diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/AttributeReference.rst | 1 | ||||
| -rw-r--r-- | docs/ReleaseNotes.rst | 27 | ||||
| -rw-r--r-- | docs/UsersManual.rst | 10 |
3 files changed, 37 insertions, 1 deletions
diff --git a/docs/AttributeReference.rst b/docs/AttributeReference.rst index d7a3f74f83fb..db4812afdaa0 100644 --- a/docs/AttributeReference.rst +++ b/docs/AttributeReference.rst @@ -456,6 +456,7 @@ warnings or errors at compile-time if calls to the attributed function meet certain user-defined criteria. For example: .. code-block:: c + void abs(int a) __attribute__((diagnose_if(a >= 0, "Redundant abs call", "warning"))); void must_abs(int a) diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst index 5b035cd3320f..25ea577ba519 100644 --- a/docs/ReleaseNotes.rst +++ b/docs/ReleaseNotes.rst @@ -46,8 +46,35 @@ Major New Features clang to emit a warning or error if a function call meets one or more user-specified conditions. +- Enhanced devirtualization with + `-fstrict-vtable-pointers <UsersManual.html#cmdoption-fstrict-vtable-pointers>`_. + Clang devirtualizes across different basic blocks, like loops: + + .. code-block:: c++ + + struct A { + virtual void foo(); + }; + void indirect(A &a, int n) { + for (int i = 0 ; i < n; i++) + a.foo(); + } + void test(int n) { + A a; + indirect(a, n); + } + + - ... +Improvements to ThinLTO (-flto=thin) +------------------------------------ +- Integration with profile data (PGO). When available, profile data enables + more accurate function importing decisions, as well as cross-module indirect + call promotion. +- Significant build-time and binary-size improvements when compiling with debug + info (-g). + Improvements to Clang's diagnostics ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/docs/UsersManual.rst b/docs/UsersManual.rst index 3adbfe059f89..04023dd20602 100644 --- a/docs/UsersManual.rst +++ b/docs/UsersManual.rst @@ -1097,6 +1097,14 @@ are listed below. the behavior of sanitizers in the ``cfi`` group to allow checking of cross-DSO virtual and indirect calls. + +.. option:: -fstrict-vtable-pointers + + Enable optimizations based on the strict rules for overwriting polymorphic + C++ objects, i.e. the vptr is invariant during an object's lifetime. + This enables better devirtualization. Turned off by default, because it is + still experimental. + .. option:: -ffast-math Enable fast-math mode. This defines the ``__FAST_MATH__`` preprocessor @@ -2645,7 +2653,7 @@ Execute ``clang-cl /?`` to see a list of supported options: (overridden by LLVM_PROFILE_FILE env var) -fprofile-instr-generate Generate instrumented code to collect execution counts into default.profraw file - (overriden by '=' form of option or LLVM_PROFILE_FILE env var) + (overridden by '=' form of option or LLVM_PROFILE_FILE env var) -fprofile-instr-use=<value> Use instrumentation data for profile-guided optimization -fsanitize-blacklist=<value> |