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author | Tom Roeder <tmroeder@google.com> | 2014-06-05 19:29:43 +0000 |
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committer | Tom Roeder <tmroeder@google.com> | 2014-06-05 19:29:43 +0000 |
commit | 5d0f7af3dc42d7bc843858317fba3bb91c44d68f (patch) | |
tree | c525924c6e517a0e74dc7c5329096c68c6a27a2f /docs/LangRef.rst | |
parent | 4db3ad47fc58e3cc2b8227b4e6ea0c126338463e (diff) | |
download | llvm-5d0f7af3dc42d7bc843858317fba3bb91c44d68f.tar.gz llvm-5d0f7af3dc42d7bc843858317fba3bb91c44d68f.tar.bz2 llvm-5d0f7af3dc42d7bc843858317fba3bb91c44d68f.tar.xz |
Add a new attribute called 'jumptable' that creates jump-instruction tables for functions marked with this attribute.
It includes a pass that rewrites all indirect calls to jumptable functions to pass through these tables.
This also adds backend support for generating the jump-instruction tables on ARM and X86.
Note that since the jumptable attribute creates a second function pointer for a
function, any function marked with jumptable must also be marked with unnamed_addr.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210280 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs/LangRef.rst')
-rw-r--r-- | docs/LangRef.rst | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/docs/LangRef.rst b/docs/LangRef.rst index d76fc0d3af..6beb9652ed 100644 --- a/docs/LangRef.rst +++ b/docs/LangRef.rst @@ -1020,6 +1020,14 @@ example: inlining this function is desirable (such as the "inline" keyword in C/C++). It is just a hint; it imposes no requirements on the inliner. +``jumptable`` + This attribute indicates that the function should be added to a + jump-instruction table at code-generation time, and that all address-taken + references to this function should be replaced with a reference to the + appropriate jump-instruction-table function pointer. Note that this creates + a new pointer for the original function, which means that code that depends + on function-pointer identity can break. So, any function annotated with + ``jumptable`` must also be ``unnamed_addr``. ``minsize`` This attribute suggests that optimization passes and code generator passes make choices that keep the code size of this function as small |