[binutils-gdb] Add testcase ld-elf/merge4

[binutils-gdb] Add testcase ld-elf/merge4

[Michael Matz]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=ec15b12d0684b41f67b56623f6e9b5024bf08905

commit ec15b12d0684b41f67b56623f6e9b5024bf08905
Author: Michael Matz <matz@suse.de>
Date:   Wed Oct 12 17:29:43 2022 +0200

    Add testcase ld-elf/merge4
    
    to check a situation that once failed with the new section merging
    when it mishandled offsets pointing into alignment padding in mergable
    string sections (i.e. pointing to zeros).  It made bootstrap.exp fail
    but that depends on many factors to actually go wrong so this is a more
    explicit variant of it.

Diff:
---
 ld/testsuite/ld-elf/elf.exp    |  6 ++++++
 ld/testsuite/ld-elf/merge4.out |  3 +++
 ld/testsuite/ld-elf/merge4a.c  | 23 +++++++++++++++++++++++
 ld/testsuite/ld-elf/merge4b.s  | 23 +++++++++++++++++++++++
 4 files changed, 55 insertions(+)

diff --git a/ld/testsuite/ld-elf/elf.exp b/ld/testsuite/ld-elf/elf.exp
index a3a8994749d..1a160d084e0 100644
--- a/ld/testsuite/ld-elf/elf.exp
+++ b/ld/testsuite/ld-elf/elf.exp
@@ -607,4 +607,10 @@ run_ld_link_exec_tests [list \
     ] \
 ]
 
+set merge_exec_tests {
+    {"merge4" "" ""
+	{merge4a.c merge4b.s} "merge4" "merge4.out"}
+}
+run_ld_link_exec_tests $merge_exec_tests
+
 catch "exec rm -f tmpdir/preinit tmpdir/init tmpdir/fini tmpdir/init-mixed" status
diff --git a/ld/testsuite/ld-elf/merge4.out b/ld/testsuite/ld-elf/merge4.out
new file mode 100644
index 00000000000..92c1b71f712
--- /dev/null
+++ b/ld/testsuite/ld-elf/merge4.out
@@ -0,0 +1,3 @@
+1: foobar
+2: 
+3: blabla
diff --git a/ld/testsuite/ld-elf/merge4a.c b/ld/testsuite/ld-elf/merge4a.c
new file mode 100644
index 00000000000..133303e11ac
--- /dev/null
+++ b/ld/testsuite/ld-elf/merge4a.c
@@ -0,0 +1,23 @@
+extern const char * getstr3(int);
+extern int printf (const char *, ...);
+
+extern const char *addr_of_str;
+extern const char *addr_of_str2;
+
+/* "foobar" needs to be a string literal, so that it's put into
+   a mergable string section, then merged with the "foobar" from merge4b.s
+   and then (when the linker is buggy) doesn't cover the additional
+   nul byte after "foobar" in the asm source (which addr_of_str2 is supposed
+   to point into.  */
+const char * getstr3(int i)
+{
+  return i ? "blabla" : "foobar";
+}
+
+int main(void)
+{
+  printf ("1: %s\n", addr_of_str);
+  printf ("2: %s\n", addr_of_str2);
+  printf ("3: %s\n", getstr3(1));
+  return 0;
+}
diff --git a/ld/testsuite/ld-elf/merge4b.s b/ld/testsuite/ld-elf/merge4b.s
new file mode 100644
index 00000000000..d4b66aab5e6
--- /dev/null
+++ b/ld/testsuite/ld-elf/merge4b.s
@@ -0,0 +1,23 @@
+/* Check that pointing into padding zeros of string sections works. */
+	.section	.rodata.str1.1,"aMS",@progbits,1
+	.string ""
+.LC0:
+	.string	"foobar"
+1:
+	.string ""
+	.string "whatever"
+	.section .data
+	.globl addr_of_str
+	.type addr_of_str, @object
+addr_of_str:
+	.dc.a str
+	.globl addr_of_str2
+	.type addr_of_str2, @object
+addr_of_str2:
+	.dc.a 1b
+	.section	.rodata
+	.type	str, @object
+	.size	str, 7
+str:
+	.string	"foobar"
+	.section	.note.GNU-stack,"",@progbits