Chunks of Bytecode > 자유게시판

To disassemble a chunk, we print a little header (so we can tell which chunk we’re looking at) and then crank through the bytecode, disassembling each instruction. After which it gather E & P header properties, allocates regions possibly populating/sorting it, iterates over all P headers to compare them, Pool Table Size & cleans up. Then it iterates over all codeblock’s instructions attempting to decompose any RETURN, ASSIGN, CALL, or ASM instruction. Following the prelude it outputs the instructions it has planned to allocate/initialize stack vars making sure to properly handle SSA partitions. Alongside a logging system, imports, branching, utils for handling commandline args, deconstructing lists, debugging, stack operations, redirecting output, dependency resolution, ASCII processing, version number processing, sets, & an initialization routine. The functions for reading those input lines can be overriden by commandline flags & handles splitting args. A fourth non-conditional iteration computes the instructs, skips metadata (notes/barriers/labels/debugs) & deleted instructs, handles sizing jump tables & literal assembly specially, otherwise take into consideration the previously computed "delay slots" or clobbering.

A second iteration updates the function type signatures. Otherwise updates some globals or outputs errors. Since all we passed in was a bare pointer to the first byte of memory, what does it mean to "update" the block’s size? As with the bytecode array in Chunk, this struct wraps a pointer to an array along with its allocated capacity and the number of elements in use. In addition to the array itself, we keep two numbers: the number of elements in the array we have allocated ("capacity") and how many of those allocated entries are actually in use ("count"). Those tell realloc() to resize the previously allocated block. Under the hood, the memory allocator maintains additional bookkeeping information for each block of heap-allocated memory, including its size. In order to get the performance we want, the important part is that it scales based on the old size. 1. Copy the existing elements from the old array to the new one. We have only one instruction right now, but this switch will grow throughout the rest of the book. From this tiny seed, we will grow our entire VM.

Often we want to treat entire directories/folders as individual files we can send over the internet, always have. For each loop it initializes it’s IV analysis & verifies it can optimize this loop. With additional collections initialized it iterates over every loop. After unflagging instructions & PHIs as having been visited & with an allocator (and, for reruns the loop indexes) initialized it iterates over codeblocks in reverse postorder locating bundles of codeblocks with the same dominator. Runtime & compiletime optionally it iterates over instructs a third time & the range of "SHUIDs" within. Otherwise it iterates to the next group (via tree traversal) then group (via repeated tree traversal). We can create a chunk, write an instruction to it, and then extract that instruction back out. Given a chunk, it will print out all of the instructions in it. The implementations will probably give you déjà vu. Routing all of those operations through a single function will be important later when we add a garbage collector that needs to keep track of how much memory is in use. When we add an element, if the count is less than the capacity, then there is already available space in the array.

Now that we have growable arrays of values, we can add one to Chunk to store the chunk’s constants. Back to the question of where to store constants in a chunk. C doesn’t have constructors, so we declare a function to initialize a new chunk. As with our bytecode array, the compiler doesn’t know how big the array needs to be ahead of time. Since C doesn’t have generic data structures, we’ll write another dynamic array data structure, this time for Value. Several variations of Huffman Coding, involving taking a histogram, greedily pairing up least-common symbols, output the reformatted codebook, & (could happen earlier in fastpaths) rewrites data according to that codebook. 7. Tell the output to repaint. For each section (round 2) it retrieves various properties upon successfully retrieving the section whilst applying any requested compression, creates a new section in the output ELF file, & copies the various data over to it with minor tweaks (and more compression!). Applying a chain involves two steps: 1) final planning/coalescing & 2) mutating the code. Initializing a raw encoder involves (before setting some flags in an array) involves validating an array of filters whilst computing its length before reencoding it via a callback & linear scan through a constant array to contain methodtables.