[ELF2][MIPS] Support R_MIPS_CALL16 relocation

atanasyan · atanasyan · commit 96306bbebc92 · 2015-11-25T20:58:52.000Z
R_MIPS_CALL16 relocation provides the same result as R_MIPS_GOT16 relocation but does not need to check the result on overflow. Differential Revision: http://reviews.llvm.org/D14916 llvm-svn: 254092
diff --git a/lld/ELF/Target.cpp b/lld/ELF/Target.cpp
@@ -116,6 +116,7 @@ class AArch64TargetInfo final : public TargetInfo {
 template <class ELFT> class MipsTargetInfo final : public TargetInfo {
 public:
   MipsTargetInfo();
+  unsigned getGotRefReloc(unsigned Type) const override;
   void writeGotHeaderEntries(uint8_t *Buf) const override;
   void writeGotPltEntry(uint8_t *Buf, uint64_t Plt) const override;
   void writePltZeroEntry(uint8_t *Buf, uint64_t GotEntryAddr,
@@ -875,6 +876,11 @@ template <class ELFT> MipsTargetInfo<ELFT>::MipsTargetInfo() {
   GotHeaderEntriesNum = 2;
 }
 
+template <class ELFT>
+unsigned MipsTargetInfo<ELFT>::getGotRefReloc(unsigned Type) const {
+  return Type;
+}
+
 template <class ELFT>
 void MipsTargetInfo<ELFT>::writeGotHeaderEntries(uint8_t *Buf) const {
   typedef typename llvm::object::ELFFile<ELFT>::Elf_Off Elf_Off;
@@ -895,7 +901,7 @@ void MipsTargetInfo<ELFT>::writePltEntry(uint8_t *Buf, uint64_t GotEntryAddr,
 template <class ELFT>
 bool MipsTargetInfo<ELFT>::relocNeedsGot(uint32_t Type,
                                          const SymbolBody &S) const {
-  return Type == R_MIPS_GOT16;
+  return Type == R_MIPS_GOT16 || Type == R_MIPS_CALL16;
 }
 
 template <class ELFT>
@@ -913,9 +919,10 @@ void MipsTargetInfo<ELFT>::relocateOne(uint8_t *Loc, uint8_t *BufEnd,
   case R_MIPS_32:
     add32<E>(Loc, SA);
     break;
+  case R_MIPS_CALL16:
   case R_MIPS_GOT16: {
     int64_t V = SA - getMipsGpAddr<ELFT>();
-    if (!isInt<16>(V))
+    if (Type == R_MIPS_GOT16 && !isInt<16>(V))
       error("Relocation R_MIPS_GOT16 out of range");
     write32<E>(Loc, (read32<E>(Loc) & 0xffff0000) | (V & 0xffff));
     break;
diff --git a/lld/test/ELF/mips-call16.s b/lld/test/ELF/mips-call16.s
@@ -0,0 +1,40 @@
+# Check R_MIPS_CALL16 relocation calculation.
+
+# RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux %s -o %t.o
+# RUN: ld.lld %t.o -shared -o %t.exe
+# RUN: llvm-objdump -d %t.exe | FileCheck %s
+# RUN: llvm-readobj -mips-plt-got -symbols %t.exe \
+# RUN:   | FileCheck -check-prefix=GOT %s
+
+# REQUIRES: mips
+
+  .text
+  .globl  __start
+__start:
+  lw      $t0,%call16(g1)($gp)
+
+  .globl g1
+  .type  g1,@function
+g1:
+  nop
+
+# CHECK:      Disassembly of section .text:
+# CHECK-NEXT: __start:
+# CHECK-NEXT:      10000:   8f 88 80 18   lw   $8, -32744
+
+# GOT:      Name: g1
+# GOT-NEXT: Value: 0x[[ADDR:[0-9A-F]+]]
+
+# GOT:      Local entries [
+# GOT-NEXT: ]
+# GOT-NEXT: Global entries [
+# GOT-NEXT:   Entry {
+# GOT-NEXT:     Address:
+# GOT-NEXT:     Access: -32744
+# GOT-NEXT:     Initial: 0x[[ADDR]]
+# GOT-NEXT:     Value: 0x[[ADDR]]
+# GOT-NEXT:     Type: Function
+# GOT-NEXT:     Section: .text
+# GOT-NEXT:     Name: g1
+# GOT-NEXT:   }
+# GOT-NEXT: ]
