components/developer/gcc-13/patches/0006-allow-the-global-disabling-of-function-cloning.patch

   1 From b76e65d545bbf9c3c83e06ccecbe75f34a5ae07a Mon Sep 17 00:00:00 2001
   2 From: Richard Lowe <richlowe@richlowe.net>
   3 Date: Sun, 30 Sep 2012 16:44:14 -0400
   4 Subject: allow the global disabling of function cloning
   5
   6 Optimizations which clone functions to create call-specific implementations
   7 which may be better optimized also dissociate these functions from their
   8 symbol names in ways harmful to tracing and debugging (since there are now
   9 several implementations of a single source symbol, quite possibly none of them
  10 having the actual source symbol name).
  11
  12 This allows any function cloning to be disabled, and makes any such
  13 optimization ineffective, and our source safe for debuggers everywhere.
  14 ---
  15  gcc/attribs.cc      |  9 +++++++++
  16  gcc/common.opt      |  5 +++++
  17  gcc/doc/invoke.texi | 10 ++++++++++
  18  3 files changed, 24 insertions(+)
  19
  20 diff --git a/gcc/attribs.cc b/gcc/attribs.cc
  21 index b1300018d1e8..6f17d96a8327 100644
  22 --- a/gcc/attribs.cc
  23 +++ b/gcc/attribs.cc
  24 @@ -695,6 +695,15 @@ decl_attributes (tree *node, tree attributes, int flags,
  25         attributes = tree_cons (get_identifier ("no_icf"),  NULL, attributes);
  26      }
  27
  28 +  /* If the user passed -fno-clone-functions, all functions should be treated
  29 +     as "noclone" */
  30 +  if (TREE_CODE (*node) == FUNCTION_DECL
  31 +      && !flag_clone_functions)
  32 +    {
  33 +      if (lookup_attribute ("noclone", attributes) == NULL)
  34 +       attributes = tree_cons (get_identifier ("noclone"),  NULL, attributes);
  35 +    }
  36 +
  37    targetm.insert_attributes (*node, &attributes);
  38
  39    /* Note that attributes on the same declaration are not necessarily
  40 diff --git a/gcc/common.opt b/gcc/common.opt
  41 index 73560e307c7a..d5460f4727c2 100644
  42 --- a/gcc/common.opt
  43 +++ b/gcc/common.opt
  44 @@ -1216,6 +1216,11 @@ fcode-hoisting
  45  Common Var(flag_code_hoisting) Optimization
  46  Enable code hoisting.
  47
  48 +fclone-functions
  49 +Common Var(flag_clone_functions) Init(1)
  50 +Allow the compiler to clone functions to facilitate certain optimizations.
  51 +Enabled by default.
  52 +
  53  fcombine-stack-adjustments
  54  Common Var(flag_combine_stack_adjustments) Optimization
  55  Looks for opportunities to reduce stack adjustments and stack references.
  56 diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
  57 index 8bd0a8357d12..cadce96a0f5b 100644
  58 --- a/gcc/doc/invoke.texi
  59 +++ b/gcc/doc/invoke.texi
  60 @@ -535,6 +535,7 @@ Objective-C and Objective-C++ Dialects}.
  61  -fassociative-math  -fauto-profile  -fauto-profile[=@var{path}]
  62  -fauto-inc-dec  -fbranch-probabilities
  63  -fcaller-saves
  64 +-fclone-functions
  65  -fcombine-stack-adjustments  -fconserve-stack
  66  -fcompare-elim  -fcprop-registers  -fcrossjumping
  67  -fcse-follow-jumps  -fcse-skip-blocks  -fcx-fortran-rules
  68 @@ -12777,6 +12778,15 @@ and then tries to find ways to combine them.
  69
  70  Enabled by default at @option{-O1} and higher.
  71
  72 +@opindex fno-clone-functions
  73 +@item -fno-clone-functions
  74 +Forbid the implicit cloning of functions implicit in certain
  75 +optimizations.  This also effectively will disable any optimization
  76 +which wishes to clone functions, equivalent to each function having
  77 +the ``noclone'' attribute.  This allows the prevention of the
  78 +dissociation of a piece of text from an intelligible and expected
  79 +symbol name, which may hamper debugging and tracing.
  80 +
  81  @opindex fipa-ra
  82  @item -fipa-ra
  83  Use caller save registers for allocation if those registers are not used by