llvm-project/clang
Dean Michael Berris 1a5b10d5b4 [XRay][clang] Introduce -fxray-always-emit-customevents
Summary:
The -fxray-always-emit-customevents flag instructs clang to always emit
the LLVM IR for calls to the `__xray_customevent(...)` built-in
function. The default behaviour currently respects whether the function
has an `[[clang::xray_never_instrument]]` attribute, and thus not lower
the appropriate IR code for the custom event built-in.

This change allows users calling through to the
`__xray_customevent(...)` built-in to always see those calls lowered to
the corresponding LLVM IR to lay down instrumentation points for these
custom event calls.

Using this flag enables us to emit even just the user-provided custom
events even while never instrumenting the start/end of the function
where they appear. This is useful in cases where "phase markers" using
__xray_customevent(...) can have very few instructions, must never be
instrumented when entered/exited.

Reviewers: rnk, dblaikie, kpw

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D40601

llvm-svn: 319388
2017-11-30 00:04:54 +00:00
..
INPUTS
bindings [python] [tests] Fix test_linkage for unique external linkage 2017-11-11 20:01:41 +00:00
cmake [CMake][Fuchsia] Disable terminfo database in Fuchsia toolchain 2017-11-27 20:29:13 +00:00
docs Add the hasDefinition() AST matcher to match class declarations that also have a definition. 2017-11-29 21:21:51 +00:00
examples
include [XRay][clang] Introduce -fxray-always-emit-customevents 2017-11-30 00:04:54 +00:00
lib [XRay][clang] Introduce -fxray-always-emit-customevents 2017-11-30 00:04:54 +00:00
runtime Allow building libFuzzer tests in two-stage compiler-rt build. 2017-10-13 23:50:53 +00:00
test [XRay][clang] Introduce -fxray-always-emit-customevents 2017-11-30 00:04:54 +00:00
tools [SourceLocations] Use stronger sort predicate to remove non-deterministic ordering 2017-11-29 20:55:13 +00:00
unittests Add the hasDefinition() AST matcher to match class declarations that also have a definition. 2017-11-29 21:21:51 +00:00
utils Determine the attribute subject for diagnostics based on declarative information in DeclNodes.td. This greatly reduces the number of enumerated values used for more complex diagnostics; these are now only required when the "attribute only applies to" diagnostic needs to be generated manually as part of semantic processing. 2017-11-26 20:01:12 +00:00
www Update link to the Chromium Clang page 2017-11-13 23:27:53 +00:00
.arcconfig [clang] Set up .arcconfig to point to new Diffusion C repository 2017-11-27 17:21:24 +00:00
.clang-format
.clang-tidy
.gitignore
CMakeLists.txt [CMake] Support side-by-side checkouts in multi-stage build 2017-11-29 00:34:46 +00:00
CODE_OWNERS.TXT Change code owner for Clang Static Analyzer to Devin Coughlin. 2017-11-17 23:19:04 +00:00
INSTALL.txt
LICENSE.TXT
ModuleInfo.txt
NOTES.txt
README.txt Test commit 2017-10-21 16:03:17 +00:00

README.txt

//===----------------------------------------------------------------------===//
// C Language Family Front-end
//===----------------------------------------------------------------------===//

Welcome to Clang.  This is a compiler front-end for the C family of languages
(C, C++, Objective-C, and Objective-C++) which is built as part of the LLVM
compiler infrastructure project.

Unlike many other compiler frontends, Clang is useful for a number of things
beyond just compiling code: we intend for Clang to be host to a number of
different source-level tools.  One example of this is the Clang Static Analyzer.

If you're interested in more (including how to build Clang) it is best to read
the relevant web sites.  Here are some pointers:

Information on Clang:             http://clang.llvm.org/
Building and using Clang:         http://clang.llvm.org/get_started.html
Clang Static Analyzer:            http://clang-analyzer.llvm.org/
Information on the LLVM project:  http://llvm.org/

If you have questions or comments about Clang, a great place to discuss them is
on the Clang development mailing list:
  http://lists.llvm.org/mailman/listinfo/cfe-dev

If you find a bug in Clang, please file it in the LLVM bug tracker:
  http://llvm.org/bugs/