Xcode Build Setting 整理（二）

Apple Clang

Apple Clang - Address Sanitizer 清扫

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Summary

Check for C++ container overflow when Address Sanitizer is enabled. This check requires the entire application to be built with Address Sanitizer. If not, it may report false positives.

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Declaration

CLANG_ADDRESS_SANITIZER_CONTAINER_OVERFLOW

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Value Type

Boolean

Apple Clang - Code Generation 产生

Debug Information Level (CLANG_DEBUG_INFORMATION_LEVEL)

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Summary

Toggles the amount of debug information emitted when debug symbols are enabled. This can impact the size of the generated debug information, which may matter in some cases for large projects, such as when using LTO.

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Declaration

CLANG_DEBUG_INFORMATION_LEVEL

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Value Type

Enumeration (String)

Enable Additional Vector Extensions

Summary

Enables the use of extended vector instructions. Only used when targeting Intel architectures.

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Declaration

CLANG_X86_VECTOR_INSTRUCTIONS

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Value Type

Enumeration (String)

Enable Code Coverage Support

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Summary

Enables building with code coverage instrumentation. This is only used when the build has code coverage enabled, which is typically done via the Xcode scheme settings.

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Declaration

CLANG_ENABLE_CODE_COVERAGE

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Value Type

Boolean

Enforce Strict Aliasing

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Summary

Optimize code by making more aggressive assumptions about whether pointers can point to the same objects as other pointers. Programs that use pointers a lot may benefit from this, but programs that don't strictly follow the ISO C rules about the type with which an object may be accessed may behave unexpectedly.

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Declaration

GCC_STRICT_ALIASING

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Value Type

Boolean

Generate Debug Symbols

是否生成 Debug 符号文件，生成的时候可以设置 DEBUG_INFORMATION_FORMAT

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Summary

Enables or disables generation of debug symbols. When debug symbols are enabled, the level of detail can be controlled by the `DEBUG_INFORMATION_FORMAT` setting.

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Declaration

GCC_GENERATE_DEBUGGING_SYMBOLS

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Value Type

Boolean

Generate Legacy Test Coverage Files

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Summary

Activating this setting causes a `notes` file to be produced that the `gcov` code-coverage utility can use to show program coverage.

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Declaration

GCC_GENERATE_TEST_COVERAGE_FILES

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Value Type

Boolean

Generate Position-Dependent Code

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Summary

Faster function calls for applications. Not appropriate for shared libraries, which need to be position-independent.

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Declaration

GCC_DYNAMIC_NO_PIC

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Value Type

Boolean

Inline Methods Hidden

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Summary

When enabled, out-of-line copies of inline methods are declared `private extern`.

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Declaration

GCC_INLINES_ARE_PRIVATE_EXTERN

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Value Type

Boolean

Instrument Program Flow

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Summary

Activating this setting indicates that code should be added so program flow arcs are instrumented.

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Declaration

GCC_INSTRUMENT_PROGRAM_FLOW_ARCS

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Value Type

Boolean

Kernel Development Mode

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Summary

Activating this setting enables kernel development mode.

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Declaration

GCC_ENABLE_KERNEL_DEVELOPMENT

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Value Type

Boolean

Link-Time Optimization

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Summary

Enabling this setting allows optimization across file boundaries during linking. * *No:* Disabled. Do not use link-time optimization. * *Monolithic Link-Time Optimization:* This mode performs monolithic link-time optimization of binaries, combining all executable code into a single unit and running aggressive compiler optimizations. * *Incremental Link-Time Optimization:* This mode performs partitioned link-time optimization of binaries, inlining between compilation units and running aggressive compiler optimizations on each unit in parallel. This enables fast incremental builds and uses less memory than Monolithic LTO.

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Declaration

LLVM_LTO

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Value Type

Enumeration (String)

Make Strings Read-Only

字符串常量重复使用，也就是在mach-o中字符串常量是在同一个区域内，使用的时候通过指针查找

Summary

Reuse string literals.

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Declaration

GCC_REUSE_STRINGS

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Value Type

Boolean

No Common Blocks

Summary

In C, allocate even uninitialized global variables in the data section of the object file, rather than generating them as common blocks. This has the effect that if the same variable is declared (without `extern`) in two different compilations, you will get an error when you link them.

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Declaration

GCC_NO_COMMON_BLOCKS

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Value Type

Boolean

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例子

GCC_NO_COMMON_BLOCKS=YES

Optimization Level

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Summary

Specifies the degree to which the generated code is optimized for speed and binary size. * *None:* Do not optimize. [-O0] With this setting, the compiler's goal is to reduce the cost of compilation and to make debugging produce the expected results. Statements are independent—if you stop the program with a breakpoint between statements, you can then assign a new value to any variable or change the program counter to any other statement in the function and get exactly the results you would expect from the source code. * *Fast:* Optimizing compilation takes somewhat more time, and a lot more memory for a large function. [-O1] With this setting, the compiler tries to reduce code size and execution time, without performing any optimizations that take a great deal of compilation time. In Apple's compiler, strict aliasing, block reordering, and inter-block scheduling are disabled by default when optimizing. * *Faster:* The compiler performs nearly all supported optimizations that do not involve a space-speed tradeoff. [-O2] With this setting, the compiler does not perform loop unrolling or function inlining, or register renaming. As compared to the `Fast` setting, this setting increases both compilation time and the performance of the generated code. * *Fastest:* Turns on all optimizations specified by the `Faster` setting and also turns on function inlining and register renaming options. This setting may result in a larger binary. [-O3] * *Fastest, Smallest:* Optimize for size. This setting enables all `Faster` optimizations t