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-rw-r--r--bfd/elf32-arm.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 616efe6..5b8f5e5 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -2536,11 +2536,23 @@ static const bfd_vma elf32_arm_nacl_plt_entry [] =
0xea000000, /* b .Lplt_tail */
};
+/* PR 28924:
+ There was a bug due to too high values of THM_MAX_FWD_BRANCH_OFFSET and
+ THM2_MAX_FWD_BRANCH_OFFSET. The first macro concerns the case when Thumb-2
+ is not available, and second macro when Thumb-2 is available. Among other
+ things, they affect the range of branches represented as BLX instructions
+ in Encoding T2 defined in Section A8.8.25 of the ARM Architecture
+ Reference Manual ARMv7-A and ARMv7-R edition issue C.d. Such branches are
+ specified there to have a maximum forward offset that is a multiple of 4.
+ Previously, the respective values defined here were multiples of 2 but not
+ 4 and they are included in comments for reference. */
#define ARM_MAX_FWD_BRANCH_OFFSET ((((1 << 23) - 1) << 2) + 8)
-#define ARM_MAX_BWD_BRANCH_OFFSET ((-((1 << 23) << 2)) + 8)
-#define THM_MAX_FWD_BRANCH_OFFSET ((1 << 22) -2 + 4)
+#define ARM_MAX_BWD_BRANCH_OFFSET ((-((1 << 23) << 2)) + 8)
+#define THM_MAX_FWD_BRANCH_OFFSET ((1 << 22) - 4 + 4)
+/* #def THM_MAX_FWD_BRANCH_OFFSET ((1 << 22) - 2 + 4) */
#define THM_MAX_BWD_BRANCH_OFFSET (-(1 << 22) + 4)
-#define THM2_MAX_FWD_BRANCH_OFFSET (((1 << 24) - 2) + 4)
+#define THM2_MAX_FWD_BRANCH_OFFSET (((1 << 24) - 4) + 4)
+/* #def THM2_MAX_FWD_BRANCH_OFFSET (((1 << 24) - 2) + 4) */
#define THM2_MAX_BWD_BRANCH_OFFSET (-(1 << 24) + 4)
#define THM2_MAX_FWD_COND_BRANCH_OFFSET (((1 << 20) -2) + 4)
#define THM2_MAX_BWD_COND_BRANCH_OFFSET (-(1 << 20) + 4)