[llvm-commits] CVS: llvm/docs/LangRef.html
Andrew Lenharth
alenhar2 at cs.uiuc.edu
Sat Jun 18 11:28:29 PDT 2005
Changes in directory llvm/docs:
LangRef.html updated: 1.108 -> 1.109
---
Log message:
OK, after checking the backwards compatibility code on X86 and the new code
path on alpha, now has come the time for new vararg support. So, with out
further ado, I revert behavior back a couple of years!
Well, ok, I lied. A few more notes.
First, the Simple ISels cannot be expected to work any longer, but they
should still compile
Second, there are likely some bugs to track down once the nightly testers
start with this.
Third, the initial patch doesn't include sparcv9, but I'll do that today.
Forth, subsequent patches won't bother being long winded.
---
Diffs of the changes: (+50 -93)
LangRef.html | 143 ++++++++++++++++++++---------------------------------------
1 files changed, 50 insertions(+), 93 deletions(-)
Index: llvm/docs/LangRef.html
diff -u llvm/docs/LangRef.html:1.108 llvm/docs/LangRef.html:1.109
--- llvm/docs/LangRef.html:1.108 Mon May 16 11:17:45 2005
+++ llvm/docs/LangRef.html Sat Jun 18 13:28:17 2005
@@ -101,7 +101,6 @@
<li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li>
<li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
<li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
- <li><a href="#i_vanext">'<tt>vanext</tt>' Instruction</a></li>
<li><a href="#i_vaarg">'<tt>vaarg</tt>' Instruction</a></li>
</ol>
</li>
@@ -2211,58 +2210,6 @@
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
- <a name="i_vanext">'<tt>vanext</tt>' Instruction</a>
-</div>
-
-<div class="doc_text">
-
-<h5>Syntax:</h5>
-
-<pre>
- <resultarglist> = vanext <va_list> <arglist>, <argty>
-</pre>
-
-<h5>Overview:</h5>
-
-<p>The '<tt>vanext</tt>' instruction is used to access arguments passed
-through the "variable argument" area of a function call. It is used to
-implement the <tt>va_arg</tt> macro in C.</p>
-
-<h5>Arguments:</h5>
-
-<p>This instruction takes a <tt>va_list</tt> value and the type of the
-argument. It returns another <tt>va_list</tt>. The actual type of
-<tt>va_list</tt> may be defined differently for different targets. Most targets
-use a <tt>va_list</tt> type of <tt>sbyte*</tt> or some other pointer type.</p>
-
-<h5>Semantics:</h5>
-
-<p>The '<tt>vanext</tt>' instruction advances the specified <tt>va_list</tt>
-past an argument of the specified type. In conjunction with the <a
- href="#i_vaarg"><tt>vaarg</tt></a> instruction, it is used to implement
-the <tt>va_arg</tt> macro available in C. For more information, see
-the variable argument handling <a href="#int_varargs">Intrinsic
-Functions</a>.</p>
-
-<p>It is legal for this instruction to be called in a function which
-does not take a variable number of arguments, for example, the <tt>vfprintf</tt>
-function.</p>
-
-<p><tt>vanext</tt> is an LLVM instruction instead of an <a
-href="#intrinsics">intrinsic function</a> because it takes a type as an
-argument. The type refers to the current argument in the <tt>va_list</tt>; it
-tells the compiler how far on the stack it needs to advance to find the next
-argument.</p>
-
-<h5>Example:</h5>
-
-<p>See the <a href="#int_varargs">variable argument processing</a>
-section.</p>
-
-</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
<a name="i_vaarg">'<tt>vaarg</tt>' Instruction</a>
</div>
@@ -2271,34 +2218,35 @@
<h5>Syntax:</h5>
<pre>
- <resultval> = vaarg <va_list> <arglist>, <argty>
+ <resultval> = va_arg <va_list*> <arglist>, <argty>
</pre>
<h5>Overview:</h5>
-<p>The '<tt>vaarg</tt>' instruction is used to access arguments passed through
+<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
the "variable argument" area of a function call. It is used to implement the
<tt>va_arg</tt> macro in C.</p>
<h5>Arguments:</h5>
-<p>This instruction takes a <tt>va_list</tt> value and the type of the
-argument. It returns a value of the specified argument type. Again, the actual
-type of <tt>va_list</tt> is target specific.</p>
+<p>This instruction takes a <tt>va_list*</tt> value and the type of
+the argument. It returns a value of the specified argument type and
+increments the <tt>va_list</tt> to poin to the next argument. Again, the
+actual type of <tt>va_list</tt> is target specific.</p>
<h5>Semantics:</h5>
-<p>The '<tt>vaarg</tt>' instruction loads an argument of the specified type from
-the specified <tt>va_list</tt>. In conjunction with the <a
-href="#i_vanext"><tt>vanext</tt></a> instruction, it is used to implement the
-<tt>va_arg</tt> macro available in C. For more information, see the variable
-argument handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
+<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
+type from the specified <tt>va_list</tt> and causes the
+<tt>va_list</tt> to point to the next argument. For more information,
+see the variable argument handling <a href="#int_varargs">Intrinsic
+Functions</a>.</p>
<p>It is legal for this instruction to be called in a function which does not
take a variable number of arguments, for example, the <tt>vfprintf</tt>
function.</p>
-<p><tt>vaarg</tt> is an LLVM instruction instead of an <a
+<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
href="#intrinsics">intrinsic function</a> because it takes a type as an
argument.</p>
@@ -2361,20 +2309,20 @@
<pre>
int %test(int %X, ...) {
; Initialize variable argument processing
- %ap = call sbyte* %<a href="#i_va_start">llvm.va_start</a>()
+ %ap = alloca sbyte*
+ call void %<a href="#i_va_start">llvm.va_start</a>(sbyte** %ap)
; Read a single integer argument
- %tmp = vaarg sbyte* %ap, int
-
- ; Advance to the next argument
- %ap2 = vanext sbyte* %ap, int
+ %tmp = va_arg sbyte** %ap, int
; Demonstrate usage of llvm.va_copy and llvm.va_end
- %aq = call sbyte* %<a href="#i_va_copy">llvm.va_copy</a>(sbyte* %ap2)
- call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %aq)
+ %aq = alloca sbyte*
+ %apv = load sbyte** %ap
+ call void %<a href="#i_va_copy">llvm.va_copy</a>(sbyte** %aq, sbyte* %apv)
+ call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %aq)
; Stop processing of arguments.
- call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %ap2)
+ call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %ap)
ret int %tmp
}
</pre>
@@ -2388,19 +2336,25 @@
<div class="doc_text">
<h5>Syntax:</h5>
-<pre> declare <va_list> %llvm.va_start()<br></pre>
+<pre> declare void %llvm.va_start(<va_list>* <arglist>)<br></pre>
<h5>Overview:</h5>
-<p>The '<tt>llvm.va_start</tt>' intrinsic returns a new <tt><arglist></tt>
-for subsequent use by the variable argument intrinsics.</p>
+<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
+<tt>*<arglist></tt> for subsequent use by <tt><a
+href="#i_va_arg">va_arg</a></tt>.</p>
+
+<h5>Arguments:</h5>
+
+<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
+
<h5>Semantics:</h5>
-<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
-macro available in C. In a target-dependent way, it initializes and
-returns a <tt>va_list</tt> element, so that the next <tt>vaarg</tt>
-will produce the first variable argument passed to the function. Unlike
-the C <tt>va_start</tt> macro, this intrinsic does not need to know the
-last argument of the function; the compiler can figure that out.</p>
-<p>Note that this intrinsic function is only legal to be called from
-within the body of a variable argument function.</p>
+
+<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
+macro available in C. In a target-dependent way, it initializes the
+<tt>va_list</tt> element the argument points to, so that the next call to
+<tt>va_arg</tt> will produce the first variable argument passed to the function.
+Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
+last argument of the function, the compiler can figure that out.</p>
+
</div>
<!-- _______________________________________________________________________ -->
@@ -2410,7 +2364,7 @@
<div class="doc_text">
<h5>Syntax:</h5>
-<pre> declare void %llvm.va_end(<va_list> <arglist>)<br></pre>
+<pre> declare void %llvm.va_end(<va_list*> <arglist>)<br></pre>
<h5>Overview:</h5>
<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt><arglist></tt>
which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
@@ -2435,24 +2389,27 @@
<h5>Syntax:</h5>
<pre>
- declare <va_list> %llvm.va_copy(<va_list> <destarglist>)
+ declare void %llvm.va_copy(<va_list>* <destarglist>,
+ <va_list> <srcarglist>)
</pre>
<h5>Overview:</h5>
-<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
-from the source argument list to the destination argument list.</p>
+<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
+the source argument list to the destination argument list.</p>
<h5>Arguments:</h5>
-<p>The argument is the <tt>va_list</tt> to copy.</p>
+<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
+The second argument is a <tt>va_list</tt> element to copy from.</p>
+
<h5>Semantics:</h5>
-<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
-macro available in C. In a target-dependent way, it copies the source
-<tt>va_list</tt> element into the returned list. This intrinsic is necessary
-because the <tt><a href="#i_va_start">llvm.va_start</a></tt> intrinsic may be
+<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
+available in C. In a target-dependent way, it copies the source
+<tt>va_list</tt> element into the destination list. This intrinsic is necessary
+because the <tt><a href="i_va_begin">llvm.va_begin</a></tt> intrinsic may be
arbitrarily complex and require memory allocation, for example.</p>
</div>
@@ -3305,7 +3262,7 @@
<a href="mailto:sabre at nondot.org">Chris Lattner</a><br>
<a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
- Last modified: $Date: 2005/05/16 16:17:45 $
+ Last modified: $Date: 2005/06/18 18:28:17 $
</address>
</body>
</html>
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