bd3a1de683
The introduction and some examples are on this page: https://devblogs.microsoft.com/cppblog/announcing-jmc-stepping-in-visual-studio/ The `/JMC` flag enables these instrumentations: - Insert at the beginning of every function immediately after the prologue with a call to `void __fastcall __CheckForDebuggerJustMyCode(unsigned char *JMC_flag)`. The argument for `__CheckForDebuggerJustMyCode` is the address of a boolean global variable (the global variable is initialized to 1) with the name convention `__<hash>_<filename>`. All such global variables are placed in the `.msvcjmc` section. - The `<hash>` part of `__<hash>_<filename>` has a one-to-one mapping with a directory path. MSVC uses some unknown hashing function. Here I used DJB. - Add a dummy/empty COMDAT function `__JustMyCode_Default`. - Add `/alternatename:__CheckForDebuggerJustMyCode=__JustMyCode_Default` link option via ".drectve" section. This is to prevent failure in case `__CheckForDebuggerJustMyCode` is not provided during linking. Implementation: All the instrumentations are implemented in an IR codegen pass. The pass is placed immediately before CodeGenPrepare pass. This is to not interfere with mid-end optimizations and make the instrumentation target-independent (I'm still working on an ELF port in a separate patch). Reviewed By: hans Differential Revision: https://reviews.llvm.org/D118428 |
||
|---|---|---|
| .. | ||
| bindings | ||
| cmake | ||
| docs | ||
| examples | ||
| include | ||
| INPUTS | ||
| lib | ||
| runtime | ||
| test | ||
| tools | ||
| unittests | ||
| utils | ||
| www | ||
| .clang-format | ||
| .clang-tidy | ||
| .gitignore | ||
| CMakeLists.txt | ||
| CODE_OWNERS.TXT | ||
| INSTALL.txt | ||
| LICENSE.TXT | ||
| ModuleInfo.txt | ||
| NOTES.txt | ||
| 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/