[Object][WebAssembly] Fix data segment offsets higher than 2^31

Fixes: #58555

Author: sbc100

llvm/include/llvm/BinaryFormat/Wasm.h

@@ -333,8 +333,8 @@ struct WasmTable {
 struct WasmInitExprMVP {
   uint8_t Opcode;
   union {
-    int32_t Int32;
-    int64_t Int64;
+    uint32_t Int32;
+    uint64_t Int64;
     uint32_t Float32;
     uint64_t Float64;
     uint32_t Global;

llvm/lib/Object/WasmObjectFile.cpp

@@ -201,10 +201,10 @@ static Error readInitExpr(wasm::WasmInitExpr &Expr,
   Expr.Inst.Opcode = readOpcode(Ctx);
   switch (Expr.Inst.Opcode) {
   case wasm::WASM_OPCODE_I32_CONST:
-    Expr.Inst.Value.Int32 = readVarint32(Ctx);
+    Expr.Inst.Value.Int32 = readVaruint32(Ctx);
     break;
   case wasm::WASM_OPCODE_I64_CONST:
-    Expr.Inst.Value.Int64 = readVarint64(Ctx);
+    Expr.Inst.Value.Int64 = readVaruint64(Ctx);
     break;
   case wasm::WASM_OPCODE_F32_CONST:
     Expr.Inst.Value.Float32 = readFloat32(Ctx);

llvm/test/Object/Wasm/data-offsets.yaml

@@ -0,0 +1,16 @@
+# RUN: yaml2obj %s | llvm-objdump -s -
+
+## Tests data offsets above 2**31
+
+--- !WASM
+FileHeader:
+  Version:         0x00000001
+Sections:
+  - Type:            DATA
+    Segments:
+      - SectionOffset:   0
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           2147483649
+        Content:         '6401020304'

llvm/test/ObjectYAML/wasm/global_section.yaml

@@ -10,7 +10,7 @@ Sections:
         Mutable:     false
         InitExpr:
           Opcode:          I64_CONST
-          Value:           -5
+          Value:           5
 ...
 # CHECK: --- !WASM
 # CHECK: FileHeader:
@@ -23,5 +23,5 @@ Sections:
 # CHECK:        Mutable:     false
 # CHECK:        InitExpr:
 # CHECK:          Opcode:          I64_CONST
-# CHECK:          Value:           -5
+# CHECK:          Value:           5
 # CHECK: ...