[llvm] r187019 - [mips] Use pristine object file while processing relocations.

[Akira Hatanaka]

Author: ahatanak
Date: Tue Jul 23 20:58:40 2013
New Revision: 187019

URL: http://llvm.org/viewvc/llvm-project?rev=187019&view=rev
Log:
[mips] Use pristine object file while processing relocations.

    Similar to ARM change r182800, dynamic linker will read bits/addends from
    the original object rather than from the object that might have been patched
    previously. For the purpose of relocations for MCJIT stubs on MIPS, we
    internally use otherwise unused MIPS relocations.
    
    The change also enables MCJIT unit tests for MIPS (EL/BE), and the following
    two tests now pass:
    
    - MCJITTest.return_global and
    - MCJITTest.multiple_functions.
    
    These issues have been tracked as Bug 16250.

    Patch by Petar Jovanovic.


Modified:
    llvm/trunk/include/llvm/Object/ELF.h
    llvm/trunk/include/llvm/Support/ELF.h
    llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
    llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTestBase.h

Modified: llvm/trunk/include/llvm/Object/ELF.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/ELF.h?rev=187019&r1=187018&r2=187019&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Object/ELF.h (original)
+++ llvm/trunk/include/llvm/Object/ELF.h Tue Jul 23 20:58:40 2013
@@ -1666,6 +1666,8 @@ StringRef ELFObjectFile<ELFT>::getReloca
       LLVM_ELF_SWITCH_RELOC_TYPE_NAME(R_MIPS_PC16);
       LLVM_ELF_SWITCH_RELOC_TYPE_NAME(R_MIPS_CALL16);
       LLVM_ELF_SWITCH_RELOC_TYPE_NAME(R_MIPS_GPREL32);
+      LLVM_ELF_SWITCH_RELOC_TYPE_NAME(R_MIPS_UNUSED1);
+      LLVM_ELF_SWITCH_RELOC_TYPE_NAME(R_MIPS_UNUSED2);
       LLVM_ELF_SWITCH_RELOC_TYPE_NAME(R_MIPS_SHIFT5);
       LLVM_ELF_SWITCH_RELOC_TYPE_NAME(R_MIPS_SHIFT6);
       LLVM_ELF_SWITCH_RELOC_TYPE_NAME(R_MIPS_64);

Modified: llvm/trunk/include/llvm/Support/ELF.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/ELF.h?rev=187019&r1=187018&r2=187019&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/ELF.h (original)
+++ llvm/trunk/include/llvm/Support/ELF.h Tue Jul 23 20:58:40 2013
@@ -868,6 +868,8 @@ enum {
   R_MIPS_PC16              = 10,
   R_MIPS_CALL16            = 11,
   R_MIPS_GPREL32           = 12,
+  R_MIPS_UNUSED1           = 13,
+  R_MIPS_UNUSED2           = 14,
   R_MIPS_SHIFT5            = 16,
   R_MIPS_SHIFT6            = 17,
   R_MIPS_64                = 18,

Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp?rev=187019&r1=187018&r2=187019&view=diff
==============================================================================
--- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp (original)
+++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp Tue Jul 23 20:58:40 2013
@@ -456,6 +456,8 @@ void RuntimeDyldELF::resolveMIPSRelocati
                                            uint32_t Value,
                                            uint32_t Type,
                                            int32_t Addend) {
+  uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress +
+                                                      Offset);
   uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset);
   Value += Addend;
 
@@ -473,19 +475,30 @@ void RuntimeDyldELF::resolveMIPSRelocati
     llvm_unreachable("Not implemented relocation type!");
     break;
   case ELF::R_MIPS_32:
-    *TargetPtr = Value + (*TargetPtr);
+    *TargetPtr = Value + (*Placeholder);
     break;
   case ELF::R_MIPS_26:
-    *TargetPtr = ((*TargetPtr) & 0xfc000000) | (( Value & 0x0fffffff) >> 2);
+    *TargetPtr = ((*Placeholder) & 0xfc000000) | (( Value & 0x0fffffff) >> 2);
     break;
   case ELF::R_MIPS_HI16:
     // Get the higher 16-bits. Also add 1 if bit 15 is 1.
-    Value += ((*TargetPtr) & 0x0000ffff) << 16;
+    Value += ((*Placeholder) & 0x0000ffff) << 16;
+    *TargetPtr = ((*Placeholder) & 0xffff0000) |
+                 (((Value + 0x8000) >> 16) & 0xffff);
+    break;
+  case ELF::R_MIPS_LO16:
+    Value += ((*Placeholder) & 0x0000ffff);
+    *TargetPtr = ((*Placeholder) & 0xffff0000) | (Value & 0xffff);
+    break;
+  case ELF::R_MIPS_UNUSED1:
+    // Similar to ELF::R_ARM_PRIVATE_0, R_MIPS_UNUSED1 and R_MIPS_UNUSED2
+    // are used for internal JIT purpose. These relocations are similar to
+    // R_MIPS_HI16 and R_MIPS_LO16, but they do not take any addend into
+    // account.
     *TargetPtr = ((*TargetPtr) & 0xffff0000) |
                  (((Value + 0x8000) >> 16) & 0xffff);
     break;
-   case ELF::R_MIPS_LO16:
-    Value += ((*TargetPtr) & 0x0000ffff);
+  case ELF::R_MIPS_UNUSED2:
     *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff);
     break;
    }
@@ -954,10 +967,10 @@ void RuntimeDyldELF::processRelocationRe
       // Creating Hi and Lo relocations for the filled stub instructions.
       RelocationEntry REHi(SectionID,
                            StubTargetAddr - Section.Address,
-                           ELF::R_MIPS_HI16, Value.Addend);
+                           ELF::R_MIPS_UNUSED1, Value.Addend);
       RelocationEntry RELo(SectionID,
                            StubTargetAddr - Section.Address + 4,
-                           ELF::R_MIPS_LO16, Value.Addend);
+                           ELF::R_MIPS_UNUSED2, Value.Addend);
 
       if (Value.SymbolName) {
         addRelocationForSymbol(REHi, Value.SymbolName);

Modified: llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTestBase.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTestBase.h?rev=187019&r1=187018&r2=187019&view=diff
==============================================================================
--- llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTestBase.h (original)
+++ llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTestBase.h Tue Jul 23 20:58:40 2013
@@ -156,6 +156,8 @@ protected:
     // kept in sync.
     SupportedArchs.push_back(Triple::aarch64);
     SupportedArchs.push_back(Triple::arm);
+    SupportedArchs.push_back(Triple::mips);
+    SupportedArchs.push_back(Triple::mipsel);
     SupportedArchs.push_back(Triple::x86);
     SupportedArchs.push_back(Triple::x86_64);