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| author | Piotr Padlewski <piotr.padlewski@gmail.com> | 2018-06-13 13:55:42 +0000 |
|---|---|---|
| committer | Piotr Padlewski <piotr.padlewski@gmail.com> | 2018-06-13 13:55:42 +0000 |
| commit | e368de364e1fa1dcd0f67a5fbb5ae5cbb0adae65 (patch) | |
| tree | 287bb854ba52a5cf2b6baa239b16e6c2c3e0ec9e /clang/docs | |
| parent | 60e3d582f664486507119dc2b7fc3a876b065664 (diff) | |
| download | bcm5719-llvm-e368de364e1fa1dcd0f67a5fbb5ae5cbb0adae65.tar.gz bcm5719-llvm-e368de364e1fa1dcd0f67a5fbb5ae5cbb0adae65.zip | |
Add -fforce-emit-vtables
Summary:
In many cases we can't devirtualize
because definition of vtable is not present. Most of the
time it is caused by inline virtual function not beeing
emitted. Forcing emitting of vtable adds a reference of these
inline virtual functions.
Note that GCC was always doing it.
Reviewers: rjmccall, rsmith, amharc, kuhar
Subscribers: llvm-commits, cfe-commits
Differential Revision: https://reviews.llvm.org/D47108
Co-authored-by: Krzysztof Pszeniczny <krzysztof.pszeniczny@gmail.com>
llvm-svn: 334600
Diffstat (limited to 'clang/docs')
| -rw-r--r-- | clang/docs/ClangCommandLineReference.rst | 6 | ||||
| -rw-r--r-- | clang/docs/ReleaseNotes.rst | 6 | ||||
| -rw-r--r-- | clang/docs/UsersManual.rst | 6 |
3 files changed, 18 insertions, 0 deletions
diff --git a/clang/docs/ClangCommandLineReference.rst b/clang/docs/ClangCommandLineReference.rst index 264729dd0f1..513128119e2 100644 --- a/clang/docs/ClangCommandLineReference.rst +++ b/clang/docs/ClangCommandLineReference.rst @@ -1934,6 +1934,12 @@ Set the default symbol visibility for all global declarations Enables whole-program vtable optimization. Requires -flto +.. option:: -fforce-emit-vtables, -fno-force-emit-vtables + +In order to improve devirtualization, forces emitting of vtables even in +modules where it isn't necessary. It causes more inline virtual functions +to be emitted. + .. option:: -fwrapv, -fno-wrapv Treat signed integer overflow as two's complement diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 84145554647..15ae73e859e 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -112,6 +112,12 @@ New Compiler Flags 'no-strict' option, Clang attempts to match the overflowing behavior of the target's native float-to-int conversion instructions. +- :option: `-fforce-emit-vtables` and `-fno-force-emit-vtables`. + + In order to improve devirtualization, forces emitting of vtables even in + modules where it isn't necessary. It causes more inline virtual functions + to be emitted. + - ... Deprecated Compiler Flags diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst index 9778b1654de..b1c286193cf 100644 --- a/clang/docs/UsersManual.rst +++ b/clang/docs/UsersManual.rst @@ -1269,6 +1269,12 @@ are listed below. devirtualization and virtual constant propagation, for classes with :doc:`hidden LTO visibility <LTOVisibility>`. Requires ``-flto``. +.. option:: -fforce-emit-vtables + + In order to improve devirtualization, forces emitting of vtables even in + modules where it isn't necessary. It causes more inline virtual functions + to be emitted. + .. option:: -fno-assume-sane-operator-new Don't assume that the C++'s new operator is sane. |
