Debugger Callstack Resolver is a Delphi IDE plugin that I wrote in 2011 to make the IDE’s CPU View more readable. It colors different instructions, resolves absolute and memory address jump and call targets and shows their function name if available. It also uses the *.jdbg to show more information (the dcc32 compiler’s jdbg files are for the debug build of the compiler and haven’t match the deployed version since jdbg files exist)

This plugin supports Delphi 2009 – 10.1 Berlin.

[Download]

Due to many requests, I took the time to update my tools (IDE Fix Pack, DDevExtensions, DFMCheck) for the newest Delphi version. Delphi 10.2 RTM will be the last version that all my tools support. I won’t be able to recompiled them for any 10.2 Update because my update subscription has expired and I didn’t (intentionally) renew it. Coincidentally I didn’t get a renewal message this time either.

This doesn’t mean that I won’t release newer versions of my tools, but I can’t support newer Delphi versions or 10.2 updates if the tools need to be recompiled. When I find some new possible optimizations or fixes for annoying bugs and time to work on them, Delphi 2009-10.2 RTM users will be able to use them.

Changelog:

• Fixed: Disable DynArraySetLength patch if 10.1 Berlin Update 2 is detected.
• Fixed: “clang template debug symbol bloat” disabled for 10 Seattle and newer.
• Added: IDE minimize doesn’t shrink main window to width and height zero.
• Added: RAD Studio 10.2 support

Download:

Download (fastdcc):

There is also a new IDE Fix Pack 6.0 Beta 4 that contains all the above and the experimental 64 bit compiler performance optimizations.

Download:

This RAD Studio IDE plugin enables the F12 debug hotkey for the Win32 debugger for Windows Vista, 7, 8, 8.1 and Windows 10.

If you don’t know what this plugin is for, then you don’t need it.

Download

Eugene Kotlyarov found a problem with Castalia’s clipboard history feature combined with a TRichEdit in a debugged application. If you copy text from the RichEdit to the clipboard the first time, the IDE and the debugged application stop responding and start reacting after a ~30 seconds timeout. After that, copy to clipboard works until you restart the debugged application. Win32 and Win64 have the same problem.
https://plus.google.com/+EugeneKotlyarovPlus/posts/R783AB3DfYL

What happens:

• The debugged application invokes WM_COPY by Ctrl+C/Ctrl+Insert/Context-menu “Copy”.
• WM_COPY set the RichEdit as clipboard renderer without putting the actual data into the clipboard.
• Castalia’s TClipboardHistoryForm receives the WM_CLIPBOARDUPDATE message in the main thread and calls GetClipboardData (via Clipboard.AsText).
• The debugged application’s RichEdit loads a DLL to provide the actual clipboard data for the GetClipboardData call.
• The debugger receives a LOAD_DLL_DEBUG_EVENT for the DLL.
• The debugger posts a message to the debugger window in the main thread and goes to sleep with WaitForSingleObject to wait for the debugger window to process the DLL load event.

Now everything waits. GetClipboardData is blocked because the clipboard owner, the debugged application, is trapped in a debugger event. The debugger is blocked because the debugger window doesn’t get the posted message because the blocked GetClipboardData prevents the main thread from processing messages.

Fortunately a Microsoft developer knew about this possible deadlock and put a timeout into GetClipboardData.

A solution that I’ve put into the IDE Fix Pack development version (not available) moves the WM_CLIPBOARDUPDATE message handling into a thread window, so that the call to GetClipboardData doesn’t block the main thread and the debugger can process the DLL load event.

Calling a virtual method through an interface always was a lot slower than calling a static method through an interface. But why is that? Sure, the virtual method call costs some time, but comparing it with the difference of a normal static and virtual method call shows that the timings diverge too much.

Let’s assume we have this declaration:

type
  IMyInterface = interface
    procedure Test(A, B: Integer);
  end;
  TTest = class(TInterfacedObject, IMyInterface)
  public
    procedure Test(A, B: Integer); virtual;
  end;

The compiler will generate a helper function for the interface method “Test”. This helper converts the “MyIntf” interface reference in the call “MyIntf.Test()” to the object reference behind the interface and then jumps to the virtual method.

add eax,-$0C   // convert the interface reference to the object reference
push eax       // save the object reference on the stack
mov eax,[eax]  // access the VMT
mov eax,[eax]  // get the “Test” VMT method address
xchg [esp],eax // swap the object ref on the stack with the method address
ret            // do the jump to the method address

This is very slow as you can see in the table above. If you know the “XCHG mem,reg” instruction, then you also know that it has an implicit “CPU LOCK” that slows down the method call a lot. But why is it using the XCHG instruction in the first place? Well, we are in between a method call. All the parameters are already loaded in to EAX, EDX and ECX. So we can’t use those to do the swap. The only way is to use the stack as temporary variable, and XCHG seemed to be the choice of the compiler engineer at the time interfaces were introduced to Delphi.

Let’s change that code to not use XCHG.

add eax,-$0 C      // convert the interface reference to the object reference
push eax           // reserve space for the method address used by RET
push eax           // save the object reference on the stack
mov eax,[eax]      // access the VMT
mov eax,[eax]      // get the “Test” VMT method address
mov [esp+04],eax   // write the method address to the reserved space
pop eax            // restore the object reference
ret                // do the jump to the method address

This is a lot faster, but still slow compared to the “Instance call”. The helper has a lot of memory accesses, but they shouldn’t slow it that much down, especially not in a tight loop when everything comes from the CPU’s cache.

So where does the code spend the time? Well, modern CPUs (after P1) have a feature called “return stack buffer”. The CPU puts the return address on the “return stack buffer” for every CALL instruction so it can predict where the RET instruction will jump to. This requires that every CALL is matched by a RET. But wait, the helper uses a RET for an indirect jump. We have the CALL from the interface method call, the RET in the helper and the RET in the actual method. That doesn’t match up. In other words, this helper renders the “return stack buffer” invalid what comes with a performance hit because the CPU can’t predict where to jump.

Let’s see what happens if we replace the RET with a JMP.

add eax,-$0C        // convert the interface reference to the object reference
push eax            // save the object reference on the stack
mov eax,[eax]       // access the VMT
push DWORD PTR [eax]// save the “Test” VMT entry method address on the stack
add esp,$04         // skip the method address stack entry
pop eax             // restore the object reference
jmp [esp-$08]       // jump to the method address

UPDATE: As fast as this implementation may be, it has a problem. As Allen and Mark pointed out, it accesses memory on the stack that is treated as free memory from the system. So if a hardware interrupt is triggered between the “add esp,$04” and the “jmp [esp-$08]”, the data on the stack is overwritten and the jump will end somewhere but not where it should be.

UPDATE 2: Thorsten Engler sent me an e-mail that invalidates the “hardware interrupt problem”. All interrupts are handled in kernel mode and kernel mode code doesn’t touch the user stack. The CPU itself switches the SS:ESP before invoking the interrupt handler.

Based on AMD64 Architecture Programmer’s Manual Volume 2 – System Programming Rev.3.22 Section 8.7.3 Interrupt To Higher Privilege:

When a control transfer to an exception or interrupt handler running at a higher privilege occurs (numerically lower CPL value), the processor performs a stack switch using the following steps:

1. The target CPL is read by the processor from the target code-segment DPL and used as an index into the TSS for selecting the new stack pointer (SS:ESP). For example, if the target CPL is 1, the processor selects the SS:ESP for privilege-level 1 from the TSS.
2. Pushes the return stack pointer (old SS:ESP) onto the new stack. The SS value is padded with two bytes to form a doubleword.

Delphi 10.1 Berlin reintroduces UTF8String and RawByteString for the NextGen compilers (Android, iOS). But ShortString and AnsiString are still missing. The compiler has full support for them but you can’t use them because they are declared with a leading underscore in the System.pas unit what makes them inaccessible because “_” is compiled to “@” what you can’t use for an identifier.

By patching DCU files it is possible to make those hidden types accessible.

The unit System.ByteStrings for 10.1 Berlin reintroduces

• ShortString
• AnsiString
• AnsiChar
• PAnsiChar
• PPAnsiChar
• UTF8String (XE5-10 Seattle)
• PUTF8String (XE5-10 Seattle)
• RawByteString (XE5-10 Seattle)
• PRawByteString (XE5-10 Seattle)

Usage:
Add the System.ByteStrings.dcu’s path to the compiler’s search path and add the unit to your uses clauses.

There is no *.PAS file because the DCU is patched with a hex editor to get access to the hidden types.

IDE Fix Pack 5.95 supports RAD Studio 10.1 Berlin.

When Windows Defender (or any other anti-virus tool) sees the compiler creating a DCU file and the compiler calls CloseHandle on the file handle, the virus/malware scanner blocks the thread and takes its time to have a look at the file. This causes CloseHandle to take more than 2 milliseconds per file on my system. If you have 2500 units this sums up to 5 seconds. With Windows Defender disabled those 5 seconds go back to under 100 milliseconds.
Because the compiler can’t work in those 5 seconds, the IDE Fix Pack now delegates the CloseHandle calls to a background thread. This means Windows Defender can scan the file while the compiler works on the next units without being blocked by the scan.
On my Win32 test project this parallel execution made the rebuild 5 seconds faster. IDE Fix Pack guarantees that all written DCU files are closed before the binary executable is created. So if you have only some units you won’t see much of a speed improvement because the main thread may wait for the background thread to close all remaining files.

Changelog:

• Added: RAD Studio 10.1 Berlin support
• Added: CloseHandle for created DCU files is delegated to a background thread. Windows Defender “workaround”
• Added: Fix for RSP-14557: DynArraySetLength – resizing an array of managed type is causing entire copy instead of realloc (D10.1, only the IDE)
• Added: Fix for RSP-13116: TCustomImageList.BeginUpdate/EndUpdate (D10.0)

Download:

Download (fastdcc):

There is also a new IDE Fix Pack 6.0 Beta 3 that contains all the above and the experimental 64 bit compiler performance optimizations.

Download:

The DDevExtensions and the DFMCheck IDE plugins are now available for 10.1 Berlin.

Download:

DDevExtensions Changelog:

• Version 2.84 (2016-05-28)
  • Added: TAB key works like ENTER in the CodeInsight window.
  • Added: 10.1 Berlin support

I made a small update for DFMCheck RAD Studio IDE plugin. The new version 1.6 adds a “Yes to all” button to the “Open/Close all forms” confirmation dialog for modified DFM files and it uses the Vista+ taskbar progress feature.

More information about DFMCheck:
https://www.idefixpack.de/blog/ide-tools/dfmcheck/

Download:

The IDE Fix Pack 6.0 BETA for XE2-10Seattle focuses on the Win64 compiler’s compile speed. It not only uses SSE2-SSE4.1 instructions to increase the compiler’s performance but it also optimizes for the most common cases. Micro optimizations are used for tight loops and functions that are called a million times.

Even with this patch the Win64 compiler isn’t on par with the Win32 compiler’s speed, but the difference isn’t that huge any more and there are still some possible optimization. But it takes a lot of time to analyze those and write the patches. And I if I would hold back the version 6.0 till all of those are completed, you will never see a version 6.0.

Because those changes to the compiler may intro bugs, I’m not releasing a gold version but a BETA version. That means that this isn’t meant for production use.

Don’t forgot: I’m not Embarcadero and I’m not fixing somebody’s pet bug. This BETA is all about the Win64 compiler speed optimizations. So please don’t report bugs (in the comments, at Google+, email) that aren’t related to the Win64 compiler speed optimizations. If the compiler outputs defect code with and without my patches, I won’t (and can’t) help you.

BETA Download: