You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
163 lines
8.1 KiB
HTML
163 lines
8.1 KiB
HTML
<html lang="en">
|
|
<head>
|
|
<title>Stack Checking - GNU Compiler Collection (GCC) Internals</title>
|
|
<meta http-equiv="Content-Type" content="text/html">
|
|
<meta name="description" content="GNU Compiler Collection (GCC) Internals">
|
|
<meta name="generator" content="makeinfo 4.13">
|
|
<link title="Top" rel="start" href="index.html#Top">
|
|
<link rel="up" href="Stack-and-Calling.html#Stack-and-Calling" title="Stack and Calling">
|
|
<link rel="prev" href="Exception-Handling.html#Exception-Handling" title="Exception Handling">
|
|
<link rel="next" href="Frame-Registers.html#Frame-Registers" title="Frame Registers">
|
|
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
|
|
<!--
|
|
Copyright (C) 1988-2015 Free Software Foundation, Inc.
|
|
|
|
Permission is granted to copy, distribute and/or modify this document
|
|
under the terms of the GNU Free Documentation License, Version 1.3 or
|
|
any later version published by the Free Software Foundation; with the
|
|
Invariant Sections being ``Funding Free Software'', the Front-Cover
|
|
Texts being (a) (see below), and with the Back-Cover Texts being (b)
|
|
(see below). A copy of the license is included in the section entitled
|
|
``GNU Free Documentation License''.
|
|
|
|
(a) The FSF's Front-Cover Text is:
|
|
|
|
A GNU Manual
|
|
|
|
(b) The FSF's Back-Cover Text is:
|
|
|
|
You have freedom to copy and modify this GNU Manual, like GNU
|
|
software. Copies published by the Free Software Foundation raise
|
|
funds for GNU development.-->
|
|
<meta http-equiv="Content-Style-Type" content="text/css">
|
|
<style type="text/css"><!--
|
|
pre.display { font-family:inherit }
|
|
pre.format { font-family:inherit }
|
|
pre.smalldisplay { font-family:inherit; font-size:smaller }
|
|
pre.smallformat { font-family:inherit; font-size:smaller }
|
|
pre.smallexample { font-size:smaller }
|
|
pre.smalllisp { font-size:smaller }
|
|
span.sc { font-variant:small-caps }
|
|
span.roman { font-family:serif; font-weight:normal; }
|
|
span.sansserif { font-family:sans-serif; font-weight:normal; }
|
|
--></style>
|
|
</head>
|
|
<body>
|
|
<div class="node">
|
|
<a name="Stack-Checking"></a>
|
|
<p>
|
|
Next: <a rel="next" accesskey="n" href="Frame-Registers.html#Frame-Registers">Frame Registers</a>,
|
|
Previous: <a rel="previous" accesskey="p" href="Exception-Handling.html#Exception-Handling">Exception Handling</a>,
|
|
Up: <a rel="up" accesskey="u" href="Stack-and-Calling.html#Stack-and-Calling">Stack and Calling</a>
|
|
<hr>
|
|
</div>
|
|
|
|
<h4 class="subsection">17.9.3 Specifying How Stack Checking is Done</h4>
|
|
|
|
<p>GCC will check that stack references are within the boundaries of the
|
|
stack, if the option <samp><span class="option">-fstack-check</span></samp> is specified, in one of
|
|
three ways:
|
|
|
|
<ol type=1 start=1>
|
|
<li>If the value of the <code>STACK_CHECK_BUILTIN</code> macro is nonzero, GCC
|
|
will assume that you have arranged for full stack checking to be done
|
|
at appropriate places in the configuration files. GCC will not do
|
|
other special processing.
|
|
|
|
<li>If <code>STACK_CHECK_BUILTIN</code> is zero and the value of the
|
|
<code>STACK_CHECK_STATIC_BUILTIN</code> macro is nonzero, GCC will assume
|
|
that you have arranged for static stack checking (checking of the
|
|
static stack frame of functions) to be done at appropriate places
|
|
in the configuration files. GCC will only emit code to do dynamic
|
|
stack checking (checking on dynamic stack allocations) using the third
|
|
approach below.
|
|
|
|
<li>If neither of the above are true, GCC will generate code to periodically
|
|
“probe” the stack pointer using the values of the macros defined below.
|
|
</ol>
|
|
|
|
<p>If neither STACK_CHECK_BUILTIN nor STACK_CHECK_STATIC_BUILTIN is defined,
|
|
GCC will change its allocation strategy for large objects if the option
|
|
<samp><span class="option">-fstack-check</span></samp> is specified: they will always be allocated
|
|
dynamically if their size exceeds <code>STACK_CHECK_MAX_VAR_SIZE</code> bytes.
|
|
|
|
<div class="defun">
|
|
— Macro: <b>STACK_CHECK_BUILTIN</b><var><a name="index-STACK_005fCHECK_005fBUILTIN-4179"></a></var><br>
|
|
<blockquote><p>A nonzero value if stack checking is done by the configuration files in a
|
|
machine-dependent manner. You should define this macro if stack checking
|
|
is required by the ABI of your machine or if you would like to do stack
|
|
checking in some more efficient way than the generic approach. The default
|
|
value of this macro is zero.
|
|
</p></blockquote></div>
|
|
|
|
<div class="defun">
|
|
— Macro: <b>STACK_CHECK_STATIC_BUILTIN</b><var><a name="index-STACK_005fCHECK_005fSTATIC_005fBUILTIN-4180"></a></var><br>
|
|
<blockquote><p>A nonzero value if static stack checking is done by the configuration files
|
|
in a machine-dependent manner. You should define this macro if you would
|
|
like to do static stack checking in some more efficient way than the generic
|
|
approach. The default value of this macro is zero.
|
|
</p></blockquote></div>
|
|
|
|
<div class="defun">
|
|
— Macro: <b>STACK_CHECK_PROBE_INTERVAL_EXP</b><var><a name="index-STACK_005fCHECK_005fPROBE_005fINTERVAL_005fEXP-4181"></a></var><br>
|
|
<blockquote><p>An integer specifying the interval at which GCC must generate stack probe
|
|
instructions, defined as 2 raised to this integer. You will normally
|
|
define this macro so that the interval be no larger than the size of
|
|
the “guard pages” at the end of a stack area. The default value
|
|
of 12 (4096-byte interval) is suitable for most systems.
|
|
</p></blockquote></div>
|
|
|
|
<div class="defun">
|
|
— Macro: <b>STACK_CHECK_MOVING_SP</b><var><a name="index-STACK_005fCHECK_005fMOVING_005fSP-4182"></a></var><br>
|
|
<blockquote><p>An integer which is nonzero if GCC should move the stack pointer page by page
|
|
when doing probes. This can be necessary on systems where the stack pointer
|
|
contains the bottom address of the memory area accessible to the executing
|
|
thread at any point in time. In this situation an alternate signal stack
|
|
is required in order to be able to recover from a stack overflow. The
|
|
default value of this macro is zero.
|
|
</p></blockquote></div>
|
|
|
|
<div class="defun">
|
|
— Macro: <b>STACK_CHECK_PROTECT</b><var><a name="index-STACK_005fCHECK_005fPROTECT-4183"></a></var><br>
|
|
<blockquote><p>The number of bytes of stack needed to recover from a stack overflow, for
|
|
languages where such a recovery is supported. The default value of 75 words
|
|
with the <code>setjmp</code>/<code>longjmp</code>-based exception handling mechanism and
|
|
8192 bytes with other exception handling mechanisms should be adequate for
|
|
most machines.
|
|
</p></blockquote></div>
|
|
|
|
<p>The following macros are relevant only if neither STACK_CHECK_BUILTIN
|
|
nor STACK_CHECK_STATIC_BUILTIN is defined; you can omit them altogether
|
|
in the opposite case.
|
|
|
|
<div class="defun">
|
|
— Macro: <b>STACK_CHECK_MAX_FRAME_SIZE</b><var><a name="index-STACK_005fCHECK_005fMAX_005fFRAME_005fSIZE-4184"></a></var><br>
|
|
<blockquote><p>The maximum size of a stack frame, in bytes. GCC will generate probe
|
|
instructions in non-leaf functions to ensure at least this many bytes of
|
|
stack are available. If a stack frame is larger than this size, stack
|
|
checking will not be reliable and GCC will issue a warning. The
|
|
default is chosen so that GCC only generates one instruction on most
|
|
systems. You should normally not change the default value of this macro.
|
|
</p></blockquote></div>
|
|
|
|
<div class="defun">
|
|
— Macro: <b>STACK_CHECK_FIXED_FRAME_SIZE</b><var><a name="index-STACK_005fCHECK_005fFIXED_005fFRAME_005fSIZE-4185"></a></var><br>
|
|
<blockquote><p>GCC uses this value to generate the above warning message. It
|
|
represents the amount of fixed frame used by a function, not including
|
|
space for any callee-saved registers, temporaries and user variables.
|
|
You need only specify an upper bound for this amount and will normally
|
|
use the default of four words.
|
|
</p></blockquote></div>
|
|
|
|
<div class="defun">
|
|
— Macro: <b>STACK_CHECK_MAX_VAR_SIZE</b><var><a name="index-STACK_005fCHECK_005fMAX_005fVAR_005fSIZE-4186"></a></var><br>
|
|
<blockquote><p>The maximum size, in bytes, of an object that GCC will place in the
|
|
fixed area of the stack frame when the user specifies
|
|
<samp><span class="option">-fstack-check</span></samp>.
|
|
GCC computed the default from the values of the above macros and you will
|
|
normally not need to override that default.
|
|
</p></blockquote></div>
|
|
|
|
</body></html>
|
|
|