conditional typedef not detected

[johnnychen94]

I'm currently working on a JpegTurbo wrapper, I'm not familiar with C/C++ so I don't know how to describe this question. This is the MWE that I get

❯ cat include/a.h
#define BITS_IN_JSAMPLE 8

❯ cat include/b.h
#if BITS_IN_JSAMPLE == 8
typedef unsigned char JSAMPLE;
#endif

❯ cat include/c.h
#include "a.h"
#include "b.h"
typedef JSAMPLE *JSAMPROW;

using Clang.Generators

headers = joinpath.("include", readdir("include/"))
args = get_default_args()
ctx = create_context(headers, args)
build!(ctx)

With this setup I get:

[ Info: Parsing headers...
[ Info: Processing header: include/a.h
[ Info: Processing header: include/b.h
[ Info: Processing header: include/c.h
[ Info: Building the DAG...
ERROR: LoadError: There is no definition for JSAMPROW's underlying type: [``] at include/c.h:6:18
Stacktrace:
 [1] error(s::String)
   @ Base ./error.jl:33
 [2] resolve_dependency!(dag::ExprDAG, node::ExprNode{Clang.Generators.TypedefDefault, Clang.CLTypedefDecl}, options::Dict{Any, Any})
   @ Clang.Generators ~/.julia/packages/Clang/UrFxU/src/generator/resolve_deps.jl:121
 [3] (::ResolveDependency)(dag::ExprDAG, options::Dict{Any, Any})
   @ Clang.Generators ~/.julia/packages/Clang/UrFxU/src/generator/passes.jl:274
 [4] build!(ctx::Context, stage::Clang.Generators.BuildStage)
   @ Clang.Generators ~/.julia/packages/Clang/UrFxU/src/generator/context.jl:169
 [5] build!(ctx::Context)
   @ Clang.Generators ~/.julia/packages/Clang/UrFxU/src/generator/context.jl:160
 [6] top-level scope
   @ ~/Documents/Julia/JpegTurbo/gen_debug/demo.jl:6
 [7] include(fname::String)
   @ Base.MainInclude ./client.jl:451
 [8] top-level scope
   @ REPL[74]:1

Any guidance would be appreciated.

[johnnychen94]

It seems like I should do

- headers = joinpath.("include", readdir("include/"))
+ headers = ["include/c.h"]

julia> build!(ctx)
[ Info: Processing header: include/c.h
[ Info: Building the DAG...
┌ Warning: default libname: ":libxxx" is being used, did you forget to set `library_name` in the toml file?
└ @ Clang.Generators ~/.julia/packages/Clang/UrFxU/src/generator/audit.jl:16
[ Info: Emit Julia expressions...
const JSAMPLE = Cuchar

const JSAMPROW = Ptr{JSAMPLE}

[ Info: Done!
Context(...)

but TBH I have no idea why it should work like this.

[Gnimuc]

Basically, you only need to include the topmost header. If you include all three headers, Clang.jl will try to parse them all and create three translation units and things may go wrong when doing the CTU analysis(To be clear, we're doing CTU analysis on our own so it's buggy. In the future, we may switch to Clang's CTU module by using ClangCompiler.jl).

The include path should be populated in args, for example, push!(args, "-I/User/xxx/path/to/the/include/folder").

As you put all of those three files into one directory which is one of those default include-paths searched by Clang, you got things to work without adding the include in args.