diff options
Diffstat (limited to 'docs/analyzer/IPA.txt')
| -rw-r--r-- | docs/analyzer/IPA.txt | 41 |
1 files changed, 35 insertions, 6 deletions
diff --git a/docs/analyzer/IPA.txt b/docs/analyzer/IPA.txt index 4cffcb7454..01e73cec7f 100644 --- a/docs/analyzer/IPA.txt +++ b/docs/analyzer/IPA.txt @@ -46,11 +46,14 @@ Each of these modes implies that all the previous member function kinds will be inlined as well; it doesn't make sense to inline destructors without inlining constructors, for example. -The default c++-inlining mode is 'constructors', meaning that member functions, -overloaded operators, and some constructors will be inlined. If a type has a -non-trivial destructor, however, its constructor will not be inlined. Note that -no C++ member functions will be inlined under -analyzer-config ipa=none or --analyzer-config ipa=basic-inlining. +The default c++-inlining mode is 'destructors', meaning that all member +functions with visible definitions will be considered for inlining. In some +cases the analyzer may still choose not to inline the function. + +Note that under 'constructors', constructors for types with non-trivial +destructors will not be inlined. Additionally, no C++ member functions will be +inlined under -analyzer-config ipa=none or -analyzer-config ipa=basic-inlining, +regardless of the setting of the c++-inlining mode. ### c++-template-inlining ### @@ -73,7 +76,8 @@ considered for inlining. -analyzer-config c++-template-inlining=[true | false] -Currently, C++ standard library functions are NOT considered for inlining by default. +Currently, C++ standard library functions are considered for inlining by +default. The standard library functions and the STL in particular are used ubiquitously enough that our tolerance for false positives is even lower here. A false @@ -81,6 +85,31 @@ positive due to poor modeling of the STL leads to a poor user experience, since most users would not be comfortable adding assertions to system headers in order to silence analyzer warnings. +### c++-container-inlining ### + +This option controls whether constructors and destructors of "container" types +should be considered for inlining. + + -analyzer-config c++-container-inlining=[true | false] + +Currently, these constructors and destructors are NOT considered for inlining +by default. + +The current implementation of this setting checks whether a type has a member +named 'iterator' or a member named 'begin'; these names are idiomatic in C++, +with the latter specified in the C++11 standard. The analyzer currently does a +fairly poor job of modeling certain data structure invariants of container-like +objects. For example, these three expressions should be equivalent: + + std::distance(c.begin(), c.end()) == 0 + c.begin() == c.end() + c.empty()) + +Many of these issues are avoided if containers always have unknown, symbolic +state, which is what happens when their constructors are treated as opaque. +In the future, we may decide specific containers are "safe" to model through +inlining, or choose to model them directly using checkers instead. + Basics of Implementation ----------------------- |