From b889e0cd2fea4afee623d5be603b912b955a2eca Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatanaka@mips.com>
Date: Fri, 17 Aug 2012 21:28:04 +0000
Subject: Correct MCJIT functionality for MIPS32 architecture.

No new tests are added.
All tests in ExecutionEngine/MCJIT that have been failing pass after this patch
is applied (when "make check" is done on a mips board).

Patch by Petar Jovanovic.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162135 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp    | 27 +++++--
 lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp | 91 ++++++++++++++++++++++
 lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h   |  6 ++
 lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h  |  2 +
 4 files changed, 121 insertions(+), 5 deletions(-)

(limited to 'lib/ExecutionEngine')

diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index b4640404f6..a98ddc0e12 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -108,7 +108,8 @@ bool RuntimeDyldImpl::loadObject(const MemoryBuffer *InputBuffer) {
       CommonSymbols[*i] = Size;
     } else {
       if (SymType == object::SymbolRef::ST_Function ||
-          SymType == object::SymbolRef::ST_Data) {
+          SymType == object::SymbolRef::ST_Data ||
+          SymType == object::SymbolRef::ST_Unknown) {
         uint64_t FileOffset;
         StringRef SectionData;
         section_iterator si = obj->end_sections();
@@ -333,15 +334,31 @@ void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
 }
 
 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr) {
-  // TODO: There is only ARM far stub now. We should add the Thumb stub,
-  // and stubs for branches Thumb - ARM and ARM - Thumb.
   if (Arch == Triple::arm) {
+    // TODO: There is only ARM far stub now. We should add the Thumb stub,
+    // and stubs for branches Thumb - ARM and ARM - Thumb.
     uint32_t *StubAddr = (uint32_t*)Addr;
     *StubAddr = 0xe51ff004; // ldr pc,<label>
     return (uint8_t*)++StubAddr;
-  }
-  else
+  } else if (Arch == Triple::mipsel) {
+    uint32_t *StubAddr = (uint32_t*)Addr;
+    // 0:   3c190000        lui     t9,%hi(addr).
+    // 4:   27390000        addiu   t9,t9,%lo(addr).
+    // 8:   03200008        jr      t9.
+    // c:   00000000        nop.
+    const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
+    const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
+
+    *StubAddr = LuiT9Instr;
+    StubAddr++;
+    *StubAddr = AdduiT9Instr;
+    StubAddr++;
+    *StubAddr = JrT9Instr;
+    StubAddr++;
+    *StubAddr = NopInstr;
     return Addr;
+  }
+  return Addr;
 }
 
 // Assign an address to a symbol name and resolve all the relocations
diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
index 75bb586ef2..67166c919b 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
@@ -306,6 +306,44 @@ void RuntimeDyldELF::resolveARMRelocation(uint8_t *LocalAddress,
   }
 }
 
+void RuntimeDyldELF::resolveMIPSRelocation(uint8_t *LocalAddress,
+                                          uint32_t FinalAddress,
+                                          uint32_t Value,
+                                          uint32_t Type,
+                                          int32_t Addend) {
+  uint32_t* TargetPtr = (uint32_t*)LocalAddress;
+  Value += Addend;
+
+  DEBUG(dbgs() << "resolveMipselocation, LocalAddress: " << LocalAddress
+               << " FinalAddress: " << format("%p",FinalAddress)
+               << " Value: " << format("%x",Value)
+               << " Type: " << format("%x",Type)
+               << " Addend: " << format("%x",Addend)
+               << "\n");
+
+  switch(Type) {
+  default:
+    llvm_unreachable("Not implemented relocation type!");
+    break;
+  case ELF::R_MIPS_32:
+    *TargetPtr = Value + (*TargetPtr);
+    break;
+  case ELF::R_MIPS_26:
+    *TargetPtr = ((*TargetPtr) & 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;
+    *TargetPtr = ((*TargetPtr) & 0xffff0000) |
+                 (((Value + 0x8000) >> 16) & 0xffff);
+    break;
+   case ELF::R_MIPS_LO16:
+    Value += ((*TargetPtr) & 0x0000ffff);
+    *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff);
+    break;
+   }
+}
+
 void RuntimeDyldELF::resolveRelocation(uint8_t *LocalAddress,
                                        uint64_t FinalAddress,
                                        uint64_t Value,
@@ -326,6 +364,12 @@ void RuntimeDyldELF::resolveRelocation(uint8_t *LocalAddress,
                          (uint32_t)(Value & 0xffffffffL), Type,
                          (uint32_t)(Addend & 0xffffffffL));
     break;
+  case Triple::mips:    // Fall through.
+  case Triple::mipsel:
+    resolveMIPSRelocation(LocalAddress, (uint32_t)(FinalAddress & 0xffffffffL),
+                         (uint32_t)(Value & 0xffffffffL), Type,
+                         (uint32_t)(Addend & 0xffffffffL));
+    break;
   default: llvm_unreachable("Unsupported CPU type!");
   }
 }
@@ -423,6 +467,53 @@ void RuntimeDyldELF::processRelocationRef(const ObjRelocationInfo &Rel,
                         Section.StubOffset, RelType, 0);
       Section.StubOffset += getMaxStubSize();
     }
+  } else if (Arch == Triple::mipsel && RelType == ELF::R_MIPS_26) {
+    // This is an Mips branch relocation, need to use a stub function.
+    DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
+    SectionEntry &Section = Sections[Rel.SectionID];
+    uint8_t *Target = Section.Address + Rel.Offset;
+    uint32_t *TargetAddress = (uint32_t *)Target;
+
+    // Extract the addend from the instruction.
+    uint32_t Addend = ((*TargetAddress) & 0x03ffffff) << 2;
+
+    Value.Addend += Addend;
+
+    //  Look up for existing stub.
+    StubMap::const_iterator i = Stubs.find(Value);
+    if (i != Stubs.end()) {
+      resolveRelocation(Target, (uint64_t)Target,
+                        (uint64_t)Section.Address +
+                        i->second, RelType, 0);
+      DEBUG(dbgs() << " Stub function found\n");
+    } else {
+      // Create a new stub function.
+      DEBUG(dbgs() << " Create a new stub function\n");
+      Stubs[Value] = Section.StubOffset;
+      uint8_t *StubTargetAddr = createStubFunction(Section.Address +
+                                                   Section.StubOffset);
+
+      // Creating Hi and Lo relocations for the filled stub instructions.
+      RelocationEntry REHi(Rel.SectionID,
+                           StubTargetAddr - Section.Address,
+                           ELF::R_MIPS_HI16, Value.Addend);
+      RelocationEntry RELo(Rel.SectionID,
+                           StubTargetAddr - Section.Address + 4,
+                           ELF::R_MIPS_LO16, Value.Addend);
+
+      if (Value.SymbolName) {
+        addRelocationForSymbol(REHi, Value.SymbolName);
+        addRelocationForSymbol(RELo, Value.SymbolName);
+      } else {
+        addRelocationForSection(REHi, Value.SectionID);
+        addRelocationForSection(RELo, Value.SectionID);
+      }
+
+      resolveRelocation(Target, (uint64_t)Target,
+                        (uint64_t)Section.Address +
+                        Section.StubOffset, RelType, 0);
+      Section.StubOffset += getMaxStubSize();
+    }
   } else {
     RelocationEntry RE(Rel.SectionID, Rel.Offset, RelType, Value.Addend);
     if (Value.SymbolName)
diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
index e413f780f5..68633c847c 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
@@ -42,6 +42,12 @@ protected:
                             uint32_t Type,
                             int32_t Addend);
 
+  void resolveMIPSRelocation(uint8_t *LocalAddress,
+                            uint32_t FinalAddress,
+                            uint32_t Value,
+                            uint32_t Type,
+                            int32_t Addend);
+
   virtual void resolveRelocation(uint8_t *LocalAddress,
                                  uint64_t FinalAddress,
                                  uint64_t Value,
diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
index c38ca696f2..3d8999437c 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
@@ -161,6 +161,8 @@ protected:
   inline unsigned getMaxStubSize() {
     if (Arch == Triple::arm || Arch == Triple::thumb)
       return 8; // 32-bit instruction and 32-bit address
+    else if (Arch == Triple::mipsel)
+      return 16;
     else
       return 0;
   }
-- 
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