Update FAQ: -resource-dir is no longer recorded

Fangrui Song 2018-12-26 17:46:01 -08:00
parent 2a16b9c89d
commit 021bf49869

62
FAQ.md

@ -33,10 +33,6 @@ For CMake this can be achieved in a single line: `target_include_directories(<ta
Check `Clang_EXECUTABLE` in your `CMakeCache.txt`. The output of command `$Clang_EXECUTABLE -print-resource-dir` will be passed to `-DDEFAULT_RESOURCE_DIRECTORY`. Make sure you can locate `include/stddef.h` in the resource directory.
Read [[Initialization options]] how to set `"cacheFormat": "json"`.
If `"cacheDirectory": "/tmp/ccls"`, and the source file is `/tmp/c/a.cc`,
run `jq . < /tmp/ccls/@tmp@c/a.cc.json` to see if `-resource-dir` is correct, e.g. `"-resource-dir=/home/ray/ccls/Debug/lib/clang+llvm-6.0.0-x86_64-linux-gnu-ubuntu-16.04/lib/clang/6.0.0"`
#### `-isystem`
ccls infers system search paths (e.g. `/usr/include`). The underneath mechanism is similar to that of `clang -v -E -x c++ /dev/null`.
@ -54,6 +50,13 @@ If you want to specify additional search paths:
* `print '%clang\n%cpp -std=gnu++17\n-isystem/tmp/include' > .ccls`
* emacs-ccls: `(setq ccls-extra-init-params '(:clang (:extraArgs ["-isystem" "/tmp/include"])))`
### Inspect index files
Read [[Initialization options]] how to set `"cacheFormat": "json"`.
If `"cacheDirectory": "/tmp/ccls"`, and the source file is `/tmp/c/a.cc`,
run `jq . < /tmp/ccls/@tmp@c/a.cc.json`
### Project root detection
[emacs-ccls](https://github.com/MaskRay/emacs-cquery/) locates the project root in the following order:
@ -88,57 +91,6 @@ ulimit -n 32768
* soft nofile 32768
```
### Includes
Here is an example.
`include/a.h`:
```c
int bad;
```
`a.cc`:
```c
int main(){return bad;}
```
`.ccls`:
```text
%clang
%cpp -std=gnu++14
-Iinclude
```
ccls will save a file in `cacheDirectory`:
`jq . < /tmp/ccls/@tmp@c/a.cc.json`
```json
15
{
"last_modification_time": 1520737513,
"language": 1,
"import_file": "/tmp/c/a.cc",
"args": [
"clang++",
"-working-directory=/tmp/c",
"-std=gnu++14",
"-Iinclude",
"/tmp/c/a.cc",
"-resource-dir=/home/maskray/Dev/Util/ccls/build/debug/lib/clang+llvm-6.0.0-x86_64-linux-gnu-ubuntu-14.04/lib/clang/6.0.0",
"-Wno-unknown-warning-option",
"-fparse-all-comments"
],
"includes": [
{
"line": 0,
"resolved_path": "/tmp/c/include/a.h"
}
],
"dependencies": [
"/tmp/c/include/a.h"
],
...
```
### Diagnostics in headers
For efficiency, headers are compiled on their own (as if `clang [options] a.h`) to utilize Clang's preamble optimization.