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LLVM 10
author Shinji KONO <kono@ie.u-ryukyu.ac.jp>
date Wed, 14 Aug 2019 16:55:33 +0900
parents 95c75e76d11b
children
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1 llvm-diff - LLVM structural 'diff'
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2 ==================================
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4 .. program:: llvm-diff
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6 SYNOPSIS
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7 --------
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9 **llvm-diff** [*options*] *module 1* *module 2* [*global name ...*]
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11 DESCRIPTION
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12 -----------
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14 **llvm-diff** compares the structure of two LLVM modules, primarily
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15 focusing on differences in function definitions. Insignificant
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16 differences, such as changes in the ordering of globals or in the
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17 names of local values, are ignored.
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18
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19 An input module will be interpreted as an assembly file if its name
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20 ends in '.ll'; otherwise it will be read in as a bitcode file.
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21
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22 If a list of global names is given, just the values with those names
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23 are compared; otherwise, all global values are compared, and
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24 diagnostics are produced for globals which only appear in one module
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25 or the other.
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27 **llvm-diff** compares two functions by comparing their basic blocks,
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28 beginning with the entry blocks. If the terminators seem to match,
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29 then the corresponding successors are compared; otherwise they are
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30 ignored. This algorithm is very sensitive to changes in control flow,
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31 which tend to stop any downstream changes from being detected.
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33 **llvm-diff** is intended as a debugging tool for writers of LLVM
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34 passes and frontends. It does not have a stable output format.
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35
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36 EXIT STATUS
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37 -----------
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39 If **llvm-diff** finds no differences between the modules, it will exit
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40 with 0 and produce no output. Otherwise it will exit with a non-zero
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41 value.
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43 BUGS
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44 ----
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46 Many important differences, like changes in linkage or function
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47 attributes, are not diagnosed.
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49 Changes in memory behavior (for example, coalescing loads) can cause
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50 massive detected differences in blocks.