On Friday 2006-12-01 Fabian Cenedese wrote: > ... But when I tried it > it didn't mix the lines, I just got (almost) all lines from the cpp > source file and after that the assembler code. I have seen this effect quite regularly. I do not know this for a fact but have always assumed that the incorporation of source code into the assembly listing was a classic stream merge based on line numbers. This works okay as long as the generated code closely parallels the source. It also depends on what bits of intermediate representation are allowed to claim source line correspondence. The reason that I suggest this explanation is that the gcc behavior seems very reminiscent of what I used to see for a while from the Apollo compilers. A classic example was an assignment within a loop with an invariant RHS. If the RHS required any expression evaluation and if the instructions carrying out that evaluation was moved out of the loop then all loop source lines up to and including that assignment would be emitted ahead of the loop in the vicinity of the RHS evaluation. I am writing from rather foggy memories but I believe that the fix was to mark instructions with both a putative line number and a boolean flag indicating whether or not the instruction corresponded to a significant source side-effect. The listing format included a source line number as an end-of-line comment. Thus a motioned expression could still be traced back to a source line. Source lines were merged into the assembly file using the classic scheme alluded to above with the following refinement. When an assembly instruction included a source line correlation higher than the most recently merged source line that line number correlation was ignored unless either a) that instruction was flagged as a significant side-effect or b) there was an uninterrupted run of instructions with that same line number correlation ultimately leading to an instruction that was flagged as a significant side-effect. As I recall the motivation for making these changes was not more readable assembly listing but a need for saner information in the debugger's pc correlation table. /john
