Apply defines to struct literal #956
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youknowone
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tests/rust/cfg_field.rs
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| #[repr(C)] | ||
| pub struct Bar { | ||
| pub x: i32, | ||
| #[cfg(windows)] | ||
| pub y: u32, | ||
| } | ||
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| impl Bar { | ||
| pub const BAR: Self = Self { | ||
| x: 0, | ||
| #[cfg(windows)] | ||
| y: 0, | ||
| }; | ||
| } |
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How can I properly add a test? This change doesn't add diff
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I didn't push newline/indent fix not to break test yet. Please let me know if the approach is okay. Then I will finish the whitespace work. |
| // In C++, same order as defined is required. | ||
| let ordered_fields = out.bindings().struct_field_names(path); | ||
| for ordered_key in ordered_fields.iter() { | ||
| let last_i = ordered_fields.len() - 1; |
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Ah, the question didn't get saved. It's basically... can't this underflow? It'd be better to do if ordered_fields.is_empty() { 0 } else { ordered_fields.len() - 1 };
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Ah, it might be harder than that... Recording with a bit whether we have conditional fields, and either skip generating the constant or generate it without the conditions for C seems feasible.
Alternatively doing some macro soup for C might work but it is annoying. Something like gathering the conditional fields first, and generating something like:
#ifdef X11
#define zero_(v) .zero = v,
#else
#define zero_(v)
#endif
#define ConditionalField_ZERO (ConditionalField){ \
zero_(0) \
};
Or so, but that gets clunky.
youknowone
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Thank you for the advice. It had progress, but not yet finished.
I left another comment for duplicated field generation.
Another problem is constexpr context. This is solvedwrite_literal needs context about allow_constexpr to choose macro or inline field. Do you have a suggestion for that?
| if self.config.language == Language::C { | ||
| for ordered_key in ordered_fields.iter() { | ||
| if let Some(lit) = fields.get(ordered_key) { | ||
| if let Some(condition) = lit.cfg.to_condition(self.config) { | ||
| out.new_line(); | ||
| condition.write_before(self.config, out); | ||
| let define = format!("#define __{export_name}_{ordered_key}(v)"); | ||
| write!(out, "{define} (v)"); | ||
| write!(out, "\n#else\n"); | ||
| write!(out, "{define}"); | ||
| condition.write_after(self.config, out); | ||
| } | ||
| } | ||
| } | ||
| } |
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Where is the good place to put this?
From this place, it will write duplicated definitions for each literal definition. That will trigger compiler warnings about redefinition.
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@emilio This part is also not resolved yet
youknowone
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| @@ -911,30 +911,42 @@ impl LanguageBackend for CLikeLanguageBackend<'_> { | |||
| fields, | |||
| path, | |||
| } => { | |||
| let is_constexpr = self.config.language == Language::Cxx | |||
| && (self.config.constant.allow_constexpr || l.can_be_constexpr()); | |||
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This seems wrong? Shouldn't it be allow_constexpr && can_be_constexpr?
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Oh.. I was confused by allow_static_const. Thank you
| if is_constexpr { | ||
| if i > 0 { | ||
| write!(out, ", "); | ||
| } |
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Factor this out of the if/else?
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If you looked in first commit, this is changed in second commit
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If you don't mind, I separated the former 2 commits to another PR in #988, which is not directly related to cfg handling.
| } else { | ||
| write!(out, ".{} = ", ordered_key); | ||
| } | ||
| self.write_literal(out, lit); |
tests/expectations/cfg_both.c
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| #else | ||
| #define __ConditionalField_field(v) | ||
| #endif | ||
| #define ConditionalField_ONE (ConditionalField){ .field = __ConditionalField_field(1) } |
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Does this even build when it's not defined? Doesn't it expand to .field =?
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@emilio could you take another look? |
Fix #955