From 2ccf148fbaaf9ea15233d7ef09e31ca0fa6ee3be Mon Sep 17 00:00:00 2001
From: Jason W Kim <jason.w.kim.2009@gmail.com>
Date: Fri, 3 Dec 2010 19:40:23 +0000
Subject: [PATCH] fix ARM::fixup_arm_branch, cleanup, and share more code
 between ELF and Darwin

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120832 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMAsmBackend.cpp | 35 ++++++++++----------------------
 1 file changed, 11 insertions(+), 24 deletions(-)

diff --git a/lib/Target/ARM/ARMAsmBackend.cpp b/lib/Target/ARM/ARMAsmBackend.cpp
index eb03a24b026..8c5cab72750 100644
--- a/lib/Target/ARM/ARMAsmBackend.cpp
+++ b/lib/Target/ARM/ARMAsmBackend.cpp
@@ -65,9 +65,16 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
   default:
     llvm_unreachable("Unknown fixup kind!");
   case FK_Data_4:
-  case ARM::fixup_arm_movt_hi16:
-  case ARM::fixup_arm_movw_lo16:
     return Value;
+  case ARM::fixup_arm_movt_hi16:
+  case ARM::fixup_arm_movw_lo16: {
+    unsigned Hi4 = (Value & 0xF000) >> 12;
+    unsigned Lo12 = Value & 0x0FFF;
+    // inst{19-16} = Hi4;
+    // inst{11-0} = Lo12;
+    Value = (Hi4 << 16) | (Lo12);
+    return Value;
+  }
   case ARM::fixup_arm_ldst_pcrel_12: {
     bool isAdd = true;
     // ARM PC-relative values are offset by 8.
@@ -96,7 +103,7 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
   case ARM::fixup_arm_branch:
     // These values don't encode the low two bits since they're always zero.
     // Offset by 8 just as above.
-    return (Value - 8) >> 2;
+    return 0xFFFFFF & ((Value - 8) >> 2);
   case ARM::fixup_arm_pcrel_10: {
     // Offset by 8 just as above.
     Value = Value - 8;
@@ -142,7 +149,7 @@ public:
   }
 };
 
-// Fixme: can we raise this to share code between Darwin and ELF?
+// Fixme: Raise this to share code between Darwin and ELF.
 void ELFARMAsmBackend::ApplyFixup(const MCFixup &Fixup, MCDataFragment &DF,
                                   uint64_t Value) const {
   uint32_t Mask = 0;
@@ -150,32 +157,12 @@ void ELFARMAsmBackend::ApplyFixup(const MCFixup &Fixup, MCDataFragment &DF,
   unsigned NumBytes = 4;
   Value = adjustFixupValue(Fixup.getKind(), Value);
 
-  switch (Fixup.getKind()) {
-  default: assert(0 && "Unsupported Fixup kind"); break;
-  case ARM::fixup_arm_branch: {
-    unsigned Lo24 = Value & 0xFFFFFF;
-    Mask = ~(0xFFFFFF);
-    Value = Lo24;
-  }; break;
-  case ARM::fixup_arm_movt_hi16:
-  case ARM::fixup_arm_movw_lo16: {
-    unsigned Hi4 = (Value & 0xF000) >> 12;
-    unsigned Lo12 = Value & 0x0FFF;
-    // inst{19-16} = Hi4;
-    // inst{11-0} = Lo12;
-    Value = (Hi4 << 16) | (Lo12);
-    Mask = ~(0xF0FFF);
-  }; break;
-  }
-
   assert((Fixup.getOffset() % NumBytes == 0)
          && "Offset mod NumBytes is nonzero!");
   // For each byte of the fragment that the fixup touches, mask in the
   // bits from the fixup value.
   // The Value has been "split up" into the appropriate bitfields above.
-  // Fixme: how to share code with the .td generated code?
   for (unsigned i = 0; i != NumBytes; ++i) {
-    DF.getContents()[Fixup.getOffset() + i] &= uint8_t(Mask >> (i * 8));
     DF.getContents()[Fixup.getOffset() + i] |= uint8_t(Value >> (i * 8));
   }
 }