LoongArch: Fix R_LARCH_IRELATIVE insertion after elf_link_sort_relocs

loongarch_elf_finish_dynamic_symbol is called after elf_link_sort_relocs
if -z combreloc.  elf_link_sort_relocs redistributes the contents of
.rela.* sections those would be merged into .rela.dyn, so the slot for
R_LARCH_IRELATIVE may be out of relplt->contents now.

To make things worse, the boundary check

    dyn < dyn + relplt->size / sizeof (*dyn)

is obviously wrong ("x + 10 < x"? :), causing the issue undetected
during the linking process and the resulted executable suddenly crashes
at runtime.

The issue was found during an attempt to add static-pie support to the
toolchain.

Fix it by iterating through the inputs of .rela.dyn to find the slot.

3 files changed, 39 insertions, 0 deletions

diff --git a/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp b/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
index dfa8ee1..726ee82 100644
--- a/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
+++ b/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
@@ -31,6 +31,7 @@ if [istarget "loongarch64-*-*"] {
     run_dump_test "macro_op"
     run_dump_test "syscall"
     run_dump_test "disas-jirl"
+    run_dump_test "local-ifunc-reloc"
 }
 
 if [istarget "loongarch32-*-*"] {
diff --git a/ld/testsuite/ld-loongarch-elf/local-ifunc-reloc.d b/ld/testsuite/ld-loongarch-elf/local-ifunc-reloc.d
new file mode 100644
index 0000000..29f2d3f
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/local-ifunc-reloc.d
@@ -0,0 +1,10 @@
+#as:
+#ld: -shared -z combreloc
+#objdump: -R
+
+.*: +file format .*
+
+DYNAMIC RELOCATION RECORDS
+OFFSET +TYPE +VALUE
+[[:xdigit:]]+ R_LARCH_IRELATIVE +\*ABS\*\+0x[[:xdigit:]]+
+[[:xdigit:]]+ R_LARCH_64 +test
diff --git a/ld/testsuite/ld-loongarch-elf/local-ifunc-reloc.s b/ld/testsuite/ld-loongarch-elf/local-ifunc-reloc.s
new file mode 100644
index 0000000..77c4874
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/local-ifunc-reloc.s
@@ -0,0 +1,28 @@
+.text
+.align 2
+
+.local ifunc
+.type ifunc, @gnu_indirect_function
+.set ifunc, resolver
+
+resolver:
+  la.local $a0, impl
+  jr $ra
+
+impl:
+  li.w $a0, 42
+  jr $ra
+
+.global test
+.type test, @function
+test:
+  move $s0, $ra
+  bl ifunc
+  xori $a0, $a0, 42
+  jr $s0
+
+.data
+.global ptr
+.type ptr, @object
+ptr:
+  .dword test