summaryrefslogtreecommitdiffstats
path: root/gnu/llvm/docs/CommandGuide/llvm-diff.rst
diff options
context:
space:
mode:
authorpascal <pascal@openbsd.org>2016-09-03 22:46:54 +0000
committerpascal <pascal@openbsd.org>2016-09-03 22:46:54 +0000
commitb5500b9ca0102f1ccaf32f0e77e96d0739aded9b (patch)
treee1b7ebb5a0231f9e6d8d3f6f719582cebd64dc98 /gnu/llvm/docs/CommandGuide/llvm-diff.rst
parentclarify purpose of src/gnu/ directory. (diff)
downloadwireguard-openbsd-b5500b9ca0102f1ccaf32f0e77e96d0739aded9b.tar.xz
wireguard-openbsd-b5500b9ca0102f1ccaf32f0e77e96d0739aded9b.zip
Use the space freed up by sparc and zaurus to import LLVM.
ok hackroom@
Diffstat (limited to 'gnu/llvm/docs/CommandGuide/llvm-diff.rst')
-rw-r--r--gnu/llvm/docs/CommandGuide/llvm-diff.rst56
1 files changed, 56 insertions, 0 deletions
diff --git a/gnu/llvm/docs/CommandGuide/llvm-diff.rst b/gnu/llvm/docs/CommandGuide/llvm-diff.rst
new file mode 100644
index 00000000000..991d4fece04
--- /dev/null
+++ b/gnu/llvm/docs/CommandGuide/llvm-diff.rst
@@ -0,0 +1,56 @@
+llvm-diff - LLVM structural 'diff'
+==================================
+
+
+SYNOPSIS
+--------
+
+
+**llvm-diff** [*options*] *module 1* *module 2* [*global name ...*]
+
+
+DESCRIPTION
+-----------
+
+
+**llvm-diff** compares the structure of two LLVM modules, primarily
+focusing on differences in function definitions. Insignificant
+differences, such as changes in the ordering of globals or in the
+names of local values, are ignored.
+
+An input module will be interpreted as an assembly file if its name
+ends in '.ll'; otherwise it will be read in as a bitcode file.
+
+If a list of global names is given, just the values with those names
+are compared; otherwise, all global values are compared, and
+diagnostics are produced for globals which only appear in one module
+or the other.
+
+**llvm-diff** compares two functions by comparing their basic blocks,
+beginning with the entry blocks. If the terminators seem to match,
+then the corresponding successors are compared; otherwise they are
+ignored. This algorithm is very sensitive to changes in control flow,
+which tend to stop any downstream changes from being detected.
+
+**llvm-diff** is intended as a debugging tool for writers of LLVM
+passes and frontends. It does not have a stable output format.
+
+
+EXIT STATUS
+-----------
+
+
+If **llvm-diff** finds no differences between the modules, it will exit
+with 0 and produce no output. Otherwise it will exit with a non-zero
+value.
+
+
+BUGS
+----
+
+
+Many important differences, like changes in linkage or function
+attributes, are not diagnosed.
+
+Changes in memory behavior (for example, coalescing loads) can cause
+massive detected differences in blocks.