Parser: fix for struct compound literal initialization (#299) #302
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Investigated the bug where compound literals like
(struct point){10, 20, 30} produced shifted field values
(e.g., x got garbage, y=10, z=20). Added a temporary fix
by adjusting the source address +4 bytes in parser.c.
Tested with simple cases: x=10, y=20, z=30. This is an
experimental patch; needs review for design correctness.
Refs: sysprog21#299
jserv
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Sep 28, 2025
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visitorckw
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Sep 28, 2025
visitorckw
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Sep 28, 2025
jserv
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DrXiao
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Sep 28, 2025
Previously, array compound literals such as (int[]){100, 200, 300}
failed with an "Unexpected token" error. Struct compound literals
worked correctly, but array syntax [] was unhandled in the parser.
This change adds proper array compound literal handling, including
scalar and pointer contexts. In scalar context, the literal returns
its first element (e.g. int x = (int[]){100,200}; yields 100). In
pointer context, it allocates and initializes backing storage and
returns the address (e.g. int *p = (int[]){100,200};). Arithmetic
expressions using literals (e.g. 50 + (int[]){100}) also evaluate
correctly.
Additional fixes include:
- Consume missing '{' token for int/char compound literals
- Add return statements to prevent control flow fall-through
- Prevent segfaults in pointer assignments by allocating memory
As a result, shecc now supports array compound literals alongside
existing struct compound literals, improving C99 compatibility and
preserving self-hosting capability.
Known limitations remain: designated initializers and complex
expression combinations are still unsupported.
jserv
reviewed
Sep 30, 2025
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This PR is a work-in-progress for issue #299.
adjusting the source address by +4 bytes in parser.c.
Refs: #299
Summary by cubic
Fix struct compound literal initialization in the parser so fields are assigned correctly instead of being shifted. Adds explicit brace-initializer emission and corrects assignment handling, addressing issue #299.