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diff --git a/share/doc/gccint/Dispatch-Tables.html b/share/doc/gccint/Dispatch-Tables.html new file mode 100644 index 0000000..6293b74 --- /dev/null +++ b/share/doc/gccint/Dispatch-Tables.html @@ -0,0 +1,228 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1988-2023 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 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>GNU Compiler Collection (GCC) Internals: Dispatch Tables</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Dispatch Tables"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Dispatch Tables"> +<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="Assembler-Format.html#Assembler-Format" rel="up" title="Assembler Format"> +<link href="Exception-Region-Output.html#Exception-Region-Output" rel="next" title="Exception Region Output"> +<link href="Instruction-Output.html#Instruction-Output" rel="previous" title="Instruction Output"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +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.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Dispatch-Tables"></a> +<div class="header"> +<p> +Next: <a href="Exception-Region-Output.html#Exception-Region-Output" accesskey="n" rel="next">Exception Region Output</a>, Previous: <a href="Instruction-Output.html#Instruction-Output" accesskey="p" rel="previous">Instruction Output</a>, Up: <a href="Assembler-Format.html#Assembler-Format" accesskey="u" rel="up">Assembler Format</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="Output-of-Dispatch-Tables"></a> +<h4 class="subsection">18.20.8 Output of Dispatch Tables</h4> + +<p>This concerns dispatch tables. +</p> +<a name="index-dispatch-table"></a> +<dl> +<dt><a name="index-ASM_005fOUTPUT_005fADDR_005fDIFF_005fELT"></a>Macro: <strong>ASM_OUTPUT_ADDR_DIFF_ELT</strong> <em>(<var>stream</var>, <var>body</var>, <var>value</var>, <var>rel</var>)</em></dt> +<dd><p>A C statement to output to the stdio stream <var>stream</var> an assembler +pseudo-instruction to generate a difference between two labels. +<var>value</var> and <var>rel</var> are the numbers of two internal labels. The +definitions of these labels are output using +<code>(*targetm.asm_out.internal_label)</code>, and they must be printed in the same +way here. For example, +</p> +<div class="smallexample"> +<pre class="smallexample">fprintf (<var>stream</var>, "\t.word L%d-L%d\n", + <var>value</var>, <var>rel</var>) +</pre></div> + +<p>You must provide this macro on machines where the addresses in a +dispatch table are relative to the table’s own address. If defined, GCC +will also use this macro on all machines when producing PIC. +<var>body</var> is the body of the <code>ADDR_DIFF_VEC</code>; it is provided so that the +mode and flags can be read. +</p></dd></dl> + +<dl> +<dt><a name="index-ASM_005fOUTPUT_005fADDR_005fVEC_005fELT"></a>Macro: <strong>ASM_OUTPUT_ADDR_VEC_ELT</strong> <em>(<var>stream</var>, <var>value</var>)</em></dt> +<dd><p>This macro should be provided on machines where the addresses +in a dispatch table are absolute. +</p> +<p>The definition should be a C statement to output to the stdio stream +<var>stream</var> an assembler pseudo-instruction to generate a reference to +a label. <var>value</var> is the number of an internal label whose +definition is output using <code>(*targetm.asm_out.internal_label)</code>. +For example, +</p> +<div class="smallexample"> +<pre class="smallexample">fprintf (<var>stream</var>, "\t.word L%d\n", <var>value</var>) +</pre></div> +</dd></dl> + +<dl> +<dt><a name="index-ASM_005fOUTPUT_005fCASE_005fLABEL"></a>Macro: <strong>ASM_OUTPUT_CASE_LABEL</strong> <em>(<var>stream</var>, <var>prefix</var>, <var>num</var>, <var>table</var>)</em></dt> +<dd><p>Define this if the label before a jump-table needs to be output +specially. The first three arguments are the same as for +<code>(*targetm.asm_out.internal_label)</code>; the fourth argument is the +jump-table which follows (a <code>jump_table_data</code> containing an +<code>addr_vec</code> or <code>addr_diff_vec</code>). +</p> +<p>This feature is used on system V to output a <code>swbeg</code> statement +for the table. +</p> +<p>If this macro is not defined, these labels are output with +<code>(*targetm.asm_out.internal_label)</code>. +</p></dd></dl> + +<dl> +<dt><a name="index-ASM_005fOUTPUT_005fCASE_005fEND"></a>Macro: <strong>ASM_OUTPUT_CASE_END</strong> <em>(<var>stream</var>, <var>num</var>, <var>table</var>)</em></dt> +<dd><p>Define this if something special must be output at the end of a +jump-table. The definition should be a C statement to be executed +after the assembler code for the table is written. It should write +the appropriate code to stdio stream <var>stream</var>. The argument +<var>table</var> is the jump-table insn, and <var>num</var> is the label-number +of the preceding label. +</p> +<p>If this macro is not defined, nothing special is output at the end of +the jump-table. +</p></dd></dl> + +<dl> +<dt><a name="index-TARGET_005fASM_005fPOST_005fCFI_005fSTARTPROC"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_POST_CFI_STARTPROC</strong> <em>(FILE *<var></var>, <var>tree</var>)</em></dt> +<dd><p>This target hook is used to emit assembly strings required by the target +after the .cfi_startproc directive. The first argument is the file stream to +write the strings to and the second argument is the function’s declaration. The +expected use is to add more .cfi_* directives. +</p> +<p>The default is to not output any assembly strings. +</p></dd></dl> + +<dl> +<dt><a name="index-TARGET_005fASM_005fEMIT_005fUNWIND_005fLABEL"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_EMIT_UNWIND_LABEL</strong> <em>(FILE *<var>stream</var>, tree <var>decl</var>, int <var>for_eh</var>, int <var>empty</var>)</em></dt> +<dd><p>This target hook emits a label at the beginning of each FDE. It +should be defined on targets where FDEs need special labels, and it +should write the appropriate label, for the FDE associated with the +function declaration <var>decl</var>, to the stdio stream <var>stream</var>. +The third argument, <var>for_eh</var>, is a boolean: true if this is for an +exception table. The fourth argument, <var>empty</var>, is a boolean: +true if this is a placeholder label for an omitted FDE. +</p> +<p>The default is that FDEs are not given nonlocal labels. +</p></dd></dl> + +<dl> +<dt><a name="index-TARGET_005fASM_005fEMIT_005fEXCEPT_005fTABLE_005fLABEL"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL</strong> <em>(FILE *<var>stream</var>)</em></dt> +<dd><p>This target hook emits a label at the beginning of the exception table. +It should be defined on targets where it is desirable for the table +to be broken up according to function. +</p> +<p>The default is that no label is emitted. +</p></dd></dl> + +<dl> +<dt><a name="index-TARGET_005fASM_005fEMIT_005fEXCEPT_005fPERSONALITY"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_EMIT_EXCEPT_PERSONALITY</strong> <em>(rtx <var>personality</var>)</em></dt> +<dd><p>If the target implements <code>TARGET_ASM_UNWIND_EMIT</code>, this hook may be +used to emit a directive to install a personality hook into the unwind +info. This hook should not be used if dwarf2 unwind info is used. +</p></dd></dl> + +<dl> +<dt><a name="index-TARGET_005fASM_005fUNWIND_005fEMIT"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_UNWIND_EMIT</strong> <em>(FILE *<var>stream</var>, rtx_insn *<var>insn</var>)</em></dt> +<dd><p>This target hook emits assembly directives required to unwind the +given instruction. This is only used when <code>TARGET_EXCEPT_UNWIND_INFO</code> +returns <code>UI_TARGET</code>. +</p></dd></dl> + +<dl> +<dt><a name="index-TARGET_005fASM_005fMAKE_005fEH_005fSYMBOL_005fINDIRECT"></a>Target Hook: <em>rtx</em> <strong>TARGET_ASM_MAKE_EH_SYMBOL_INDIRECT</strong> <em>(rtx <var>origsymbol</var>, bool <var>pubvis</var>)</em></dt> +<dd><p>If necessary, modify personality and LSDA references to handle indirection. +The original symbol is in <code>origsymbol</code> and if <code>pubvis</code> is true +the symbol is visible outside the TU. +</p></dd></dl> + +<dl> +<dt><a name="index-TARGET_005fASM_005fUNWIND_005fEMIT_005fBEFORE_005fINSN"></a>Target Hook: <em>bool</em> <strong>TARGET_ASM_UNWIND_EMIT_BEFORE_INSN</strong></dt> +<dd><p>True if the <code>TARGET_ASM_UNWIND_EMIT</code> hook should be called before +the assembly for <var>insn</var> has been emitted, false if the hook should +be called afterward. +</p></dd></dl> + +<dl> +<dt><a name="index-TARGET_005fASM_005fSHOULD_005fRESTORE_005fCFA_005fSTATE"></a>Target Hook: <em>bool</em> <strong>TARGET_ASM_SHOULD_RESTORE_CFA_STATE</strong> <em>(void)</em></dt> +<dd><p>For DWARF-based unwind frames, two CFI instructions provide for save and +restore of register state. GCC maintains the current frame address (CFA) +separately from the register bank but the unwinder in libgcc preserves this +state along with the registers (and this is expected by the code that writes +the unwind frames). This hook allows the target to specify that the CFA data +is not saved/restored along with the registers by the target unwinder so that +suitable additional instructions should be emitted to restore it. +</p></dd></dl> + +<hr> +<div class="header"> +<p> +Next: <a href="Exception-Region-Output.html#Exception-Region-Output" accesskey="n" rel="next">Exception Region Output</a>, Previous: <a href="Instruction-Output.html#Instruction-Output" accesskey="p" rel="previous">Instruction Output</a>, Up: <a href="Assembler-Format.html#Assembler-Format" accesskey="u" rel="up">Assembler Format</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> |