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.
211 lines
11 KiB
HTML
211 lines
11 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<!-- Copyright (C) 1988-2018 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. -->
|
|
<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
|
|
<head>
|
|
<title>Named Address Spaces (GNU Compiler Collection (GCC) Internals)</title>
|
|
|
|
<meta name="description" content="Named Address Spaces (GNU Compiler Collection (GCC) Internals)">
|
|
<meta name="keywords" content="Named Address Spaces (GNU Compiler Collection (GCC) Internals)">
|
|
<meta name="resource-type" content="document">
|
|
<meta name="distribution" content="global">
|
|
<meta name="Generator" content="makeinfo">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
|
<link href="index.html#Top" rel="start" title="Top">
|
|
<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
|
<link href="Target-Macros.html#Target-Macros" rel="up" title="Target Macros">
|
|
<link href="Misc.html#Misc" rel="next" title="Misc">
|
|
<link href="C_002b_002b-ABI.html#C_002b_002b-ABI" rel="prev" title="C++ ABI">
|
|
<style type="text/css">
|
|
<!--
|
|
a.summary-letter {text-decoration: none}
|
|
blockquote.indentedblock {margin-right: 0em}
|
|
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
|
|
blockquote.smallquotation {font-size: smaller}
|
|
div.display {margin-left: 3.2em}
|
|
div.example {margin-left: 3.2em}
|
|
div.lisp {margin-left: 3.2em}
|
|
div.smalldisplay {margin-left: 3.2em}
|
|
div.smallexample {margin-left: 3.2em}
|
|
div.smalllisp {margin-left: 3.2em}
|
|
kbd {font-style: oblique}
|
|
pre.display {font-family: inherit}
|
|
pre.format {font-family: inherit}
|
|
pre.menu-comment {font-family: serif}
|
|
pre.menu-preformatted {font-family: serif}
|
|
pre.smalldisplay {font-family: inherit; font-size: smaller}
|
|
pre.smallexample {font-size: smaller}
|
|
pre.smallformat {font-family: inherit; font-size: smaller}
|
|
pre.smalllisp {font-size: smaller}
|
|
span.nolinebreak {white-space: nowrap}
|
|
span.roman {font-family: initial; font-weight: normal}
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
|
ul.no-bullet {list-style: none}
|
|
-->
|
|
</style>
|
|
|
|
|
|
</head>
|
|
|
|
<body lang="en">
|
|
<a name="Named-Address-Spaces"></a>
|
|
<div class="header">
|
|
<p>
|
|
Next: <a href="Misc.html#Misc" accesskey="n" rel="next">Misc</a>, Previous: <a href="C_002b_002b-ABI.html#C_002b_002b-ABI" accesskey="p" rel="prev">C++ ABI</a>, Up: <a href="Target-Macros.html#Target-Macros" accesskey="u" rel="up">Target Macros</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
|
|
</div>
|
|
<hr>
|
|
<a name="Adding-support-for-named-address-spaces"></a>
|
|
<h3 class="section">18.29 Adding support for named address spaces</h3>
|
|
<a name="index-named-address-spaces"></a>
|
|
|
|
<p>The draft technical report of the ISO/IEC JTC1 S22 WG14 N1275
|
|
standards committee, <cite>Programming Languages - C - Extensions to
|
|
support embedded processors</cite>, specifies a syntax for embedded
|
|
processors to specify alternate address spaces. You can configure a
|
|
GCC port to support section 5.1 of the draft report to add support for
|
|
address spaces other than the default address space. These address
|
|
spaces are new keywords that are similar to the <code>volatile</code> and
|
|
<code>const</code> type attributes.
|
|
</p>
|
|
<p>Pointers to named address spaces can have a different size than
|
|
pointers to the generic address space.
|
|
</p>
|
|
<p>For example, the SPU port uses the <code>__ea</code> address space to refer
|
|
to memory in the host processor, rather than memory local to the SPU
|
|
processor. Access to memory in the <code>__ea</code> address space involves
|
|
issuing DMA operations to move data between the host processor and the
|
|
local processor memory address space. Pointers in the <code>__ea</code>
|
|
address space are either 32 bits or 64 bits based on the
|
|
<samp>-mea32</samp> or <samp>-mea64</samp> switches (native SPU pointers are
|
|
always 32 bits).
|
|
</p>
|
|
<p>Internally, address spaces are represented as a small integer in the
|
|
range 0 to 15 with address space 0 being reserved for the generic
|
|
address space.
|
|
</p>
|
|
<p>To register a named address space qualifier keyword with the C front end,
|
|
the target may call the <code>c_register_addr_space</code> routine. For example,
|
|
the SPU port uses the following to declare <code>__ea</code> as the keyword for
|
|
named address space #1:
|
|
</p><div class="smallexample">
|
|
<pre class="smallexample">#define ADDR_SPACE_EA 1
|
|
c_register_addr_space ("__ea", ADDR_SPACE_EA);
|
|
</pre></div>
|
|
|
|
<dl>
|
|
<dt><a name="index-TARGET_005fADDR_005fSPACE_005fPOINTER_005fMODE"></a>Target Hook: <em>scalar_int_mode</em> <strong>TARGET_ADDR_SPACE_POINTER_MODE</strong> <em>(addr_space_t <var>address_space</var>)</em></dt>
|
|
<dd><p>Define this to return the machine mode to use for pointers to
|
|
<var>address_space</var> if the target supports named address spaces.
|
|
The default version of this hook returns <code>ptr_mode</code>.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-TARGET_005fADDR_005fSPACE_005fADDRESS_005fMODE"></a>Target Hook: <em>scalar_int_mode</em> <strong>TARGET_ADDR_SPACE_ADDRESS_MODE</strong> <em>(addr_space_t <var>address_space</var>)</em></dt>
|
|
<dd><p>Define this to return the machine mode to use for addresses in
|
|
<var>address_space</var> if the target supports named address spaces.
|
|
The default version of this hook returns <code>Pmode</code>.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-TARGET_005fADDR_005fSPACE_005fVALID_005fPOINTER_005fMODE"></a>Target Hook: <em>bool</em> <strong>TARGET_ADDR_SPACE_VALID_POINTER_MODE</strong> <em>(scalar_int_mode <var>mode</var>, addr_space_t <var>as</var>)</em></dt>
|
|
<dd><p>Define this to return nonzero if the port can handle pointers
|
|
with machine mode <var>mode</var> to address space <var>as</var>. This target
|
|
hook is the same as the <code>TARGET_VALID_POINTER_MODE</code> target hook,
|
|
except that it includes explicit named address space support. The default
|
|
version of this hook returns true for the modes returned by either the
|
|
<code>TARGET_ADDR_SPACE_POINTER_MODE</code> or <code>TARGET_ADDR_SPACE_ADDRESS_MODE</code>
|
|
target hooks for the given address space.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-TARGET_005fADDR_005fSPACE_005fLEGITIMATE_005fADDRESS_005fP"></a>Target Hook: <em>bool</em> <strong>TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P</strong> <em>(machine_mode <var>mode</var>, rtx <var>exp</var>, bool <var>strict</var>, addr_space_t <var>as</var>)</em></dt>
|
|
<dd><p>Define this to return true if <var>exp</var> is a valid address for mode
|
|
<var>mode</var> in the named address space <var>as</var>. The <var>strict</var>
|
|
parameter says whether strict addressing is in effect after reload has
|
|
finished. This target hook is the same as the
|
|
<code>TARGET_LEGITIMATE_ADDRESS_P</code> target hook, except that it includes
|
|
explicit named address space support.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-TARGET_005fADDR_005fSPACE_005fLEGITIMIZE_005fADDRESS"></a>Target Hook: <em>rtx</em> <strong>TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS</strong> <em>(rtx <var>x</var>, rtx <var>oldx</var>, machine_mode <var>mode</var>, addr_space_t <var>as</var>)</em></dt>
|
|
<dd><p>Define this to modify an invalid address <var>x</var> to be a valid address
|
|
with mode <var>mode</var> in the named address space <var>as</var>. This target
|
|
hook is the same as the <code>TARGET_LEGITIMIZE_ADDRESS</code> target hook,
|
|
except that it includes explicit named address space support.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-TARGET_005fADDR_005fSPACE_005fSUBSET_005fP"></a>Target Hook: <em>bool</em> <strong>TARGET_ADDR_SPACE_SUBSET_P</strong> <em>(addr_space_t <var>subset</var>, addr_space_t <var>superset</var>)</em></dt>
|
|
<dd><p>Define this to return whether the <var>subset</var> named address space is
|
|
contained within the <var>superset</var> named address space. Pointers to
|
|
a named address space that is a subset of another named address space
|
|
will be converted automatically without a cast if used together in
|
|
arithmetic operations. Pointers to a superset address space can be
|
|
converted to pointers to a subset address space via explicit casts.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-TARGET_005fADDR_005fSPACE_005fZERO_005fADDRESS_005fVALID"></a>Target Hook: <em>bool</em> <strong>TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID</strong> <em>(addr_space_t <var>as</var>)</em></dt>
|
|
<dd><p>Define this to modify the default handling of address 0 for the
|
|
address space. Return true if 0 should be considered a valid address.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-TARGET_005fADDR_005fSPACE_005fCONVERT"></a>Target Hook: <em>rtx</em> <strong>TARGET_ADDR_SPACE_CONVERT</strong> <em>(rtx <var>op</var>, tree <var>from_type</var>, tree <var>to_type</var>)</em></dt>
|
|
<dd><p>Define this to convert the pointer expression represented by the RTL
|
|
<var>op</var> with type <var>from_type</var> that points to a named address
|
|
space to a new pointer expression with type <var>to_type</var> that points
|
|
to a different named address space. When this hook it called, it is
|
|
guaranteed that one of the two address spaces is a subset of the other,
|
|
as determined by the <code>TARGET_ADDR_SPACE_SUBSET_P</code> target hook.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-TARGET_005fADDR_005fSPACE_005fDEBUG"></a>Target Hook: <em>int</em> <strong>TARGET_ADDR_SPACE_DEBUG</strong> <em>(addr_space_t <var>as</var>)</em></dt>
|
|
<dd><p>Define this to define how the address space is encoded in dwarf.
|
|
The result is the value to be used with <code>DW_AT_address_class</code>.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-TARGET_005fADDR_005fSPACE_005fDIAGNOSE_005fUSAGE"></a>Target Hook: <em>void</em> <strong>TARGET_ADDR_SPACE_DIAGNOSE_USAGE</strong> <em>(addr_space_t <var>as</var>, location_t <var>loc</var>)</em></dt>
|
|
<dd><p>Define this hook if the availability of an address space depends on
|
|
command line options and some diagnostics should be printed when the
|
|
address space is used. This hook is called during parsing and allows
|
|
to emit a better diagnostic compared to the case where the address space
|
|
was not registered with <code>c_register_addr_space</code>. <var>as</var> is
|
|
the address space as registered with <code>c_register_addr_space</code>.
|
|
<var>loc</var> is the location of the address space qualifier token.
|
|
The default implementation does nothing.
|
|
</p></dd></dl>
|
|
|
|
<hr>
|
|
<div class="header">
|
|
<p>
|
|
Next: <a href="Misc.html#Misc" accesskey="n" rel="next">Misc</a>, Previous: <a href="C_002b_002b-ABI.html#C_002b_002b-ABI" accesskey="p" rel="prev">C++ ABI</a>, Up: <a href="Target-Macros.html#Target-Macros" accesskey="u" rel="up">Target Macros</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
|
|
</div>
|
|
|
|
|
|
|
|
</body>
|
|
</html>
|