forked from OSchip/llvm-project
51 lines
1.6 KiB
ReStructuredText
51 lines
1.6 KiB
ReStructuredText
llvm-diff - LLVM structural 'diff'
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==================================
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.. program:: llvm-diff
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SYNOPSIS
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--------
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**llvm-diff** [*options*] *module 1* *module 2* [*global name ...*]
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DESCRIPTION
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-----------
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**llvm-diff** compares the structure of two LLVM modules, primarily
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focusing on differences in function definitions. Insignificant
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differences, such as changes in the ordering of globals or in the
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names of local values, are ignored.
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An input module will be interpreted as an assembly file if its name
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ends in '.ll'; otherwise it will be read in as a bitcode file.
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If a list of global names is given, just the values with those names
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are compared; otherwise, all global values are compared, and
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diagnostics are produced for globals which only appear in one module
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or the other.
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**llvm-diff** compares two functions by comparing their basic blocks,
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beginning with the entry blocks. If the terminators seem to match,
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then the corresponding successors are compared; otherwise they are
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ignored. This algorithm is very sensitive to changes in control flow,
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which tend to stop any downstream changes from being detected.
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**llvm-diff** is intended as a debugging tool for writers of LLVM
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passes and frontends. It does not have a stable output format.
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EXIT STATUS
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-----------
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If **llvm-diff** finds no differences between the modules, it will exit
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with 0 and produce no output. Otherwise it will exit with a non-zero
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value.
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BUGS
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----
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Many important differences, like changes in linkage or function
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attributes, are not diagnosed.
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Changes in memory behavior (for example, coalescing loads) can cause
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massive detected differences in blocks.
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