[WebAssembly] Allow for signed relocation addends

[sbc100]

Summary

Addends are used as offsets to addresses of globals
and can be both positive and negative. This change
brings libObject in line with the spec and the MC
layer.

[sbc100]

• revert debugging

include/llvm/ObjectYAML/WasmYAML.h

struct Function {
   std::vector<LocalDecl> Locals;
   yaml::BinaryRef Body;
 };
 
 struct Relocation {
   RelocType Type;
   uint32_t Index;
   yaml::Hex32 Offset;
-  yaml::Hex32 Addend;
+  int32_t Addend;
 };
 
 struct DataSegment {
   uint32_t Index;
   wasm::WasmInitExpr Offset;
   yaml::BinaryRef Content;
 };
 

lib/Object/WasmObjectFile.cpp

while (RelocCount--) {
     memset(&Reloc, 0, sizeof(Reloc));
     Reloc.Type = readVaruint32(Ptr);
     Reloc.Offset = readVaruint32(Ptr);
     Reloc.Index = readVaruint32(Ptr);
     switch (Reloc.Type) {
     case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
     case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
     case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
+    case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
       break;
     case wasm::R_WEBASSEMBLY_GLOBAL_ADDR_LEB:
     case wasm::R_WEBASSEMBLY_GLOBAL_ADDR_SLEB:
     case wasm::R_WEBASSEMBLY_GLOBAL_ADDR_I32:
-      Reloc.Addend = readVaruint32(Ptr);
+      Reloc.Addend = readVarint32(Ptr);
       break;
     default:
       return make_error<GenericBinaryError>("Bad relocation type",
                                             object_error::parse_failed);
     }
     Section->Relocations.push_back(Reloc);
   }
   if (Ptr != End)

lib/ObjectYAML/WasmYAML.cpp

void MappingTraits<WasmYAML::Function>::mapping(IO &IO,
   IO.mapRequired("Body", Function.Body);
 }
 
 void MappingTraits<WasmYAML::Relocation>::mapping(
     IO &IO, WasmYAML::Relocation &Relocation) {
   IO.mapRequired("Type", Relocation.Type);
   IO.mapRequired("Index", Relocation.Index);
   IO.mapRequired("Offset", Relocation.Offset);
-  IO.mapRequired("Addend", Relocation.Addend);
+  IO.mapOptional("Addend", Relocation.Addend, 0);
 }
 
 void MappingTraits<WasmYAML::LocalDecl>::mapping(
     IO &IO, WasmYAML::LocalDecl &LocalDecl) {
   IO.mapRequired("Type", LocalDecl.Type);
   IO.mapRequired("Count", LocalDecl.Count);
 }
 

test/ObjectYAML/wasm/code_section.yaml

- Type:            FUNCTION
     FunctionTypes:
       - 0
       - 1
   - Type:            CODE
     Relocations:
       - Type:            R_WEBASSEMBLY_TABLE_INDEX_SLEB
         Index:           0
         Offset:          0x00000006
-        Addend:          0x00000000
       - Type:            R_WEBASSEMBLY_FUNCTION_INDEX_LEB
         Index:           1
         Offset:          0x00000025
-        Addend:          0x00000000
     Functions:
       - Locals:
          - Type:            I32
            Count:           3
         Body:            418080808000210020002101200111808080800000210220020F0B
       - Locals:
          - Type:            I32
            Count:           1

 # CHECK:        ParamTypes:
 # CHECK:          - I32
 # CHECK:          - I64
 # CHECK:  - Type:            CODE
 # CHECK:    Relocations:
 # CHECK:      - Type:            R_WEBASSEMBLY_TABLE_INDEX_SLEB
 # CHECK:        Index:           0
 # CHECK:        Offset:          0x00000006
-# CHECK:        Addend:          0x00000000
 # CHECK:      - Type:            R_WEBASSEMBLY_FUNCTION_INDEX_LEB
 # CHECK:        Index:           1
 # CHECK:        Offset:          0x00000025
-# CHECK:        Addend:          0x00000000
 # CHECK:    Functions:
 # CHECK:      - Locals:
 # CHECK:         - Type:            I32
 # CHECK:           Count:           3
 # CHECK:        Body:            418080808000210020002101200111808080800000210220020F0B
 # CHECK:      - Locals:
 # CHECK:         - Type:            I32
 # CHECK:           Count:           1
 # CHECK:        Body:            108180808000210020000F0B

test/ObjectYAML/wasm/data_section.yaml

 # RUN: yaml2obj %s | obj2yaml | FileCheck %s
 --- !WASM
 FileHeader:
   Version:         0x00000001
 Sections:
   - Type:            MEMORY
     Memories:
       - Initial:         0x00000003
   - Type:            DATA
     Segments:
       - Index:           0
         Offset:
           Opcode:          I32_CONST
           Value:           4
         Content:         '10001000'
+    Relocations:
+      - Type:            R_WEBASSEMBLY_GLOBAL_ADDR_I32
+        Index:           0
+        Offset:          0x00000006
+        Addend:          8
+      - Type:            R_WEBASSEMBLY_GLOBAL_ADDR_I32
+        Index:           0
+        Offset:          0x00000006
+        Addend:          -6
 ...
 # CHECK: --- !WASM
 # CHECK: FileHeader:
 # CHECK:   Version:           0x00000001
 # CHECK: Sections:
 # CHECK:   - Type:            DATA
-# CHECK:     Segments:
-# CHECK:       - Index:           0
-# CHECK:         Offset:
-# CHECK:           Opcode:          I32_CONST
-# CHECK:           Value:           4
-# CHECK:         Content:         '10001000'
-# CHECK: ...
+# CHECK-NEXT:     Relocations:
+# CHECK-NEXT:      - Type:            R_WEBASSEMBLY_GLOBAL_ADDR_I32
+# CHECK-NEXT:        Index:           0
+# CHECK-NEXT:        Offset:          0x00000006
+# CHECK-NEXT:        Addend:          8
+# CHECK-NEXT:      - Type:            R_WEBASSEMBLY_GLOBAL_ADDR_I32
+# CHECK-NEXT:        Index:           0
+# CHECK-NEXT:        Offset:          0x00000006
+# CHECK-NEXT:        Addend:          -6
+# CHECK-NEXT:     Segments:
+# CHECK-NEXT:       - Index:           0
+# CHECK-NEXT:         Offset:
+# CHECK-NEXT:           Opcode:          I32_CONST
+# CHECK-NEXT:           Value:           4
+# CHECK-NEXT:         Content:         '10001000'
+# CHECK-NEXT: ...