[analyzer] Creating standard Sphinx documentation

The lack of documentation has been a long standing issue in the Static Analyzer,
and one of the leading reasons behind this was a lack of good documentation
infrastucture.

This lead serious drawbacks, such as
* Not having proper release notes for years
* Not being able to have a sensible auto-generated checker documentations (which
lead to most of them not having any)
* The HTML website that has to updated manually is a chore, and has been
outdated for a long while
* Many design discussions are now hidden in phabricator revisions

This patch implements a new documentation infrastucture using Sphinx, like most
of the other subprojects in LLVM. It transformed some pages as a proof-of-
concept, with many others to follow in later patches. The eventual goal is to
preserve the original website's (https://clang-analyzer.llvm.org/) frontpage,
but move everything else to the new format.

Some other ideas, like creating a unipage for each checker (similar to how
clang-tidy works now), are also being discussed.

Patch by Dániel Krupp!

Differential Revision: https://reviews.llvm.org/D54429

llvm-svn: 353126

1 files changed, 41 insertions, 0 deletions

diff --git a/clang/docs/analyzer/checkers/newdelete_example.cpp b/clang/docs/analyzer/checkers/newdelete_example.cpp
new file mode 100644
index 00000000000..b26ddcb3d96
--- /dev/null
+++ b/clang/docs/analyzer/checkers/newdelete_example.cpp
@@ -0,0 +1,41 @@
+void f(int *p);
+
+void testUseMiddleArgAfterDelete(int *p) {
+  delete p;
+  f(p); // warn: use after free
+}
+
+class SomeClass {
+public:
+  void f();
+};
+
+void test() {
+  SomeClass *c = new SomeClass;
+  delete c;
+  c->f(); // warn: use after free
+}
+
+void test() {
+  int *p = (int *)__builtin_alloca(sizeof(int));
+  delete p; // warn: deleting memory allocated by alloca
+}
+
+void test() {
+  int *p = new int;
+  delete p;
+  delete p; // warn: attempt to free released
+}
+
+void test() {
+  int i;
+  delete &i; // warn: delete address of local
+}
+
+void test() {
+  int *p = new int[1];
+  delete[] (++p);
+    // warn: argument to 'delete[]' is offset by 4 bytes
+    // from the start of memory allocated by 'new[]'
+}
+