llvm-project

8c0f3b6e - [BOLT] Fix debug line emission for functions in multiple compilation units (#151230)

[BOLT] Fix debug line emission for functions in multiple compilation units (#151230) This patch fixes a bug in BOLT's debug line emission where functions that belong to multiple compilation units (such as inline functions in header files) were not handled correctly. Previously, BOLT incorrectly assumed that a binary function could belong to only one compilation unit, leading to incomplete or incorrect debug line information. ### **Problem** When a function appears in multiple compilation units (common scenarios include): * Template instantiated functions * Inline functions defined in header files included by multiple source files BOLT would only emit debug line information for one compilation unit, losing debug information for other CUs where the function was compiled. This resulted in incomplete debugging information and could cause debuggers to fail to set breakpoints or show incorrect source locations. ### **Root Cause** The issue was in BOLT's assumption that each binary function maps to exactly one compilation unit. However, when the same function (e.g., an inline function from a header) is compiled into multiple object files, it legitimately belongs to multiple CUs in the final binary.