Fix DWARF void return type confidence #7888
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Previously, functions with missing DW_AT_type (void return) were assigned confidence 0, allowing Binary Ninja's analysis to override them with incorrect inferred types (e.g., uint64_t). Per DWARF spec section 3.3.2, a missing DW_AT_type on a subprogram means void, not "unknown". However, with minimal debug info (-g1), types are omitted entirely, so we can't distinguish void from unknown. This fix: - Uses MAX_CONFIDENCE for explicit return types (was 128), matching parameter confidence for consistency - Uses MAX_CONFIDENCE for void when full debug info is present (detected by checking if any type definitions exist in the compilation unit) - Keeps confidence 0 for minimal debug info (-g1) to allow analysis to infer Tested with C (-g1, -g2) and C++ (-g1, -g2) code to verify correct behavior across debug levels and languages (C uses DW_AT_prototyped, C++ doesn't). Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Previously, functions with missing DW_AT_type (void return) were assigned confidence 0, allowing Binary Ninja's analysis to override them with incorrect inferred types (e.g., uint64_t).
Per DWARF spec section 3.3.2, a missing DW_AT_type on a subprogram means void, not "unknown". However, with minimal debug info (-g1), types are omitted entirely, so we can't distinguish void from unknown.
This fix:
Tested with C (-g1, -g2) and C++ (-g1, -g2) code to verify correct behavior across debug levels and languages (C uses DW_AT_prototyped, C++ doesn't).
Here's the before and after (TL;DR: void applies from dwarf debug info now)
After