48 lines
1.6 KiB
C++
48 lines
1.6 KiB
C++
#ifndef COSMOPOLITAN_LIBC_RUNTIME_GC_H_
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#define COSMOPOLITAN_LIBC_RUNTIME_GC_H_
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#include "libc/calls/calls.h"
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#include "libc/nexgen32e/stackframe.h"
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#include "libc/runtime/runtime.h"
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#if !(__ASSEMBLER__ + __LINKER__ + 0)
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COSMOPOLITAN_C_START_
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/**
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* @fileoverview Cosmopolitan Return-Oriented Garbage Collector.
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*
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* This is the same thing as {@code std::unique_ptr<>} in C++ or the
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* {@code defer} keyword in Go. We harness the power of ROP for good
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* using very few lines of code.
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*/
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/**
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* Releases resource when function returns.
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*
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* @warning do not return a gc()'d pointer
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* @warning do not realloc() with gc()'d pointer
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*/
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#define gc(THING) defer((void *)weakfree, (void *)(THING))
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/**
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* Same as longjmp() but runs gc() / defer() destructors.
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*/
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void gclongjmp(jmp_buf, int) nothrow noreturn paramsnonnull();
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/**
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* Calls FN(ARG) when function returns.
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*/
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#define defer(FN, ARG) \
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({ \
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autotype(ARG) Arg = (ARG); \
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/* prevent weird opts like tail call */ \
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asm volatile("" : "+g"(Arg) : : "memory"); \
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__defer((struct StackFrame *)__builtin_frame_address(0), FN, Arg); \
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asm volatile("" : "+g"(Arg) : : "memory"); \
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Arg; \
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})
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void __defer(struct StackFrame *, void *, void *) hidden paramsnonnull((1, 2));
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COSMOPOLITAN_C_END_
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#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
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#endif /* COSMOPOLITAN_LIBC_RUNTIME_GC_H_ */
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