Apple OSX Support

[paranlee]

If Apple were to making an next Vision Pro, they would have no choice but to use uftrace for Verifying the deterministic software behavior and performance measurement.

I found the Apple clang version 15.0.0 block the -pg options(no error message but when we do, there was no mcount or someting like that on objdump -dS assembly codes), so i tried to -finstrument-functions

$ uname -a

Darwin MacBookAir 23.2.0 Darwin Kernel Version 23.2.0:
Wed Nov 15 21:59:33 PST 2023; root:xnu-10002.61.3~2/RELEASE_ARM64_T8112 arm64

$ clang -v
Apple clang version 15.0.0 (clang-1500.1.0.2.5)
Target: arm64-apple-darwin23.2.0

Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

$ ./HelloMac

[MyLib.c] initializer()

Enter:

0, __cyg_profile_func_enter: fn = 0x1020ebef8, caller = 0x181ecd0e0

Hello, World!

Enter:

1, __cyg_profile_func_enter: fn = 0x1020ebe80, caller = 0x1020ebf58

Enter:

2, __cyg_profile_func_enter: fn = 0x1020ebe28, caller = 0x1020ebeb8

Exit:

1, __cyg_profile_func_exit: fn = 0x1020ebe28, caller = 0x1020ebeb8

Enter:

2, __cyg_profile_func_enter: fn = 0x1020ebe28, caller = 0x1020ebec4

Exit:

1, __cyg_profile_func_exit: fn = 0x1020ebe28, caller = 0x1020ebec4

Exit:

0, __cyg_profile_func_exit: fn = 0x1020ebe80, caller = 0x1020ebf58

Exit:

-1, __cyg_profile_func_exit: fn = 0x1020ebef8, caller = 0x181ecd0e0

[MyLib.c] finalizer()

My PoC Codes are right here.

Apple hide the __cyg_profile_func_enter, __cyg_profile_func_exit in there libc.

So when we compiled -finstrument-functions option only, that makes ld linking error.

ld: undefined symbols: ___cyg_profile_func_enter

MyLib implements the __cyg_profile_func_enter, __cyg_profile_func_exit [1].

/* File: MyLib.h

 * Interface to MyLib.lib 1.0.

 *************************************/

void __cyg_profile_func_enter(void *, void *); // __attribute__((no_instrument_function));

void __cyg_profile_func_exit(void *, void *); // __attribute__((no_instrument_function));

/* File: MyLib.c

 * Compile with -fvisibility=hidden.

 **********************************/

#include "MyLib.h"
#include <stdio.h>
#include <string.h>

#define EXPORT __attribute__((visibility("default")))

#define sustainable(fn, caller) \
        do{ \
            printf("%d, %s: fn = %p, caller = %p\n", depth_, __FUNCTION__, fn, caller); \
        } while(0)

int depth_ = -1;

// Initializer.
__attribute__((constructor))
static void initializer(void)
{
    printf("[%s] initializer()\n", __FILE__);
}

// Finalizer.
__attribute__((destructor))
static void finalizer(void)
{
    printf("[%s] finalizer()\n", __FILE__);
}

EXPORT
void __cyg_profile_func_enter(void *fn, void *caller)
{
        printf("Enter:\n");
        depth_++;
        sustainable(fn, caller);
}

EXPORT
void __cyg_profile_func_exit(void *fn, void *caller)
{
        printf("Exit:\n");
        depth_--;
        sustainable(fn, caller);
}

We need to our source codes building with shared library MyLib.lib.

$ clang -shared MyLib.c -current_version 1.0 -fvisibility=hidden -o MyLib.lib

Test code main.c.

//  main.c
//  HelloMac
//
//  Created by Paran Lee on 12/17/23.
//

#include <stdio.h>

int func2(int arg1)
{
    return 2 + arg1;
}

int func1(int arg1)
{

    int val1 = func2(arg1);
    int val2 = func2(val1);

    return val1 + val2;
}

int main(int argc, const char * argv[])
{

    printf("Hello, World!\n");

    func1(1);

    return 0;
}

Then

$ clang -v -O0 -ggdb -finstrument-functions main.c -o HelloMac MyLib.lib

Apple clang version 15.0.0 (clang-1500.1.0.2.5)

Target: arm64-apple-darwin23.2.0

Thread model: posix

InstalledDir: /Library/Developer/CommandLineTools/usr/bin

 "/Library/Developer/CommandLineTools/usr/bin/clang" -cc1 -triple arm64-apple-macosx14.0.0 -Wundef-prefix=TARGET_OS_ -Wdeprecated-objc-isa-usage -Werror=deprecated-objc-isa-usage -Werror=implicit-function-declaration -emit-obj -mrelax-all --mrelax-relocations -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name main.c -mrelocation-model pic -pic-level 2 -mframe-pointer=non-leaf -fno-strict-return -ffp-contract=on -fno-rounding-math -funwind-tables=1 -fobjc-msgsend-selector-stubs -target-sdk-version=14.2 -fvisibility-inlines-hidden-static-local-var -target-cpu apple-m1 -target-feature +v8.5a -target-feature +crc -target-feature +lse -target-feature +rdm -target-feature +crypto -target-feature +dotprod -target-feature +fp-armv8 -target-feature +neon -target-feature +fp16fml -target-feature +ras -target-feature +rcpc -target-feature +zcm -target-feature +zcz -target-feature +fullfp16 -target-feature +sm4 -target-feature +sha3 -target-feature +sha2 -target-feature +aes -target-abi darwinpcs -mllvm -treat-scalable-fixed-error-as-warning -debug-info-kind=standalone -dwarf-version=4 -debugger-tuning=gdb -target-linker-version 1022.1 -v -finstrument-functions -fcoverage-compilation-dir=/Users/yunseong/Desktop/cpp-project/HelloMac/HelloMac -resource-dir /Library/Developer/CommandLineTools/usr/lib/clang/15.0.0 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -I/usr/local/include -internal-isystem /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/local/include -internal-isystem /Library/Developer/CommandLineTools/usr/lib/clang/15.0.0/include -internal-externc-isystem /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include -internal-externc-isystem /Library/Developer/CommandLineTools/usr/include -O0 -Wno-reorder-init-list -Wno-implicit-int-float-conversion -Wno-c99-designator -Wno-final-dtor-non-final-class -Wno-extra-semi-stmt -Wno-misleading-indentation -Wno-quoted-include-in-framework-header -Wno-implicit-fallthrough -Wno-enum-enum-conversion -Wno-enum-float-conversion -Wno-elaborated-enum-base -Wno-reserved-identifier -Wno-gnu-folding-constant -fdebug-compilation-dir=/Users/yunseong/Desktop/cpp-project/HelloMac/HelloMac -ferror-limit 19 -stack-protector 1 -fstack-check -mdarwin-stkchk-strong-link -fblocks -fencode-extended-block-signature -fregister-global-dtors-with-atexit -fgnuc-version=4.2.1 -fmax-type-align=16 -fcommon -fcolor-diagnostics -clang-vendor-feature=+disableNonDependentMemberExprInCurrentInstantiation -fno-odr-hash-protocols -clang-vendor-feature=+enableAggressiveVLAFolding -clang-vendor-feature=+revert09abecef7bbf -clang-vendor-feature=+thisNoAlignAttr -clang-vendor-feature=+thisNoNullAttr -mllvm -disable-aligned-alloc-awareness=1 -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /var/folders/j0/gv5zl6kd1t549fwnw88p9bl40000gn/T/main-1bc209.o -x c main.c

clang -cc1 version 15.0.0 (clang-1500.1.0.2.5) default target arm64-apple-darwin23.2.0

ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/local/include"
ignoring nonexistent directory "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/Library/Frameworks"

#include "..." search starts here:
#include <...> search starts here:

 /Library/Developer/CommandLineTools/usr/lib/clang/15.0.0/include
 /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include
 /Library/Developer/CommandLineTools/usr/include
 /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks (framework directory)

End of search list.

 "/Library/Developer/CommandLineTools/usr/bin/ld" -demangle -lto_library /Library/Developer/CommandLineTools/usr/lib/libLTO.dylib -no_deduplicate -dynamic -arch arm64 -platform_version macos 14.0.0 14.2 -syslibroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -O0 -o HelloMac -L/usr/local/lib /var/folders/j0/gv5zl6kd1t549fwnw88p9bl40000gn/T/main-1bc209.o MyLib.lib -lSystem /Library/Developer/CommandLineTools/usr/lib/clang/15.0.0/lib/darwin/libclang_rt.osx.a

 "/Library/Developer/CommandLineTools/usr/bin/dsymutil" -o HelloMac.dSYM HelloMac

I could found the reference that Apple used -finstrument-functions more than 10 years ago old age [2].

Saturn profiler -> macOS 10.15 Catalina

Apple' new profiler Instruments will replace the Saturn profiler
Instruments -> macOS 10.10 Yosemite

When I investigated the compile time what Apple clang version 15.0.0 looks library, I need some trace tool like strace so I can using ktrace on my Apple M2 [3].

[1] https://developer.apple.com/library/archive/documentation/DeveloperTools/Conceptual/DynamicLibraries/100-Articles/CreatingDynamicLibraries.html
[2] https://adrianboeing.blogspot.com/2010/02/profiling-on-mac-osx-with-saturn.html
[3] https://stackoverflow.com/questions/31045575/how-to-trace-system-calls-of-a-program-in-mac-os-x

[paranlee]

Checklist from @honggyukim

To use uftrace on a Mac, we need to do the following.

• Make sure we have LD_PRELOAD or an alternative technique.
  • Dynamic Lib injection on OSX: Linux LD_PRELOAD ≒ OSX DYLD_INSERT_LIBRARIES
  • Microsoft mimalloc use DYLD_INSERT_LIBRARIES
• Write code for the Mac's Mach-O file format to replace Linux's ELF file format.
  Isolate Linux-dependent functions with #ifdef or other methods
  • A similar implementation is needed for Mach-O, a Mac file format.
  • The ELF file format related processing is located in the path below.
    • If we have libelf: https://github.com/namhyung/uftrace/blob/master/utils/symbol-libelf.c
    • If not: https://github.com/namhyung/uftrace/blob/master/utils/symbol-rawelf.c
• Various other testing and debugging