Add extra checks to select the right mapping and filter samples within it. #266
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* Pass pointers to the perf profile proto and the main memory mapping instead of storing them as class members. * The `PerfParser` also does not need to be held on to - it is used only once. * The `PerfReader` must be held on to since it owns all of the perf related data.
| // Memory mapping protection flag bits on Linux, from `sys/mman.h`. | ||
| constexpr int kProtRead = 0b001; /* PROT_READ */ | ||
| constexpr int kProtWrite = 0b010; /* PROT_WRITE */ | ||
| constexpr int kProtExec = 0b100; /* PROT_EXEC */ |
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Can we use PROT_READ, PROT_WRITE, and PROT_EXEC directly in our code?
Normally, they should be provided by sys/mman.h - and if they are, I'd go for the system definitions rather than define our own.
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They are indeed provided by sys/mman.h, but I opted to define them here with the comment pointing to sys/mman.h so that it doesn't stop this from being built on Windows. I could use a __has_include(<sys/mman.h>) with a preprocessor macro at the top to use sys/mman.h whenever possible and just define PROT_{READ,WRITE,EXEC} otherwise. Or would simply dropping Windows compatibility make more sense?
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We already have a Linux-only (POSIX maybe) dependency with finding accessed addresses, so I'm not too worried about that.
But we could do the __has_include check and include it if defined, otherwise take our own definitions.
…bject. * A new check of the sample PID against the main mapping PID. * Remove the check for whether the block's code was within the bounds of the executable segment in terms of file addresses, this is redundant as long as the mapping is valid.
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of the executable segment in terms of file addresses, this is
redundant as long as the mapping is valid.