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f4f4caab0e
I wanted a tiny scriptable meltdown proof way to run userspace programs and visualize how program execution impacts memory. It helps to explain how things like Actually Portable Executable works. It can show you how the GCC generated code is going about manipulating matrices and more. I didn't feel fully comfortable with Qemu and Bochs because I'm not smart enough to understand them. I wanted something like gVisor but with much stronger levels of assurances. I wanted a single binary that'll run, on all major operating systems with an embedded GPL barrier ZIP filesystem that is tiny enough to transpile to JavaScript and run in browsers too. https://justine.storage.googleapis.com/emulator625.mp4
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/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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struct StackFrame;
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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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