From 47f84b1a3cb2bf9335d9a68d8528babed0dbba9f Mon Sep 17 00:00:00 2001
From: George Rimar <grimar@accesssoftek.com>
Date: Thu, 18 May 2017 08:25:11 +0000
Subject: [PATCH] [DWARF] - Simplify RelocVisitor implementation.

We do not need to store relocation width field.
Patch removes relative code, that simplifies implementation.

Differential revision: https://reviews.llvm.org/D33274

llvm-svn: 303335
---
 llvm/include/llvm/DebugInfo/DWARF/DWARFRelocMap.h |   2 +-
 llvm/include/llvm/Object/RelocVisitor.h           | 231 +++++++++-------------
 llvm/lib/DebugInfo/DWARF/DWARFContext.cpp         |   4 +-
 3 files changed, 99 insertions(+), 138 deletions(-)

diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFRelocMap.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFRelocMap.h
index ec0397a..fabacc0 100644
--- a/llvm/include/llvm/DebugInfo/DWARF/DWARFRelocMap.h
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFRelocMap.h
@@ -17,7 +17,7 @@
 namespace llvm {
 
 struct RelocAddrEntry {
-  int64_t Value;
+  uint64_t Value;
 };
 
 /// In place of applying the relocations to the data we've read from disk we use
diff --git a/llvm/include/llvm/Object/RelocVisitor.h b/llvm/include/llvm/Object/RelocVisitor.h
index 73c7ce3..86579b7 100644
--- a/llvm/include/llvm/Object/RelocVisitor.h
+++ b/llvm/include/llvm/Object/RelocVisitor.h
@@ -32,18 +32,6 @@
 namespace llvm {
 namespace object {
 
-struct RelocToApply {
-  // The computed value after applying the relevant relocations.
-  int64_t Value = 0;
-
-  // The width of the value; how many bytes to touch when applying the
-  // relocation.
-  char Width = 0;
-
-  RelocToApply() = default;
-  RelocToApply(int64_t Value, char Width) : Value(Value), Width(Width) {}
-};
-
 /// @brief Base class for object file relocation visitors.
 class RelocVisitor {
 public:
@@ -52,7 +40,7 @@ public:
   // TODO: Should handle multiple applied relocations via either passing in the
   // previously computed value or just count paired relocations as a single
   // visit.
-  RelocToApply visit(uint32_t RelocType, RelocationRef R, uint64_t Value = 0) {
+  uint64_t visit(uint32_t RelocType, RelocationRef R, uint64_t Value = 0) {
     if (isa<ELFObjectFileBase>(ObjToVisit))
       return visitELF(RelocType, R, Value);
     if (isa<COFFObjectFile>(ObjToVisit))
@@ -61,7 +49,7 @@ public:
       return visitMachO(RelocType, R, Value);
 
     HasError = true;
-    return RelocToApply();
+    return 0;
   }
 
   bool error() { return HasError; }
@@ -70,7 +58,7 @@ private:
   const ObjectFile &ObjToVisit;
   bool HasError = false;
 
-  RelocToApply visitELF(uint32_t RelocType, RelocationRef R, uint64_t Value) {
+  uint64_t visitELF(uint32_t RelocType, RelocationRef R, uint64_t Value) {
     if (ObjToVisit.getBytesInAddress() == 8) { // 64-bit object file
       switch (ObjToVisit.getArch()) {
       case Triple::x86_64:
@@ -87,7 +75,7 @@ private:
           return visitELF_X86_64_32S(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::aarch64:
       case Triple::aarch64_be:
@@ -98,7 +86,7 @@ private:
           return visitELF_AARCH64_ABS64(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::bpfel:
       case Triple::bpfeb:
@@ -109,7 +97,7 @@ private:
           return visitELF_BPF_64_32(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::mips64el:
       case Triple::mips64:
@@ -120,7 +108,7 @@ private:
           return visitELF_MIPS64_64(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::ppc64le:
       case Triple::ppc64:
@@ -131,7 +119,7 @@ private:
           return visitELF_PPC64_ADDR64(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::systemz:
         switch (RelocType) {
@@ -141,7 +129,7 @@ private:
           return visitELF_390_64(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::sparcv9:
         switch (RelocType) {
@@ -153,7 +141,7 @@ private:
           return visitELF_SPARCV9_64(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::amdgcn:
         switch (RelocType) {
@@ -163,11 +151,11 @@ private:
           return visitELF_AMDGPU_ABS64(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       default:
         HasError = true;
-        return RelocToApply();
+        return 0;
       }
     } else if (ObjToVisit.getBytesInAddress() == 4) { // 32-bit object file
       switch (ObjToVisit.getArch()) {
@@ -181,7 +169,7 @@ private:
           return visitELF_386_PC32(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::ppc:
         switch (RelocType) {
@@ -189,14 +177,14 @@ private:
           return visitELF_PPC_ADDR32(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::arm:
       case Triple::armeb:
         switch (RelocType) {
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         case ELF::R_ARM_ABS32:
           return visitELF_ARM_ABS32(R, Value);
         }
@@ -206,7 +194,7 @@ private:
           return visitELF_Lanai_32(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::mipsel:
       case Triple::mips:
@@ -215,7 +203,7 @@ private:
           return visitELF_MIPS_32(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::sparc:
         switch (RelocType) {
@@ -224,7 +212,7 @@ private:
           return visitELF_SPARC_32(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       case Triple::hexagon:
         switch (RelocType) {
@@ -232,18 +220,18 @@ private:
           return visitELF_HEX_32(R, Value);
         default:
           HasError = true;
-          return RelocToApply();
+          return 0;
         }
       default:
         HasError = true;
-        return RelocToApply();
+        return 0;
       }
     } else {
       report_fatal_error("Invalid word size in object file");
     }
   }
 
-  RelocToApply visitCOFF(uint32_t RelocType, RelocationRef R, uint64_t Value) {
+  uint64_t visitCOFF(uint32_t RelocType, RelocationRef R, uint64_t Value) {
     switch (ObjToVisit.getArch()) {
     case Triple::x86:
       switch (RelocType) {
@@ -263,10 +251,10 @@ private:
       break;
     }
     HasError = true;
-    return RelocToApply();
+    return 0;
   }
 
-  RelocToApply visitMachO(uint32_t RelocType, RelocationRef R, uint64_t Value) {
+  uint64_t visitMachO(uint32_t RelocType, RelocationRef R, uint64_t Value) {
     switch (ObjToVisit.getArch()) {
     default: break;
     case Triple::x86_64:
@@ -277,7 +265,7 @@ private:
       }
     }
     HasError = true;
-    return RelocToApply();
+    return 0;
   }
 
   int64_t getELFAddend(RelocationRef R) {
@@ -287,108 +275,88 @@ private:
     return *AddendOrErr;
   }
 
-  uint8_t getLengthMachO64(RelocationRef R) {
-    const MachOObjectFile *Obj = cast<MachOObjectFile>(R.getObject());
-    return Obj->getRelocationLength(R.getRawDataRefImpl());
-  }
-
   /// Operations
 
   /// 386-ELF
-  RelocToApply visitELF_386_NONE(RelocationRef R) {
-    return RelocToApply(0, 0);
+  uint64_t visitELF_386_NONE(RelocationRef R) {
+    return 0;
   }
 
   // Ideally the Addend here will be the addend in the data for
   // the relocation. It's not actually the case for Rel relocations.
-  RelocToApply visitELF_386_32(RelocationRef R, uint64_t Value) {
-    return RelocToApply(Value, 4);
+  uint64_t visitELF_386_32(RelocationRef R, uint64_t Value) {
+    return Value;
   }
 
-  RelocToApply visitELF_386_PC32(RelocationRef R, uint64_t Value) {
-    uint64_t Address = R.getOffset();
-    return RelocToApply(Value - Address, 4);
+  uint64_t visitELF_386_PC32(RelocationRef R, uint64_t Value) {
+    return Value - R.getOffset();
   }
 
   /// X86-64 ELF
-  RelocToApply visitELF_X86_64_NONE(RelocationRef R) {
-    return RelocToApply(0, 0);
+  uint64_t visitELF_X86_64_NONE(RelocationRef R) {
+    return 0;
   }
-  RelocToApply visitELF_X86_64_64(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    return RelocToApply(Value + Addend, 8);
+
+  uint64_t visitELF_X86_64_64(RelocationRef R, uint64_t Value) {
+    return Value + getELFAddend(R);
   }
-  RelocToApply visitELF_X86_64_PC32(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    uint64_t Address = R.getOffset();
-    return RelocToApply(Value + Addend - Address, 4);
+
+  uint64_t visitELF_X86_64_PC32(RelocationRef R, uint64_t Value) {
+    return Value + getELFAddend(R) - R.getOffset();
   }
-  RelocToApply visitELF_X86_64_32(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    uint32_t Res = (Value + Addend) & 0xFFFFFFFF;
-    return RelocToApply(Res, 4);
+
+  uint64_t visitELF_X86_64_32(RelocationRef R, uint64_t Value) {
+    return (Value + getELFAddend(R)) & 0xFFFFFFFF;
   }
-  RelocToApply visitELF_X86_64_32S(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    int32_t Res = (Value + Addend) & 0xFFFFFFFF;
-    return RelocToApply(Res, 4);
+
+  uint64_t visitELF_X86_64_32S(RelocationRef R, uint64_t Value) {
+    return (Value + getELFAddend(R)) & 0xFFFFFFFF;
   }
 
   /// BPF ELF
-  RelocToApply visitELF_BPF_64_32(RelocationRef R, uint64_t Value) {
-    uint32_t Res = Value & 0xFFFFFFFF;
-    return RelocToApply(Res, 4);
+  uint64_t visitELF_BPF_64_32(RelocationRef R, uint64_t Value) {
+    return Value & 0xFFFFFFFF;
   }
-  RelocToApply visitELF_BPF_64_64(RelocationRef R, uint64_t Value) {
-    return RelocToApply(Value, 8);
+
+  uint64_t visitELF_BPF_64_64(RelocationRef R, uint64_t Value) {
+    return Value;
   }
 
   /// PPC64 ELF
-  RelocToApply visitELF_PPC64_ADDR32(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    uint32_t Res = (Value + Addend) & 0xFFFFFFFF;
-    return RelocToApply(Res, 4);
+  uint64_t visitELF_PPC64_ADDR32(RelocationRef R, uint64_t Value) {
+    return (Value + getELFAddend(R)) & 0xFFFFFFFF;
   }
-  RelocToApply visitELF_PPC64_ADDR64(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    return RelocToApply(Value + Addend, 8);
+
+  uint64_t visitELF_PPC64_ADDR64(RelocationRef R, uint64_t Value) {
+    return Value + getELFAddend(R);
   }
 
   /// PPC32 ELF
-  RelocToApply visitELF_PPC_ADDR32(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    uint32_t Res = (Value + Addend) & 0xFFFFFFFF;
-    return RelocToApply(Res, 4);
+  uint64_t visitELF_PPC_ADDR32(RelocationRef R, uint64_t Value) {
+    return (Value + getELFAddend(R)) & 0xFFFFFFFF;
   }
 
   /// Lanai ELF
-  RelocToApply visitELF_Lanai_32(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    uint32_t Res = (Value + Addend) & 0xFFFFFFFF;
-    return RelocToApply(Res, 4);
+  uint64_t visitELF_Lanai_32(RelocationRef R, uint64_t Value) {
+    return (Value + getELFAddend(R)) & 0xFFFFFFFF;
   }
 
   /// MIPS ELF
-  RelocToApply visitELF_MIPS_32(RelocationRef R, uint64_t Value) {
-    uint32_t Res = Value & 0xFFFFFFFF;
-    return RelocToApply(Res, 4);
+  uint64_t visitELF_MIPS_32(RelocationRef R, uint64_t Value) {
+    return Value & 0xFFFFFFFF;
   }
 
   /// MIPS64 ELF
-  RelocToApply visitELF_MIPS64_32(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    uint32_t Res = (Value + Addend) & 0xFFFFFFFF;
-    return RelocToApply(Res, 4);
+  uint64_t visitELF_MIPS64_32(RelocationRef R, uint64_t Value) {
+    return (Value + getELFAddend(R)) & 0xFFFFFFFF;
   }
 
-  RelocToApply visitELF_MIPS64_64(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    uint64_t Res = (Value + Addend);
-    return RelocToApply(Res, 8);
+  uint64_t visitELF_MIPS64_64(RelocationRef R, uint64_t Value) {
+    return Value + getELFAddend(R);
   }
 
   // AArch64 ELF
-  RelocToApply visitELF_AARCH64_ABS32(RelocationRef R, uint64_t Value) {
+  uint64_t visitELF_AARCH64_ABS32(RelocationRef R, uint64_t Value) {
     int64_t Addend = getELFAddend(R);
     int64_t Res =  Value + Addend;
 
@@ -396,16 +364,15 @@ private:
     if (Res < INT32_MIN || Res > UINT32_MAX)
       HasError = true;
 
-    return RelocToApply(static_cast<uint32_t>(Res), 4);
+    return static_cast<uint32_t>(Res);
   }
 
-  RelocToApply visitELF_AARCH64_ABS64(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    return RelocToApply(Value + Addend, 8);
+  uint64_t visitELF_AARCH64_ABS64(RelocationRef R, uint64_t Value) {
+    return Value + getELFAddend(R);
   }
 
   // SystemZ ELF
-  RelocToApply visitELF_390_32(RelocationRef R, uint64_t Value) {
+  uint64_t visitELF_390_32(RelocationRef R, uint64_t Value) {
     int64_t Addend = getELFAddend(R);
     int64_t Res = Value + Addend;
 
@@ -413,77 +380,71 @@ private:
     if (Res < INT32_MIN || Res > UINT32_MAX)
       HasError = true;
 
-    return RelocToApply(static_cast<uint32_t>(Res), 4);
+    return static_cast<uint32_t>(Res);
   }
 
-  RelocToApply visitELF_390_64(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    return RelocToApply(Value + Addend, 8);
+  uint64_t visitELF_390_64(RelocationRef R, uint64_t Value) {
+    return Value + getELFAddend(R);
   }
 
-  RelocToApply visitELF_SPARC_32(RelocationRef R, uint32_t Value) {
-    int32_t Addend = getELFAddend(R);
-    return RelocToApply(Value + Addend, 4);
+  uint64_t visitELF_SPARC_32(RelocationRef R, uint32_t Value) {
+    return Value + getELFAddend(R);
   }
 
-  RelocToApply visitELF_SPARCV9_32(RelocationRef R, uint64_t Value) {
-    int32_t Addend = getELFAddend(R);
-    return RelocToApply(Value + Addend, 4);
+  uint64_t visitELF_SPARCV9_32(RelocationRef R, uint64_t Value) {
+    return Value + getELFAddend(R);
   }
 
-  RelocToApply visitELF_SPARCV9_64(RelocationRef R, uint64_t Value) {
-    int64_t Addend = getELFAddend(R);
-    return RelocToApply(Value + Addend, 8);
+  uint64_t visitELF_SPARCV9_64(RelocationRef R, uint64_t Value) {
+    return Value + getELFAddend(R);
   }
 
-  RelocToApply visitELF_ARM_ABS32(RelocationRef R, uint64_t Value) {
+  uint64_t visitELF_ARM_ABS32(RelocationRef R, uint64_t Value) {
     int64_t Res = Value;
 
     // Overflow check allows for both signed and unsigned interpretation.
     if (Res < INT32_MIN || Res > UINT32_MAX)
       HasError = true;
 
-    return RelocToApply(static_cast<uint32_t>(Res), 4);
+    return static_cast<uint32_t>(Res);
   }
 
-  RelocToApply visitELF_HEX_32(RelocationRef R, uint64_t Value) {
+  uint64_t visitELF_HEX_32(RelocationRef R, uint64_t Value) {
     int64_t Addend = getELFAddend(R);
-    return RelocToApply(Value + Addend, 4);
+    return Value + Addend;
   }
 
-  RelocToApply visitELF_AMDGPU_ABS32(RelocationRef R, uint64_t Value) {
+  uint64_t visitELF_AMDGPU_ABS32(RelocationRef R, uint64_t Value) {
     int64_t Addend = getELFAddend(R);
-    return RelocToApply(Value + Addend, 4);
+    return Value + Addend;
   }
 
-  RelocToApply visitELF_AMDGPU_ABS64(RelocationRef R, uint64_t Value) {
+  uint64_t visitELF_AMDGPU_ABS64(RelocationRef R, uint64_t Value) {
     int64_t Addend = getELFAddend(R);
-    return RelocToApply(Value + Addend, 8);
+    return Value + Addend;
   }
 
   /// I386 COFF
-  RelocToApply visitCOFF_I386_SECREL(RelocationRef R, uint64_t Value) {
-    return RelocToApply(static_cast<uint32_t>(Value), /*Width=*/4);
+  uint64_t visitCOFF_I386_SECREL(RelocationRef R, uint64_t Value) {
+    return static_cast<uint32_t>(Value);
   }
 
-  RelocToApply visitCOFF_I386_DIR32(RelocationRef R, uint64_t Value) {
-    return RelocToApply(static_cast<uint32_t>(Value), /*Width=*/4);
+  uint64_t visitCOFF_I386_DIR32(RelocationRef R, uint64_t Value) {
+    return static_cast<uint32_t>(Value);
   }
 
   /// AMD64 COFF
-  RelocToApply visitCOFF_AMD64_SECREL(RelocationRef R, uint64_t Value) {
-    return RelocToApply(static_cast<uint32_t>(Value), /*Width=*/4);
+  uint64_t visitCOFF_AMD64_SECREL(RelocationRef R, uint64_t Value) {
+    return static_cast<uint32_t>(Value);
   }
 
-  RelocToApply visitCOFF_AMD64_ADDR64(RelocationRef R, uint64_t Value) {
-    return RelocToApply(Value, /*Width=*/8);
+  uint64_t visitCOFF_AMD64_ADDR64(RelocationRef R, uint64_t Value) {
+    return Value;
   }
 
   // X86_64 MachO
-  RelocToApply visitMACHO_X86_64_UNSIGNED(RelocationRef R, uint64_t Value) {
-    uint8_t Length = getLengthMachO64(R);
-    Length = 1<<Length;
-    return RelocToApply(Value, Length);
+  uint64_t visitMACHO_X86_64_UNSIGNED(RelocationRef R, uint64_t Value) {
+    return Value;
   }
 };
 
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
index 3dc1ec5..7365c92 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -1104,14 +1104,14 @@ DWARFContextInMemory::DWARFContextInMemory(const object::ObjectFile &Obj,
       }
 
       object::RelocVisitor V(Obj);
-      object::RelocToApply R(V.visit(Reloc.getType(), Reloc, *SymAddrOrErr));
+      uint64_t Val = V.visit(Reloc.getType(), Reloc, *SymAddrOrErr);
       if (V.error()) {
         SmallString<32> Name;
         Reloc.getTypeName(Name);
         errs() << "error: failed to compute relocation: " << Name << "\n";
         continue;
       }
-      Map->insert({Reloc.getOffset(), {R.Value}});
+      Map->insert({Reloc.getOffset(), {Val}});
     }
   }
 }
-- 
2.7.4