[PATCH] D34447: [ARM] Create relocations for beq.w branches to ARM function syms.

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
Herald added subscribers: kristof.beyls, javed.absar, aemerson.

The ARM ELF ABI requires the linker to do interworking for wide
conditional branches from Thumb code to ARM code.

That was pointed out by @peter.smith in the comments for https://reviews.llvm.org/D33436.


https://reviews.llvm.org/D34447

Files:
  lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
  test/MC/ARM/thumb2-beq-fixup.s


Index: test/MC/ARM/thumb2-beq-fixup.s
===================================================================
--- /dev/null
+++ test/MC/ARM/thumb2-beq-fixup.s
@@ -0,0 +1,39 @@
+@ RUN: llvm-mc < %s -triple armv7-linux-gnueabi -filetype=obj -o - \
+@ RUN:   | llvm-readobj -r | FileCheck %s
+
+  .code  16
+  .thumb_func
+thumb_caller:
+  beq.w internal_arm_fn
+  beq.w global_arm_fn
+  beq.w global_thumb_fn
+  beq.w internal_thumb_fn
+
+  .type  internal_arm_fn,%function
+  .code  32
+internal_arm_fn:
+  bx  lr
+
+  .globl  global_arm_fn
+  .type  global_arm_fn,%function
+  .code  32
+global_arm_fn:
+  bx  lr
+
+  .type  internal_thumb_fn,%function
+  .code  16
+  .thumb_func
+internal_thumb_fn:
+  bx  lr
+
+  .globl  global_thumb_fn
+  .type  global_thumb_fn,%function
+  .code  16
+  .thumb_func
+global_thumb_fn:
+  bx  lr
+
+@ CHECK: Section (3) .rel.text
+@ CHECK-NEXT: 0x0 R_ARM_THM_JUMP19 internal_arm_fn 0x0
+@ CHECK-NEXT: 0x4 R_ARM_THM_JUMP19 global_arm_fn 0x0
+@ CHECK-NEXT: }
Index: lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
===================================================================
--- lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
+++ lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
@@ -759,6 +759,7 @@
         IsResolved = false;
       if (!Asm.isThumbFunc(Sym) && (FixupKind == ARM::fixup_arm_thumb_br ||
                                     FixupKind == ARM::fixup_arm_thumb_bl ||
+                                    FixupKind == ARM::fixup_t2_condbranch ||
                                     FixupKind == ARM::fixup_t2_uncondbranch))
         IsResolved = false;
     }


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