Skip to content
  1. Jun 22, 2008
  2. May 23, 2008
  3. May 22, 2008
  4. May 13, 2008
  5. May 06, 2008
  6. Jan 29, 2008
  7. Dec 29, 2007
  8. Dec 01, 2007
    • Duncan Sands's avatar
      Integrate the readonly/readnone logic more deeply · 68b6f509
      Duncan Sands authored
      into alias analysis.  This meant updating the API
      which now has versions of the getModRefBehavior,
      doesNotAccessMemory and onlyReadsMemory methods
      which take a callsite parameter.  These should be
      used unless the callsite is not known, since in
      general they can do a better job than the versions
      that take a function.  Also, users should no longer
      call the version of getModRefBehavior that takes
      both a function and a callsite.  To reduce the
      chance of misuse it is now protected.
      
      llvm-svn: 44487
      68b6f509
  9. Nov 26, 2007
  10. Nov 01, 2007
    • Duncan Sands's avatar
      Executive summary: getTypeSize -> getTypeStoreSize / getABITypeSize. · 44b8721d
      Duncan Sands authored
      The meaning of getTypeSize was not clear - clarifying it is important
      now that we have x86 long double and arbitrary precision integers.
      The issue with long double is that it requires 80 bits, and this is
      not a multiple of its alignment.  This gives a primitive type for
      which getTypeSize differed from getABITypeSize.  For arbitrary precision
      integers it is even worse: there is the minimum number of bits needed to
      hold the type (eg: 36 for an i36), the maximum number of bits that will
      be overwriten when storing the type (40 bits for i36) and the ABI size
      (i.e. the storage size rounded up to a multiple of the alignment; 64 bits
      for i36).
      
      This patch removes getTypeSize (not really - it is still there but
      deprecated to allow for a gradual transition).  Instead there is:
      
      (1) getTypeSizeInBits - a number of bits that suffices to hold all
      values of the type.  For a primitive type, this is the minimum number
      of bits.  For an i36 this is 36 bits.  For x86 long double it is 80.
      This corresponds to gcc's TYPE_PRECISION.
      
      (2) getTypeStoreSizeInBits - the maximum number of bits that is
      written when storing the type (or read when reading it).  For an
      i36 this is 40 bits, for an x86 long double it is 80 bits.  This
      is the size alias analysis is interested in (getTypeStoreSize
      returns the number of bytes).  There doesn't seem to be anything
      corresponding to this in gcc.
      
      (3) getABITypeSizeInBits - this is getTypeStoreSizeInBits rounded
      up to a multiple of the alignment.  For an i36 this is 64, for an
      x86 long double this is 96 or 128 depending on the OS.  This is the
      spacing between consecutive elements when you form an array out of
      this type (getABITypeSize returns the number of bytes).  This is
      TYPE_SIZE in gcc.
      
      Since successive elements in a SequentialType (arrays, pointers
      and vectors) need to be aligned, the spacing between them will be
      given by getABITypeSize.  This means that the size of an array
      is the length times the getABITypeSize.  It also means that GEP
      computations need to use getABITypeSize when computing offsets.
      Furthermore, if an alloca allocates several elements at once then
      these too need to be aligned, so the size of the alloca has to be
      the number of elements multiplied by getABITypeSize.  Logically
      speaking this doesn't have to be the case when allocating just
      one element, but it is simpler to also use getABITypeSize in this
      case.  So alloca's and mallocs should use getABITypeSize.  Finally,
      since gcc's only notion of size is that given by getABITypeSize, if
      you want to output assembler etc the same as gcc then getABITypeSize
      is the size you want.
      
      Since a store will overwrite no more than getTypeStoreSize bytes,
      and a read will read no more than that many bytes, this is the
      notion of size appropriate for alias analysis calculations.
      
      In this patch I have corrected all type size uses except some of
      those in ScalarReplAggregates, lib/Codegen, lib/Target (the hard
      cases).  I will get around to auditing these too at some point,
      but I could do with some help.
      
      Finally, I made one change which I think wise but others might
      consider pointless and suboptimal: in an unpacked struct the
      amount of space allocated for a field is now given by the ABI
      size rather than getTypeStoreSize.  I did this because every
      other place that reserves memory for a type (eg: alloca) now
      uses getABITypeSize, and I didn't want to make an exception
      for unpacked structs, i.e. I did it to make things more uniform.
      This only effects structs containing long doubles and arbitrary
      precision integers.  If someone wants to pack these types more
      tightly they can always use a packed struct.
      
      llvm-svn: 43620
      44b8721d
  11. Oct 31, 2007
  12. Oct 03, 2007
  13. Oct 01, 2007
  14. Sep 25, 2007
  15. Sep 24, 2007
  16. Sep 19, 2007
  17. Sep 18, 2007
  18. Aug 21, 2007
  19. Aug 18, 2007
  20. Jul 31, 2007
  21. Jul 30, 2007
  22. Jun 08, 2007
  23. Jun 07, 2007
  24. Jun 05, 2007
  25. Jun 04, 2007
  26. Jun 03, 2007
  27. Jun 02, 2007
  28. May 30, 2007
  29. May 06, 2007
  30. May 03, 2007
  31. May 02, 2007
  32. May 01, 2007
  33. Apr 25, 2007
  34. Apr 24, 2007
  35. Apr 21, 2007
  36. Apr 20, 2007
  37. Apr 18, 2007
  38. Apr 17, 2007
Loading