Parse #define from included files like autoconf.h

[jankapte]

Feature Request

Looks like the extension does not pick up #define or other preprocessor directives from header files:

autoconf.h:

c_cpp_properties.json:

(full config below)
Results in grayed out section:

using "defines": ["CONFIG_ENG"] does work:

I'd prefer not to use the "defines" array, because there are many defines and they change from build config to build config and instead I'd love to parse the defines from the autoconf.h.

Is that possible already or would that be a new feature?

Thanks.

full config:

{
    "configurations": [
        {
            "name": "GCC DevContainer",
            "cStandard": "c17",
            "cppStandard": "gnu++20",
            "compilerPath": "/opt/arm-gnu-toolchain-x86_64-arm-none-eabi/13.3.rel1/bin/arm-none-eabi-gcc",
            "intelliSenseMode": "linux-gcc-arm",
            "compilerArgs": [
                "-mcpu=cortex-m4",
                "-mthumb",
                "-mfloat-abi=hard",
                "-mfpu=fpv4-sp-d16",
                "-mabi=aapcs",
                "-DARM_MATH_CM4",
                "-D__FPU_PRESENT=1",
                "-ffunction-sections",
                "-fdata-sections",
                "-fno-strict-aliasing",
                "-fno-builtin",
                "-fshort-enums",
                "-Wno-unused-function",
                "-fmerge-all-constants",
                "-fomit-frame-pointer",
                "-Og",
                "-fno-unroll-loops",
                "-fno-inline",
                "-fno-code-hoisting",
                "-fno-strict-aliasing",
                "-fno-schedule-insns",
                "-fno-schedule-insns2",
                "-g"
            ],
            // "defines": ["CONFIG_ENG"],
            "forcedInclude": [
                "out/autoconf.h"
            ],
            "mergeConfigurations": true,
            "includePath": [
                "out/"
            ]
        }
    ],
    "version": 4,
    "enableConfigurationSquiggles": true
}

[sean-mcmanus]

@jankapte We do pick up defines from header files and forced include files as long as they're being included in the TU. The relative path out/autoconf.h needs to be absolute via something like ${workspaceFolder}/out/autoconf.h, same with the includePath. You can run C/C++: Log Diagnostics to see how the particular TU is getting configured to see if it's as expected or not.

[Colengms]

Using an absolute path should work, though cpptools should be trying to resolve forcedInclude's against include paths. If the include path is out, the forcedInclude should probably be just autoconf.h, unless it's under out\out\. I think includePath supports relative paths, considering them to be under ${workspaceFolder}, so shouldn't need to be an absolute path.

C/C++: Log Diagnotics output would tell us more. A simple self-contained repro example, in the form of a zip file or GitHub repo, would be the easiest to diagnose.