components/developer/gcc-7/patches/0006-allow-the-global-disabling-of-function-cloning.patch

   1 From 74e4c60103b72f1e4714db11a6d83b60feb85c4f 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: [PATCH 06/11] 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/common.opt      |  5 +++++
  16  gcc/doc/invoke.texi | 11 ++++++++++-
  17  gcc/tree-inline.c   | 11 ++++++-----
  18  3 files changed, 21 insertions(+), 6 deletions(-)
  19
  20 diff --git a/gcc/common.opt b/gcc/common.opt
  21 index 978fbc83b89..e38dc343afd 100644
  22 --- a/gcc/common.opt
  23 +++ b/gcc/common.opt
  24 @@ -1076,6 +1076,11 @@ fcode-hoisting
  25  Common Report Var(flag_code_hoisting) Optimization
  26  Enable code hoisting.
  27
  28 +fclone-functions
  29 +Common Report Var(flag_clone_functions) Init(1)
  30 +Allow the compiler to clone functions to facilitate certain optimizations.
  31 +Enabled by default.
  32 +
  33  fcombine-stack-adjustments
  34  Common Report Var(flag_combine_stack_adjustments) Optimization
  35  Looks for opportunities to reduce stack adjustments and stack references.
  36 diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
  37 index 68127bbf6ef..4024dd8af67 100644
  38 --- a/gcc/doc/invoke.texi
  39 +++ b/gcc/doc/invoke.texi
  40 @@ -359,7 +359,7 @@ Objective-C and Objective-C++ Dialects}.
  41  -fauto-inc-dec  -fbranch-probabilities @gol
  42  -fbranch-target-load-optimize  -fbranch-target-load-optimize2 @gol
  43  -fbtr-bb-exclusive  -fcaller-saves @gol
  44 --fcombine-stack-adjustments  -fconserve-stack @gol
  45 +-fclone-functions -fcombine-stack-adjustments  -fconserve-stack @gol
  46  -fcompare-elim  -fcprop-registers  -fcrossjumping @gol
  47  -fcse-follow-jumps  -fcse-skip-blocks  -fcx-fortran-rules @gol
  48  -fcx-limited-range @gol
  49 @@ -7977,6 +7977,15 @@ and then tries to find ways to combine them.
  50
  51  Enabled by default at @option{-O1} and higher.
  52
  53 +@item -fno-clone-functions
  54 +@opindex fno-clone-functions
  55 +Forbid the implicit cloning of functions implicit in certain
  56 +optimizations.  This also effectively will disable any optimization
  57 +which wishes to clone functions, equivalent to each function having
  58 +the ``noclone'' attribute.  This allows the prevention of the
  59 +dissociation of a piece of text from an intelligible and expected
  60 +symbol name, which may hamper debugging and tracing.
  61 +
  62  @item -fipa-ra
  63  @opindex fipa-ra
  64  Use caller save registers for allocation if those registers are not used by
  65 diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c
  66 index f56d09e1bdb..5278ece9c74 100644
  67 --- a/gcc/tree-inline.c
  68 +++ b/gcc/tree-inline.c
  69 @@ -659,7 +659,7 @@ remap_decls (tree decls, vec<tree, va_gc> **nonlocalized_list,
  70           gcc_assert (DECL_P (new_var));
  71           DECL_CHAIN (new_var) = new_decls;
  72           new_decls = new_var;
  73 -
  74 +
  75           /* Also copy value-expressions.  */
  76           if (VAR_P (new_var) && DECL_HAS_VALUE_EXPR_P (new_var))
  77             {
  78 @@ -3489,7 +3489,7 @@ declare_return_variable (copy_body_data *id, tree return_slot, tree modify_dest,
  79   done:
  80    /* Register the VAR_DECL as the equivalent for the RESULT_DECL; that
  81       way, when the RESULT_DECL is encountered, it will be
  82 -     automatically replaced by the VAR_DECL.
  83 +     automatically replaced by the VAR_DECL.
  84
  85       When returning by reference, ensure that RESULT_DECL remaps to
  86       gimple_val.  */
  87 @@ -4586,7 +4586,7 @@ expand_call_inline (basic_block bb, gimple *stmt, copy_body_data *id)
  88      {
  89        id->block = make_node (BLOCK);
  90        BLOCK_ABSTRACT_ORIGIN (id->block) = fn;
  91 -      BLOCK_SOURCE_LOCATION (id->block)
  92 +      BLOCK_SOURCE_LOCATION (id->block)
  93         = LOCATION_LOCUS (gimple_location (stmt));
  94        prepend_lexical_block (gimple_block (stmt), id->block);
  95      }
  96 @@ -5714,7 +5714,8 @@ bool
  97  tree_versionable_function_p (tree fndecl)
  98  {
  99    return (!lookup_attribute ("noclone", DECL_ATTRIBUTES (fndecl))
 100 -         && copy_forbidden (DECL_STRUCT_FUNCTION (fndecl)) == NULL);
 101 +      && (copy_forbidden (DECL_STRUCT_FUNCTION (fndecl)) == NULL)
 102 +         && flag_clone_functions);
 103  }
 104
 105  /* Delete all unreachable basic blocks and update callgraph.
 106 @@ -5833,7 +5834,7 @@ update_clone_info (copy_body_data * id)
 107     tree with another tree while duplicating the function's
 108     body, TREE_MAP represents the mapping between these
 109     trees. If UPDATE_CLONES is set, the call_stmt fields
 110 -   of edges of clones of the function will be updated.
 111 +   of edges of clones of the function will be updated.
 112
 113     If non-NULL ARGS_TO_SKIP determine function parameters to remove
 114     from new version.
 115 --
 116 2.15.0
 117