From: Sagar Thakur <sagar.thakur@imgtec.com>
Date: Thu, 22 Jun 2017 11:49:19 +0000 (+0000)
Subject: [mips] Adds support for R_MIPS_26, HIGHER, HIGHEST relocations in RuntimeDyld
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9410186031e328801121250ad51ad551c04c2d2b;p=llvm

[mips] Adds support for R_MIPS_26, HIGHER, HIGHEST relocations in RuntimeDyld

After the N64 static relocation model support was added to llvm it is required to add its support in RuntimeDyld also because lldb uses ExecutionEngine for evaluating expressions.

Reviewed by sdardis
Differential: D31649


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305997 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index 2b69f1a0269..d047697583a 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -861,7 +861,7 @@ uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
     // and stubs for branches Thumb - ARM and ARM - Thumb.
     writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
     return Addr + 4;
-  } else if (IsMipsO32ABI) {
+  } else if (IsMipsO32ABI || IsMipsN32ABI) {
     // 0:   3c190000        lui     t9,%hi(addr).
     // 4:   27390000        addiu   t9,t9,%lo(addr).
     // 8:   03200008        jr      t9.
@@ -869,13 +869,39 @@ uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
     const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
     const unsigned NopInstr = 0x0;
     unsigned JrT9Instr = 0x03200008;
-    if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_32R6)
-        JrT9Instr = 0x03200009;
+    if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_32R6 ||
+        (AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
+      JrT9Instr = 0x03200009;
 
     writeBytesUnaligned(LuiT9Instr, Addr, 4);
-    writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
-    writeBytesUnaligned(JrT9Instr, Addr+8, 4);
-    writeBytesUnaligned(NopInstr, Addr+12, 4);
+    writeBytesUnaligned(AdduiT9Instr, Addr + 4, 4);
+    writeBytesUnaligned(JrT9Instr, Addr + 8, 4);
+    writeBytesUnaligned(NopInstr, Addr + 12, 4);
+    return Addr;
+  } else if (IsMipsN64ABI) {
+    // 0:   3c190000        lui     t9,%highest(addr).
+    // 4:   67390000        daddiu  t9,t9,%higher(addr).
+    // 8:   0019CC38        dsll    t9,t9,16.
+    // c:   67390000        daddiu  t9,t9,%hi(addr).
+    // 10:  0019CC38        dsll    t9,t9,16.
+    // 14:  67390000        daddiu  t9,t9,%lo(addr).
+    // 18:  03200008        jr      t9.
+    // 1c:  00000000        nop.
+    const unsigned LuiT9Instr = 0x3c190000, DaddiuT9Instr = 0x67390000,
+                   DsllT9Instr = 0x19CC38;
+    const unsigned NopInstr = 0x0;
+    unsigned JrT9Instr = 0x03200008;
+    if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
+      JrT9Instr = 0x03200009;
+
+    writeBytesUnaligned(LuiT9Instr, Addr, 4);
+    writeBytesUnaligned(DaddiuT9Instr, Addr + 4, 4);
+    writeBytesUnaligned(DsllT9Instr, Addr + 8, 4);
+    writeBytesUnaligned(DaddiuT9Instr, Addr + 12, 4);
+    writeBytesUnaligned(DsllT9Instr, Addr + 16, 4);
+    writeBytesUnaligned(DaddiuT9Instr, Addr + 20, 4);
+    writeBytesUnaligned(JrT9Instr, Addr + 24, 4);
+    writeBytesUnaligned(NopInstr, Addr + 28, 4);
     return Addr;
   } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
     // Depending on which version of the ELF ABI is in use, we need to
diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
index 3d12eadea4d..652e90922e4 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
@@ -1251,8 +1251,7 @@ RuntimeDyldELF::processRelocationRef(
         if (Value.SymbolName) {
           addRelocationForSymbol(REHi, Value.SymbolName);
           addRelocationForSymbol(RELo, Value.SymbolName);
-        }
-        else {
+        } else {
           addRelocationForSection(REHi, Value.SectionID);
           addRelocationForSection(RELo, Value.SectionID);
         }
@@ -1301,10 +1300,14 @@ RuntimeDyldELF::processRelocationRef(
       processSimpleRelocation(SectionID, Offset, RelType, Value);
     }
   } else if (IsMipsN32ABI || IsMipsN64ABI) {
+    uint8_t *Placeholder = reinterpret_cast<uint8_t *>(
+        computePlaceholderAddress(SectionID, Offset));
+    uint32_t Opcode = readBytesUnaligned(Placeholder, 4);
+
     uint32_t r_type = RelType & 0xff;
     RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
-    if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE
-        || r_type == ELF::R_MIPS_GOT_DISP) {
+    if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE ||
+        r_type == ELF::R_MIPS_GOT_DISP) {
       StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName);
       if (i != GOTSymbolOffsets.end())
         RE.SymOffset = i->second;
@@ -1312,11 +1315,83 @@ RuntimeDyldELF::processRelocationRef(
         RE.SymOffset = allocateGOTEntries(1);
         GOTSymbolOffsets[TargetName] = RE.SymOffset;
       }
+      if (Value.SymbolName)
+        addRelocationForSymbol(RE, Value.SymbolName);
+      else
+        addRelocationForSection(RE, Value.SectionID);
+    } else if (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[SectionID];
+
+      //  Look up for existing stub.
+      StubMap::const_iterator i = Stubs.find(Value);
+      if (i != Stubs.end()) {
+        RelocationEntry RE(SectionID, Offset, RelType, i->second);
+        addRelocationForSection(RE, SectionID);
+        DEBUG(dbgs() << " Stub function found\n");
+      } else {
+        // Create a new stub function.
+        DEBUG(dbgs() << " Create a new stub function\n");
+        Stubs[Value] = Section.getStubOffset();
+
+        unsigned AbiVariant;
+        O.getPlatformFlags(AbiVariant);
+
+        uint8_t *StubTargetAddr = createStubFunction(
+            Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant);
+
+        if (IsMipsN32ABI) {
+          // Creating Hi and Lo relocations for the filled stub instructions.
+          RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(),
+                               ELF::R_MIPS_HI16, Value.Addend);
+          RelocationEntry RELo(SectionID,
+                               StubTargetAddr - Section.getAddress() + 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);
+          }
+        } else {
+          // Creating Highest, Higher, Hi and Lo relocations for the filled stub
+          // instructions.
+          RelocationEntry REHighest(SectionID,
+                                    StubTargetAddr - Section.getAddress(),
+                                    ELF::R_MIPS_HIGHEST, Value.Addend);
+          RelocationEntry REHigher(SectionID,
+                                   StubTargetAddr - Section.getAddress() + 4,
+                                   ELF::R_MIPS_HIGHER, Value.Addend);
+          RelocationEntry REHi(SectionID,
+                               StubTargetAddr - Section.getAddress() + 12,
+                               ELF::R_MIPS_HI16, Value.Addend);
+          RelocationEntry RELo(SectionID,
+                               StubTargetAddr - Section.getAddress() + 20,
+                               ELF::R_MIPS_LO16, Value.Addend);
+          if (Value.SymbolName) {
+            addRelocationForSymbol(REHighest, Value.SymbolName);
+            addRelocationForSymbol(REHigher, Value.SymbolName);
+            addRelocationForSymbol(REHi, Value.SymbolName);
+            addRelocationForSymbol(RELo, Value.SymbolName);
+          } else {
+            addRelocationForSection(REHighest, Value.SectionID);
+            addRelocationForSection(REHigher, Value.SectionID);
+            addRelocationForSection(REHi, Value.SectionID);
+            addRelocationForSection(RELo, Value.SectionID);
+          }
+        }
+        RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset());
+        addRelocationForSection(RE, SectionID);
+        Section.advanceStubOffset(getMaxStubSize());
+      }
+    } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16 ||
+               RelType == ELF::R_MIPS_HIGHEST ||
+               RelType == ELF::R_MIPS_HIGHER || RelType == ELF::R_MIPS_LO16 ||
+               RelType == ELF::R_MIPS_PCLO16) {
+      processSimpleRelocation(SectionID, Offset, RelType, Value);
     }
-    if (Value.SymbolName)
-      addRelocationForSymbol(RE, Value.SymbolName);
-    else
-      addRelocationForSection(RE, Value.SectionID);
   } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
     if (RelType == ELF::R_PPC64_REL24) {
       // Determine ABI variant in use for this object.
diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
index fb5da6dd8bb..f37bd0bbaea 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
@@ -66,8 +66,10 @@ class RuntimeDyldELF : public RuntimeDyldImpl {
       return 20; // movz; movk; movk; movk; br
     if (Arch == Triple::arm || Arch == Triple::thumb)
       return 8; // 32-bit instruction and 32-bit address
-    else if (IsMipsO32ABI)
+    else if (IsMipsO32ABI || IsMipsN32ABI)
       return 16;
+    else if (IsMipsN64ABI)
+      return 32;
     else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le)
       return 44;
     else if (Arch == Triple::x86_64)
diff --git a/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldELFMips.cpp b/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldELFMips.cpp
index 926996d6f7b..fdca0ce4f3c 100644
--- a/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldELFMips.cpp
+++ b/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldELFMips.cpp
@@ -141,6 +141,10 @@ int64_t RuntimeDyldELFMips::evaluateMIPS64Relocation(
     return ((Value + Addend + 0x8000) >> 16) & 0xffff;
   case ELF::R_MIPS_LO16:
     return (Value + Addend) & 0xffff;
+  case ELF::R_MIPS_HIGHER:
+    return ((Value + Addend + 0x80008000) >> 32) & 0xffff;
+  case ELF::R_MIPS_HIGHEST:
+    return ((Value + Addend + 0x800080008000) >> 48) & 0xffff;
   case ELF::R_MIPS_CALL16:
   case ELF::R_MIPS_GOT_DISP:
   case ELF::R_MIPS_GOT_PAGE: {
@@ -215,6 +219,8 @@ void RuntimeDyldELFMips::applyMIPSRelocation(uint8_t *TargetPtr, int64_t Value,
   case ELF::R_MIPS_GPREL16:
   case ELF::R_MIPS_HI16:
   case ELF::R_MIPS_LO16:
+  case ELF::R_MIPS_HIGHER:
+  case ELF::R_MIPS_HIGHEST:
   case ELF::R_MIPS_PC16:
   case ELF::R_MIPS_PCHI16:
   case ELF::R_MIPS_PCLO16: