[PATCH] ARM: Resolve thumb_bl fixup in same MCFragment.

[Logan Chien]

  Use the .space directive to pad the instructions.

Hi rengolin,

http://llvm-reviews.chandlerc.com/D2675

CHANGE SINCE LAST DIFF
  http://llvm-reviews.chandlerc.com/D2675?vs=6826&id=6853#toc

Files:
  lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
  test/MC/ARM/thumb-far-jump.s

Index: lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
===================================================================
--- lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
+++ lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
@@ -565,11 +565,18 @@
         Value |= 1;
     }
   }
+  // For Thumb1 BL instruction, it is possible to be a long jump between
+  // the basic blocks of the same function.  Thus, we would like to resolve
+  // the offset when the destination has the same MCFragment.
+  if (A && (unsigned)Fixup.getKind() == ARM::fixup_arm_thumb_bl) {
+    const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
+    MCSymbolData &SymData = Asm.getSymbolData(Sym);
+    IsResolved = (SymData.getFragment() == DF);
+  }
   // We must always generate a relocation for BL/BLX instructions if we have
   // a symbol to reference, as the linker relies on knowing the destination
   // symbol's thumb-ness to get interworking right.
   if (A && ((unsigned)Fixup.getKind() == ARM::fixup_arm_thumb_blx ||
-            (unsigned)Fixup.getKind() == ARM::fixup_arm_thumb_bl ||
             (unsigned)Fixup.getKind() == ARM::fixup_arm_blx ||
             (unsigned)Fixup.getKind() == ARM::fixup_arm_uncondbl ||
             (unsigned)Fixup.getKind() == ARM::fixup_arm_condbl))
Index: test/MC/ARM/thumb-far-jump.s
===================================================================
--- /dev/null
+++ test/MC/ARM/thumb-far-jump.s
@@ -0,0 +1,26 @@
+@ RUN: llvm-mc < %s -triple thumbv5-linux-gnueabi -filetype=obj -o - \
+@ RUN:   | llvm-readobj -r | FileCheck %s
+	.syntax	unified
+
+	.text
+	.align	2
+	.globl	main
+	.type	main,%function
+	.thumb_func
+main:
+	bl	end
+	.space 8192
+end:
+	bl	main2
+	bx	lr
+
+	.text
+	.align	2
+	.globl	main2
+	.type	main2,%function
+	.thumb_func
+main2:
+	bx	lr
+
+@ CHECK-NOT: 0x0 R_ARM_THM_CALL end 0x0
+@ CHECK: 0x2004 R_ARM_THM_CALL main2 0x0
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D2675.2.patch
Type: text/x-patch
Size: 1873 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20140204/d862f739/attachment.bin>