FieldValueSizeDecoder: Use pointer size defined in decompiled module.

Use same prefixes for PE sections as ildasm.

ICSharpCode.Decompiler/Disassembler/ReflectionDisassembler.cs

@@ -1111,8 +1111,11 @@ namespace ICSharpCode.Decompiler.Disassembler
 			output.Write(' ');
 			var fieldName = metadata.GetString(fieldDefinition.Name);
 			output.Write(DisassemblerHelpers.Escape(fieldName));
+			char sectionPrefix = 'D';
 			if (fieldDefinition.HasFlag(FieldAttributes.HasFieldRVA)) {
-				output.Write(" at D_{0:X8}", fieldDefinition.GetRelativeVirtualAddress());
+				int rva = fieldDefinition.GetRelativeVirtualAddress();
+				sectionPrefix = GetRVASectionPrefix(module.Reader.PEHeaders, rva);
+				output.Write(" at {1}_{0:X8}", rva, sectionPrefix);
 			}
 
 			var defaultValue = fieldDefinition.GetDefaultValue();
@@ -1139,7 +1142,7 @@ namespace ICSharpCode.Decompiler.Disassembler
 						initVal = fieldDefinition.GetInitialValue(module.Reader, null);
 					} catch (BadImageFormatException ex) {
 						initVal = default;
-						output.WriteLine("// .data D_{0:X8} = {1}", fieldDefinition.GetRelativeVirtualAddress(), ex.Message);
+						output.WriteLine("// .data {2}_{0:X8} = {1}", fieldDefinition.GetRelativeVirtualAddress(), ex.Message, sectionPrefix);
 					}
 					if (initVal.Length > 0) {
 						var sectionHeader = module.Reader.PEHeaders.SectionHeaders[sectionIndex];
@@ -1151,13 +1154,29 @@ namespace ICSharpCode.Decompiler.Disassembler
 						} else if (sectionHeader.Name != ".data") {
 							output.Write($"/* {sectionHeader.Name} */ ");
 						}
-						output.Write($"D_{rva:X8} = bytearray ");
+						output.Write($"{sectionPrefix}_{rva:X8} = bytearray ");
 						WriteBlob(initVal);
 						output.WriteLine();
 					}
 				}
 			}
 		}
+
+		char GetRVASectionPrefix(System.Reflection.PortableExecutable.PEHeaders headers, int rva)
+		{
+			int sectionIndex = headers.GetContainingSectionIndex(rva);
+			if (sectionIndex < 0)
+				return 'D';
+			var sectionHeader = headers.SectionHeaders[sectionIndex];
+			switch (sectionHeader.Name) {
+				case ".tls":
+					return 'T';
+				case ".text":
+					return 'I';
+				default:
+					return 'D';
+			}
+		}
 		#endregion
 
 		#region Disassemble Property

ICSharpCode.Decompiler/SRMExtensions.cs

@@ -387,12 +387,15 @@ namespace ICSharpCode.Decompiler
 		sealed class FieldValueSizeDecoder : ISignatureTypeProvider<int, GenericContext>
 		{
 			readonly MetadataModule module;
-			// This is the same as Cecil does, but probably not a good idea.
-			static readonly int pointerSize = IntPtr.Size;
+			readonly int pointerSize;
 
 			public FieldValueSizeDecoder(ICompilation typeSystem = null)
 			{
 				this.module = (MetadataModule)typeSystem?.MainModule;
+				if (module == null)
+					this.pointerSize = IntPtr.Size;
+				else
+					this.pointerSize = module.PEFile.Reader.PEHeaders.PEHeader.Magic == PEMagic.PE32 ? 4 : 8;
 			}
 
 			public int GetArrayType(int elementType, ArrayShape shape) => GetPrimitiveType(PrimitiveTypeCode.Object);