Kylix Compiler and RTL

Overview

• Command-line tools - what’s new
• DCC is a native Linux executable
• All-new portable code inline assembler
• Supports MMX, Pentium pro, SIMD, 10 byte data structure
• DCC makes native executables (ELF format, x86)
• Can use .O files with restrictions (no C++)
• Command-line tools - what’s out
• TASM and tools
• Borland make (use GNU make)
• brcc (resource script compiler)
• We’ll provide a way to get binary data and strings into executables

Kylix Compiler and RTL

• Command-line tools – what’s different
• Only '-' for command-line switches
• Colon ':' instead of semicolon ';' for path separator
• ‘;’ Is a valid character for Linux file names
• Resources
• Restrictions on windows resource "rip and replace”
• Resource section is a reserved size, you can replace data
• Can’t change the name or add a resource name
• No introspection (enumeration and discovery) like in windows
• We’ll use ELF format extensions – spec allows new segments
• No resource types
• Editing will not be straightforward
• Position independent code (PIC)
• Linux loader - all code is relocatable (uses EBX)
• Shared objects must use PIC

Kylix Compiler and RTL

• Language syntax - what’s new
• Expression evaluation in conditional defines
• {$IF defined(SomeSymbol) and (SomeConstant < 11.0)}
• And, or, XOR, …
• Libraries / packages compile to shared object (.So)
• DCU for executables
• DPU for PIC code - shared objects
• Unit, program, library keywords
• Case sensitive file name - must match name after keyword
• Conditional LINUX symbol is defined
• Assembler – VMToffset, DMToffset
• Mov eax, VMToffset(TMyObject virtual method)
• Moves the offset # - VMT tables may move around

Kylix Compiler and RTL

• Language syntax - what’s out
• Variables on absolute addresses
• var X: integer absolute $1234;
• You can do absolute variables on another variable
• Conditional symbol WIN32 is not defined
• IFDEF style
• Use $IFDEF WIN32 and $IFDEF LINUX
• Don’t use $ELSE

Kylix Compiler and RTL

• Language syntax
• What's different (still under consideration)
• stdcall mapped to cdecl
• No impact on Pascal code
• Assembler code must clean up calls to cdecl functions
• safecall mapped to cdecl
• Primarily used on windows to handle exceptions
• Turns exceptions into a function result
• Still of some use in RPC calls – use proxies and stubs
• Will affect Pascal code – we’ll try to issue a warning
• Both will have an impact on assembler code

Kylix Compiler and RTL

• Run time library
• What's new
• Portable variants – not the Windows variant
• Includes support for variant arrays and safe arrays
• Support for registering custom variant data types
• Data coercion, data copying, operator operations, method invocation
• Test case already implemented – complex numbers
• WideStrings are reference counted
• What's out
• Units such as ComObj, ComServ, ActiveX, windows
• Safecall exceptions
• Raiselastwin32err, OleCheck, win32check
• ExpandUNCFileName (\\server\filename)
• Drive letter functions – extractfiledrive()

Kylix Compiler and RTL

• Run time library - what’s different
• WideChar is still 2 bytes (Linux wchar_t is 4 bytes)
• Linux system calls don’t use WideChars – they use UTF-8
• AnsiStrings encoded as UTF-8
• On Windows AnsiStrings are multi-byte defined by the locale
• ResourceStrings as UTF-8 in exe file
• IInterface replaces IUnknown as base type
• Use IUnknown for windows interfaces
• Use IInterface for application interfaces
• TResourceStream – pulls from ELF executable
• Component streaming depends on component differences
• TThreads
• OS dependent
• Linux distribution differences

Kylix Compiler and RTL

• Run time library - what’s different
• File system
• Filename case sensitivity
• Uses clause, your code, RTL calls
• File name extensions (.Pas, .dpr, .dfm, .dcu, …)
• Classes, SysUtils, …
• File times in Unix format is different
• Windows packed data 1980
• Linux # of seconds since 1970
• No drive letters (DiskFree, DiskSize, ExtractFileDrive)
• Path name separator is '/' not '\'
• New PathSeparator constant, IsPathDelimiter, IncludeTrailingBackslash, ExtractFilePath, etc will work

Demos

• Text book example
• X Windows example
• Simple CLX
• Questions and (Hopefully) Answers
• Introduction to CLX