components/developer/gcc-14/patches/0004-Implement-fstrict-calling-conventions.patch

   1 From c062e719116039f8c339d70aae4fc7d3b4c3be6b Mon Sep 17 00:00:00 2001
   2 From: Richard Lowe <richlowe@richlowe.net>
   3 Date: Sat, 27 Oct 2012 02:44:09 +0100
   4 Subject: Implement -fstrict-calling-conventions
   5
   6 Stock GCC is overly willing to violate the ABI when calling local functions,
   7 such that it passes arguments in registers on i386.  This hampers debugging
   8 with anything other than a fully-aware DWARF debugger, and is generally not
   9 something we desire.
  10
  11 Implement a flag which disables this behaviour, enabled by default.  The flag is
  12 global, though only effective on i386, to more easily allow its globalization
  13 later which, given the odds, is likely to be necessary.
  14 ---
  15  gcc/common.opt                            |  4 ++++
  16  gcc/config/i386/i386.cc                   |  2 ++
  17  gcc/doc/invoke.texi                       |  6 ++++++
  18  gcc/testsuite/gcc.target/i386/local.c     |  3 ++-
  19  gcc/testsuite/gcc.target/i386/strict-cc.c | 24 +++++++++++++++++++++++
  20  5 files changed, 38 insertions(+), 1 deletion(-)
  21  create mode 100644 gcc/testsuite/gcc.target/i386/strict-cc.c
  22
  23 diff --git a/gcc/common.opt b/gcc/common.opt
  24 index ad3488447752..a4a04b0aa81d 100644
  25 --- a/gcc/common.opt
  26 +++ b/gcc/common.opt
  27 @@ -2931,6 +2931,10 @@ fstrict-aliasing
  28  Common Var(flag_strict_aliasing) Optimization
  29  Assume strict aliasing rules apply.
  30
  31 +fstrict-calling-conventions
  32 +Common Var(flag_strict_calling_conventions) Init(1)
  33 +Use strict ABI calling conventions even for static functions
  34 +
  35  fstrict-overflow
  36  Common
  37  Treat signed overflow as undefined.  Negated as -fwrapv -fwrapv-pointer.
  38 diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
  39 index 4d6b2b98761d..e0dc5da88b0b 100644
  40 --- a/gcc/config/i386/i386.cc
  41 +++ b/gcc/config/i386/i386.cc
  42 @@ -1207,6 +1207,7 @@ ix86_function_regparm (const_tree type, const_tree decl)
  43          and callee not, or vice versa.  Instead look at whether the callee
  44          is optimized or not.  */
  45        if (target && opt_for_fn (target->decl, optimize)
  46 +         && !flag_strict_calling_conventions
  47           && !(profile_flag && !flag_fentry))
  48         {
  49           if (target->local && target->can_change_signature)
  50 @@ -1303,6 +1304,7 @@ ix86_function_sseregparm (const_tree type, const_tree decl, bool warn)
  51        /* TARGET_SSE_MATH */
  52        && (target_opts_for_fn (target->decl)->x_ix86_fpmath & FPMATH_SSE)
  53        && opt_for_fn (target->decl, optimize)
  54 +      && !flag_strict_calling_conventions
  55        && !(profile_flag && !flag_fentry))
  56      {
  57        if (target->local && target->can_change_signature)
  58 diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
  59 index 9456ced468af..e28412fb4488 100644
  60 --- a/gcc/doc/invoke.texi
  61 +++ b/gcc/doc/invoke.texi
  62 @@ -8036,6 +8036,12 @@ with multiple statement cases using flow-sensitive points-to information.
  63  Only warns when the converted pointer is dereferenced.
  64  Does not warn about incomplete types.
  65
  66 +@opindex fstrict-calling-conventions
  67 +@item -fstrict-calling-conventions
  68 +Use strict ABI calling conventions even with local functions.
  69 +This disable certain optimizations that may cause GCC to call local
  70 +functions in a manner other than that described by the ABI.
  71 +
  72  @opindex Wstrict-overflow
  73  @opindex Wno-strict-overflow
  74  @item -Wstrict-overflow
  75 diff --git a/gcc/testsuite/gcc.target/i386/local.c b/gcc/testsuite/gcc.target/i386/local.c
  76 index f4444951e123..3a487583d81f 100644
  77 --- a/gcc/testsuite/gcc.target/i386/local.c
  78 +++ b/gcc/testsuite/gcc.target/i386/local.c
  79 @@ -1,5 +1,6 @@
  80  /* { dg-do compile } */
  81 -/* { dg-options "-O2 -funit-at-a-time" } */
  82 +/* { dg-options "-O2 -funit-at-a-time -fno-strict-calling-conventions" { target ia32 } } */
  83 +/* { dg-options "-O2 -funit-at-a-time" { target lp64 } } */
  84  /* { dg-final { scan-assembler "magic\[^\\n\]*eax" { target ia32 } } } */
  85  /* { dg-final { scan-assembler "magic\[^\\n\]*(edi|ecx)" { target { ! ia32 } } } } */
  86
  87 diff --git a/gcc/testsuite/gcc.target/i386/strict-cc.c b/gcc/testsuite/gcc.target/i386/strict-cc.c
  88 new file mode 100644
  89 index 000000000000..fa0543e52ff6
  90 --- /dev/null
  91 +++ b/gcc/testsuite/gcc.target/i386/strict-cc.c
  92 @@ -0,0 +1,24 @@
  93 +/* { dg-do compile { target { ilp32 } } } */
  94 +/* { dg-options "-O2 -funit-at-a-time -fstrict-calling-conventions"  } */
  95 +/* { dg-final { scan-assembler "pushl.*\\\$1" } } */
  96 +/* { dg-final { scan-assembler "pushl.*\\\$2" } } */
  97 +/* { dg-final { scan-assembler "pushl.*\\\$3" } } */
  98 +/* { dg-final { scan-assembler "pushl.*\\\$4" } } */
  99 +/* { dg-final { scan-assembler "pushl.*\\\$5" } } */
 100 +
 101 +#include <stdio.h>
 102 +
 103 +/* Verify that local calling convention is not used if strict conventions.  */
 104 +static int t(int, int, int, int, int) __attribute__ ((noinline));
 105 +
 106 +int
 107 +m()
 108 +{
 109 +    t(1, 2, 3, 4, 5);
 110 +}
 111 +
 112 +static int
 113 +t(int a, int b, int c, int d, int e)
 114 +{
 115 +    printf("%d\n", a, b, c, d, e);
 116 +}