fixes target address tBL and tBLX and sets relocation type

of tBL/tBLX to R_ARM_THM_CALL (ARM ELF 4.7.1.6)

Patch by koan-sin tan.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131748 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 50 insertions, 2 deletions

diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index f2a3af6..6b81fc9 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -1441,6 +1441,17 @@ unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
     case ARM::fixup_t2_movw_lo16_pcrel:
       Type = ELF::R_ARM_THM_MOVW_PREL_NC;
       break;
+    case ARM::fixup_arm_thumb_bl:
+    case ARM::fixup_arm_thumb_blx:
+      switch (Modifier) {
+      case MCSymbolRefExpr::VK_ARM_PLT:
+        Type = ELF::R_ARM_THM_CALL;
+        break;
+      default:
+        Type = ELF::R_ARM_NONE;
+        break;
+      }
+      break;
     }
   } else {
     switch ((unsigned)Fixup.getKind()) {
diff --git a/lib/Target/ARM/ARMAsmBackend.cpp b/lib/Target/ARM/ARMAsmBackend.cpp
index 2cfd703..6923edb 100644
--- a/lib/Target/ARM/ARMAsmBackend.cpp
+++ b/lib/Target/ARM/ARMAsmBackend.cpp
@@ -308,7 +308,7 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
     //
     // Note that the halfwords are stored high first, low second; so we need
     // to transpose the fixup value here to map properly.
-    unsigned isNeg = (int64_t(Value) < 0) ? 1 : 0;
+    unsigned isNeg = (int64_t(Value - 4) < 0) ? 1 : 0;
     uint32_t Binary = 0;
     Value = 0x3fffff & ((Value - 4) >> 1);
     Binary  = (Value & 0x7ff) << 16;    // Low imm11 value.
@@ -326,7 +326,7 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
     //
     // Note that the halfwords are stored high first, low second; so we need
     // to transpose the fixup value here to map properly.
-    unsigned isNeg = (int64_t(Value) < 0) ? 1 : 0;
+    unsigned isNeg = (int64_t(Value-4) < 0) ? 1 : 0;
     uint32_t Binary = 0;
     Value = 0xfffff & ((Value - 2) >> 2);
     Binary  = (Value & 0x3ff) << 17;    // Low imm10L value.
diff --git a/test/MC/ARM/elf-thumbfunc-reloc.ll b/test/MC/ARM/elf-thumbfunc-reloc.ll
new file mode 100644
index 0000000..6fce403
--- /dev/null
+++ b/test/MC/ARM/elf-thumbfunc-reloc.ll
@@ -0,0 +1,37 @@
+; RUN: llc %s -mtriple=thumbv7-linux-gnueabi -relocation-model=pic \
+; RUN: -filetype=obj -o - | elf-dump --dump-section-data | \
+; RUN: FileCheck %s
+
+; FIXME: This file needs to be in .s form!
+; We wanna test relocatable thumb function call,
+; but ARMAsmParser cannot handle "bl foo(PLT)" yet
+
+target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:64:128-a0:0:32-n32"
+target triple = "thumbv7-none--gnueabi"
+
+define void @foo() nounwind {
+entry:
+  ret void
+}
+
+define void @bar() nounwind {
+entry:
+  call void @foo()
+  ret void
+}
+
+
+; make sure that bl 0 <foo> (fff7feff) is correctly encoded
+; CHECK: '_section_data', '70470000 2de90048 fff7feff bde80088'
+
+;  Offset     Info    Type            Sym.Value  Sym. Name
+; 00000008  0000070a R_ARM_THM_CALL    00000001   foo
+; CHECK:           Relocation 0x00000000 
+; CHECK-NEXT:      'r_offset', 0x00000008
+; CHECK-NEXT:      'r_sym', 0x00000007
+; CHECK-NEXT:      'r_type', 0x0000000a
+
+; make sure foo is thumb function: bit 0 = 1
+; CHECK:           Symbol 0x00000007
+; CHECK-NEXT:      'foo'
+; CHECK-NEXT:      'st_value', 0x00000001