld/testsuite/ld-msp430-elf/initarray-nowarn.ld | 45 ++++++++++++++
ld/testsuite/ld-msp430-elf/initarray-nowarn.r | 0
ld/testsuite/ld-msp430-elf/initarray-warn.ld | 46 ++++++++++++++
ld/testsuite/ld-msp430-elf/initarray-warn.r | 1 +
ld/testsuite/ld-msp430-elf/initarray.s | 21 +++++++
ld/testsuite/ld-msp430-elf/msp430-elf.exp | 13 ++++
ld/testsuite/ld-msp430-elf/preinitarray-warn.ld | 46 ++++++++++++++
ld/testsuite/ld-msp430-elf/preinitarray-warn.r | 1 +
13 files changed, 320 insertions(+), 1 deletion(-)
diff --git a/ld/ChangeLog b/ld/ChangeLog
index e2ca7f0df3d..77e39a56145 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,20 @@
+2020-08-28 Jozef Lawrynowicz <jozef.l@mittosystems.com>
+
+ * emultempl/msp430.em (input_section_exists): New.
+ (check_array_section_alignment): New.
+ (gld${EMULATION_NAME}_finish): New.
+ * scripttempl/elf32msp430.sc: Add ALIGN directives before the
+ definition of __*_array_start symbols.
+ * testsuite/ld-msp430-elf/finiarray-warn.ld: New test.
+ * testsuite/ld-msp430-elf/finiarray-warn.r: New test.
+ * testsuite/ld-msp430-elf/initarray-nowarn.ld: New test.
+ * testsuite/ld-msp430-elf/initarray-warn.ld: New test.
+ * testsuite/ld-msp430-elf/initarray-warn.r: New test.
+ * testsuite/ld-msp430-elf/initarray.s: New test.
+ * testsuite/ld-msp430-elf/msp430-elf.exp: Run new tests.
+ * testsuite/ld-msp430-elf/preinitarray-warn.ld: New test.
+ * testsuite/ld-msp430-elf/preinitarray-warn.r: New test.
+
2020-08-28 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* ldmisc.c (vfinfo): Support new "%pU" format specifier.
diff --git a/ld/emultempl/msp430.em b/ld/emultempl/msp430.em
index a47998a00a9..7b78a53d7e1 100644
--- a/ld/emultempl/msp430.em
+++ b/ld/emultempl/msp430.em
@@ -826,6 +826,85 @@ msp430_elf_after_allocation (void)
gld${EMULATION_NAME}_after_allocation ();
}
+/* Return TRUE if a non-debug input section in L has positive size and matches
+ the given name. */
+static int
+input_section_exists (lang_statement_union_type * l, const char * name)
+{
+ while (l != NULL)
+ {
+ switch (l->header.type)
+ {
+ case lang_input_section_enum:
+ if ((l->input_section.section->flags & SEC_ALLOC)
+ && l->input_section.section->size > 0
+ && !strcmp (l->input_section.section->name, name))
+ return TRUE;
+ break;
+
+ case lang_wild_statement_enum:
+ if (input_section_exists (l->wild_statement.children.head, name))
+ return TRUE;
+ break;
+
+ default:
+ break;
+ }
+ l = l->header.next;
+ }
+ return FALSE;
+}
+
+/* Some MSP430 linker scripts do not include ALIGN directives to ensure
+ __preinit_array_start, __init_array_start or __fini_array_start are word
+ aligned.
+ If __*_array_start symbols are not word aligned, the code in crt0 to run
+ through the array and call the functions will crash.
+ To avoid warning unnecessarily when the .*_array sections are not being
+ used for running constructors/destructors, only emit the warning if
+ the associated section exists and has size. */
+static void
+check_array_section_alignment (void)
+{
+ int i;
+ lang_output_section_statement_type * rodata_sec;
+ lang_output_section_statement_type * rodata2_sec;
+ const char * array_names[3][2] = { { ".init_array", "__init_array_start" },
+ { ".preinit_array", "__preinit_array_start" },
+ { ".fini_array", "__fini_array_start" } };
+
+ /* .{preinit,init,fini}_array could be in either .rodata or .rodata2. */
+ rodata_sec = lang_output_section_find (".rodata");
+ rodata2_sec = lang_output_section_find (".rodata2");
+ if (rodata_sec == NULL && rodata2_sec == NULL)
+ return;
+
+ /* There are 3 .*_array sections which must be checked for alignment. */
+ for (i = 0; i < 3; i++)
+ {
+ struct bfd_link_hash_entry * sym;
+ if (((rodata_sec && input_section_exists (rodata_sec->children.head,
+ array_names[i][0]))
+ || (rodata2_sec && input_section_exists (rodata2_sec->children.head,
+ array_names[i][0])))
+ && (sym = bfd_link_hash_lookup (link_info.hash, array_names[i][1],
+ FALSE, FALSE, TRUE))
+ && sym->type == bfd_link_hash_defined
+ && sym->u.def.value % 2)
+ {
+ einfo ("%P: warning: \"%s\" symbol (%pU) is not word aligned\n",
+ array_names[i][1], NULL);
+ }
+ }
+}
+
+static void
+gld${EMULATION_NAME}_finish (void)
+{
+ finish_default ();
+ check_array_section_alignment ();
+}
+
struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
{
${LDEMUL_BEFORE_PARSE-gld${EMULATION_NAME}_before_parse},
@@ -842,7 +921,7 @@ struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
${LDEMUL_GET_SCRIPT-gld${EMULATION_NAME}_get_script},
"${EMULATION_NAME}",
"${OUTPUT_FORMAT}",
- ${LDEMUL_FINISH-finish_default},
+ gld${EMULATION_NAME}_finish,
${LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS-NULL},
${LDEMUL_OPEN_DYNAMIC_ARCHIVE-NULL},
${LDEMUL_PLACE_ORPHAN-gld${EMULATION_NAME}_place_orphan},
diff --git a/ld/scripttempl/elf32msp430.sc b/ld/scripttempl/elf32msp430.sc
index f9ee9ff65be..4206d797b87 100644
--- a/ld/scripttempl/elf32msp430.sc
+++ b/ld/scripttempl/elf32msp430.sc
@@ -208,15 +208,18 @@ SECTIONS
KEEP (*(.gcc_except_table)) *(.gcc_except_table.*)
+ . = ALIGN(2);
PROVIDE (__preinit_array_start = .);
KEEP (*(.preinit_array))
PROVIDE (__preinit_array_end = .);
+ . = ALIGN(2);
PROVIDE (__init_array_start = .);
KEEP (*(SORT(.init_array.*)))
KEEP (*(.init_array))
PROVIDE (__init_array_end = .);
+ . = ALIGN(2);
PROVIDE (__fini_array_start = .);
KEEP (*(.fini_array))
KEEP (*(SORT(.fini_array.*)))
diff --git a/ld/testsuite/ld-msp430-elf/finiarray-warn.ld b/ld/testsuite/ld-msp430-elf/finiarray-warn.ld
new file mode 100644
index 00000000000..c9342934b45
--- /dev/null
+++ b/ld/testsuite/ld-msp430-elf/finiarray-warn.ld
@@ -0,0 +1,46 @@
+/* Script for ld testsuite */
+OUTPUT_ARCH(msp430)
+ENTRY(_start)
+
+SECTIONS
+{
+ .text :
+ {
+ PROVIDE (_start = .);
+ . = ALIGN(2);
+ *(.text .stub .text.* .gnu.linkonce.t.* .text:*)
+ }
+
+ .rodata :
+ {
+ *(.rodata.* .rodata)
+ . = ALIGN(2);
+ PROVIDE (__preinit_array_start = .);
+ KEEP (*(SORT(.preinit_array.*)))
+ KEEP (*(.preinit_array))
+ PROVIDE (__preinit_array_end = .);
+ . = ALIGN(2);
+ PROVIDE (__init_array_start = .);
+ KEEP (*(SORT(.init_array.*)))
+ KEEP (*(.init_array))
+ PROVIDE (__init_array_end = .);
+ . = ALIGN(2);
+ . += 1;
+ PROVIDE (__fini_array_start = .);
+ KEEP (*(SORT(.fini_array.*)))
+ KEEP (*(.fini_array))
+ PROVIDE (__fini_array_end = .);
+ }
+
+ .data :
+ {
+ . = ALIGN(2);
+ *(.data.* .data)
+ }
+
+ .bss :
+ {
+ . = ALIGN(2);
+ *(.bss.* .bss)
+ }
+}
diff --git a/ld/testsuite/ld-msp430-elf/finiarray-warn.r b/ld/testsuite/ld-msp430-elf/finiarray-warn.r
new file mode 100644
index 00000000000..ba3fa8348bd
--- /dev/null
+++ b/ld/testsuite/ld-msp430-elf/finiarray-warn.r
@@ -0,0 +1 @@
+.*warning: "__fini_array_start" symbol \(finiarray-warn.ld\) is not word aligned
diff --git a/ld/testsuite/ld-msp430-elf/initarray-nowarn.ld b/ld/testsuite/ld-msp430-elf/initarray-nowarn.ld
new file mode 100644
index 00000000000..866c3241380
--- /dev/null
+++ b/ld/testsuite/ld-msp430-elf/initarray-nowarn.ld
@@ -0,0 +1,45 @@
+/* Script for ld testsuite */
+OUTPUT_ARCH(msp430)
+ENTRY(_start)
+
+SECTIONS
+{
+ .text :
+ {
+ PROVIDE (_start = .);
+ . = ALIGN(2);
+ *(.text .stub .text.* .gnu.linkonce.t.* .text:*)
+ }
+
+ .rodata :
+ {
+ *(.rodata.* .rodata)
+ . = ALIGN(2);
+ PROVIDE (__preinit_array_start = .);
+ KEEP (*(SORT(.preinit_array.*)))
+ KEEP (*(.preinit_array))
+ PROVIDE (__preinit_array_end = .);
+ . = ALIGN(2);
+ PROVIDE (__init_array_start = .);
+ KEEP (*(SORT(.init_array.*)))
+ KEEP (*(.init_array))
+ PROVIDE (__init_array_end = .);
+ . = ALIGN(2);
+ PROVIDE (__fini_array_start = .);
+ KEEP (*(SORT(.fini_array.*)))
+ KEEP (*(.fini_array))
+ PROVIDE (__fini_array_end = .);
+ }
+
+ .data :
+ {
+ . = ALIGN(2);
+ *(.data.* .data)
+ }
+
+ .bss :
+ {
+ . = ALIGN(2);
+ *(.bss.* .bss)
+ }
+}
diff --git a/ld/testsuite/ld-msp430-elf/initarray-nowarn.r b/ld/testsuite/ld-msp430-elf/initarray-nowarn.r
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/ld/testsuite/ld-msp430-elf/initarray-warn.ld b/ld/testsuite/ld-msp430-elf/initarray-warn.ld
new file mode 100644
index 00000000000..fc00d9025e5
--- /dev/null
+++ b/ld/testsuite/ld-msp430-elf/initarray-warn.ld
@@ -0,0 +1,46 @@
+/* Script for ld testsuite */
+OUTPUT_ARCH(msp430)
+ENTRY(_start)
+
+SECTIONS
+{
+ .text :
+ {
+ PROVIDE (_start = .);
+ . = ALIGN(2);
+ *(.text .stub .text.* .gnu.linkonce.t.* .text:*)
+ }
+
+ .rodata :
+ {
+ *(.rodata.* .rodata)
+ . = ALIGN(2);
+ PROVIDE (__preinit_array_start = .);
+ KEEP (*(SORT(.preinit_array.*)))
+ KEEP (*(.preinit_array))
+ PROVIDE (__preinit_array_end = .);
+ . = ALIGN(2);
+ . += 1;
+ PROVIDE (__init_array_start = .);
+ KEEP (*(SORT(.init_array.*)))
+ KEEP (*(.init_array))
+ PROVIDE (__init_array_end = .);
+ . = ALIGN(2);
+ PROVIDE (__fini_array_start = .);
+ KEEP (*(SORT(.fini_array.*)))
+ KEEP (*(.fini_array))
+ PROVIDE (__fini_array_end = .);
+ }
+
+ .data :
+ {
+ . = ALIGN(2);
+ *(.data.* .data)
+ }
+
+ .bss :
+ {
+ . = ALIGN(2);
+ *(.bss.* .bss)
+ }
+}
diff --git a/ld/testsuite/ld-msp430-elf/initarray-warn.r b/ld/testsuite/ld-msp430-elf/initarray-warn.r
new file mode 100644
index 00000000000..35abd7bfe97
--- /dev/null
+++ b/ld/testsuite/ld-msp430-elf/initarray-warn.r
@@ -0,0 +1 @@
+.*warning: "__init_array_start" symbol \(initarray-warn.ld\) is not word aligned
diff --git a/ld/testsuite/ld-msp430-elf/initarray.s b/ld/testsuite/ld-msp430-elf/initarray.s
new file mode 100644
index 00000000000..abbf86e8838
--- /dev/null
+++ b/ld/testsuite/ld-msp430-elf/initarray.s
@@ -0,0 +1,21 @@
+.text
+ .section .preinit_array,"aw"
+ .short 42
+
+ .section .init_array,"aw"
+ .short 43
+
+ .section .fini_array,"aw"
+ .short 44
+
+.text
+ .global main
+ .type main, @function
+main:
+ MOV #__preinit_array_start, R8
+ MOV #__init_array_start, R9
+ MOV #__fini_array_start, R10
+ CALL @R8
+ CALL @R9
+ CALL @R10
+ RET
diff --git a/ld/testsuite/ld-msp430-elf/msp430-elf.exp b/ld/testsuite/ld-msp430-elf/msp430-elf.exp
index e9a0fdc6292..a2fa4db48d4 100644
--- a/ld/testsuite/ld-msp430-elf/msp430-elf.exp
+++ b/ld/testsuite/ld-msp430-elf/msp430-elf.exp
@@ -163,6 +163,19 @@ set msp430warntests {
{{ld warn-no-lower-data.r}} "warn-no-lower-data"}
}
+set msp430arraytests {
+ { "Warn when __preinit_array_start is not word aligned" "-T preinitarray-warn.ld" "" ""
+ {initarray.s} {{ld preinitarray-warn.r}} "preinitarray-warn"}
+ { "Warn when __init_array_start is not word aligned" "-T initarray-warn.ld" "" ""
+ {initarray.s} {{ld initarray-warn.r}} "initarray-warn"}
+ { "Warn when __fini_array_start is not word aligned" "-T finiarray-warn.ld" "" ""
+ {initarray.s} {{ld finiarray-warn.r}} "finiarray-warn"}
+ { "Don't warn when __{preinit,init,fini}_array_start are word aligned" "-T initarray-nowarn.ld" "" ""
+ {initarray.s} {{ld initarray-nowarn.r}} "initarray-nowarn"}
+}
+
+run_ld_link_tests $msp430arraytests
+
# Don't run further tests when msp430 ISA is selected
if {[string match "*-mcpu=msp430 *" [board_info [target_info name] multilib_flags]]
|| [string match "*-mcpu=msp430" [board_info [target_info name] multilib_flags]]} {
diff --git a/ld/testsuite/ld-msp430-elf/preinitarray-warn.ld b/ld/testsuite/ld-msp430-elf/preinitarray-warn.ld
new file mode 100644
index 00000000000..acbe7f5e65e
--- /dev/null
+++ b/ld/testsuite/ld-msp430-elf/preinitarray-warn.ld
@@ -0,0 +1,46 @@
+/* Script for ld testsuite */
+OUTPUT_ARCH(msp430)
+ENTRY(_start)
+
+SECTIONS
+{
+ .text :
+ {
+ PROVIDE (_start = .);
+ . = ALIGN(2);
+ *(.text .stub .text.* .gnu.linkonce.t.* .text:*)
+ }
+
+ .rodata :
+ {
+ *(.rodata.* .rodata)
+ . = ALIGN(2);
+ . += 1;
+ PROVIDE (__preinit_array_start = .);
+ KEEP (*(SORT(.preinit_array.*)))
+ KEEP (*(.preinit_array))
+ PROVIDE (__preinit_array_end = .);
+ . = ALIGN(2);
+ PROVIDE (__init_array_start = .);
+ KEEP (*(SORT(.init_array.*)))
+ KEEP (*(.init_array))
+ PROVIDE (__init_array_end = .);
+ . = ALIGN(2);
+ PROVIDE (__fini_array_start = .);
+ KEEP (*(SORT(.fini_array.*)))
+ KEEP (*(.fini_array))
+ PROVIDE (__fini_array_end = .);
+ }
+
+ .data :
+ {
+ . = ALIGN(2);
+ *(.data.* .data)
+ }
+
+ .bss :
+ {
+ . = ALIGN(2);
+ *(.bss.* .bss)
+ }
+}
diff --git a/ld/testsuite/ld-msp430-elf/preinitarray-warn.r b/ld/testsuite/ld-msp430-elf/preinitarray-warn.r
new file mode 100644
index 00000000000..ab12e42d46e
--- /dev/null
+++ b/ld/testsuite/ld-msp430-elf/preinitarray-warn.r
@@ -0,0 +1 @@
+.*warning: "__preinit_array_start" symbol \(preinitarray-warn.ld\) is not word aligned
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