[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outdated for a long while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, 37 insertions, 0 deletions

diff --git a/clang/docs/analyzer/checkers/unix_api_example.c b/clang/docs/analyzer/checkers/unix_api_example.c
new file mode 100644
index 00000000000..66ed56fd866
--- /dev/null
+++ b/clang/docs/analyzer/checkers/unix_api_example.c
@@ -0,0 +1,37 @@
+
+// Currently the check is performed for apple targets only.
+void test(const char *path) {
+  int fd = open(path, O_CREAT);
+    // warn: call to 'open' requires a third argument when the
+    // 'O_CREAT' flag is set
+}
+
+void f();
+
+void test() {
+  pthread_once_t pred = {0x30B1BCBA, {0}};
+  pthread_once(&pred, f);
+    // warn: call to 'pthread_once' uses the local variable
+}
+
+void test() {
+  void *p = malloc(0); // warn: allocation size of 0 bytes
+}
+
+void test() {
+  void *p = calloc(0, 42); // warn: allocation size of 0 bytes
+}
+
+void test() {
+  void *p = malloc(1);
+  p = realloc(p, 0); // warn: allocation size of 0 bytes
+}
+
+void test() {
+  void *p = alloca(0); // warn: allocation size of 0 bytes
+}
+
+void test() {
+  void *p = valloc(0); // warn: allocation size of 0 bytes
+}
+