F.2 Tracing file format

Every mpatrol tracing output file contains the following components.

• 4 bytes containing the characters `M', `T', `R' and `C'.
• 1 unsigned integer representing the value `1'. This is used by mptrace to determine the endianness of the processor that produced the tracing output file so that it can decide whether to perform byte-swapping on the input data.
• 1 unsigned integer containing the version number of the mpatrol library which produced the tracing output file.
• One or more of the following event records.
  • If the event is a system heap allocation for use by the mpatrol library's internal data structures then the event record will begin with the character `I' followed by the start address and size in bytes of the heap allocation encoded as unsigned LEB128 numbers.
  • If the event is a system heap allocation for use by the program's memory allocations then the event record will begin with the character `H' followed by the start address and size in bytes of the heap allocation encoded as unsigned LEB128 numbers.
  • If the event is a memory allocation then the event record will begin with the character `A' followed by the allocation index, start address and size in bytes of the memory allocation encoded as unsigned LEB128 numbers. From version 1.4.5 of the mpatrol library, the thread identifier, function name, file name and line number are also written out as part of the event record (see below).
  • If the event is a memory reallocation then the event record will begin with the character `R' followed by the allocation index, start address and size of the new memory allocation encoded as an unsigned LEB128 number. From version 1.4.5 of the mpatrol library, the thread identifier, function name, file name and line number are also written out as part of the event record (see below).
  • If the event is a memory deallocation then the event record will begin with the character `F' followed by the allocation index of the memory allocation encoded as an unsigned LEB128 number. From version 1.4.5 of the mpatrol library, the thread identifier, function name, file name and line number are also written out as part of the event record (see below).
• From version 1.4.5 of the mpatrol library, event records contain the following additional information.
  • The thread identifier as an unsigned LEB128 number.
  • The cached source function name. If the first byte is zero then there is no associated function name. If the first byte has the most significant bit set then the following null-terminated string defines a source function name associated with the number in the remaining 7 bits. If the first byte does not have the most significant bit set then it is taken to be the index of a previously defined source function name.
  • The cached source file name. If the first byte is zero then there is no associated file name. If the first byte has the most significant bit set then the following null-terminated string defines a source file name associated with the number in the remaining 7 bits. If the first byte does not have the most significant bit set then it is taken to be the index of a previously defined source file name.
  • The source line number as an unsigned LEB128 number.
• 4 bytes containing the characters `M', `T', `R' and `C'.