[cfe-commits] r112951 - /cfe/trunk/docs/InternalsManual.html

[John McCall]

Author: rjmccall
Date: Fri Sep  3 00:07:55 2010
New Revision: 112951

URL: http://llvm.org/viewvc/llvm-project?rev=112951&view=rev
Log:
Update the internals manual for the removal of Action, as well as other
changes that are much older.


Modified:
    cfe/trunk/docs/InternalsManual.html

Modified: cfe/trunk/docs/InternalsManual.html
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/InternalsManual.html?rev=112951&r1=112950&r2=112951&view=diff
==============================================================================
--- cfe/trunk/docs/InternalsManual.html (original)
+++ cfe/trunk/docs/InternalsManual.html Fri Sep  3 00:07:55 2010
@@ -707,9 +707,10 @@
 last token replaced with the annotation token.  In the example above, it would
 be the location of the "c" identifier.</li>
 
-<li><b>void* "AnnotationValue"</b> - This contains an opaque object that the
-parser gets from Sema through an Actions module, it is passed around and Sema
-interprets it, based on the type of annotation token.</li>
+<li><b>void* "AnnotationValue"</b> - This contains an opaque object
+that the parser gets from Sema.  The parser merely preserves the
+information for Sema to later interpret based on the annotation token
+kind.</li>
 
 <li><b>TokenKind "Kind"</b> - This indicates the kind of Annotation token this
 is.  See below for the different valid kinds.</li>
@@ -719,21 +720,29 @@
 
 <ol>
 <li><b>tok::annot_typename</b>: This annotation token represents a
-resolved typename token that is potentially qualified.  The AnnotationValue
-field contains a pointer returned by Action::getTypeName().  In the case of the
-Sema actions module, this is a <tt>Decl*</tt> for the type.</li>
-
-<li><b>tok::annot_cxxscope</b>: This annotation token represents a C++ scope
-specifier, such as "A::B::".  This corresponds to the grammar productions "::"
-and ":: [opt] nested-name-specifier".  The AnnotationValue pointer is returned
-by the Action::ActOnCXXGlobalScopeSpecifier and
-Action::ActOnCXXNestedNameSpecifier callbacks.  In the case of Sema, this is a
-<tt>DeclContext*</tt>.</li>
+resolved typename token that is potentially qualified.  The
+AnnotationValue field contains the <tt>QualType</tt> returned by
+Sema::getTypeName(), possibly with source location information
+attached.</li>
+
+<li><b>tok::annot_cxxscope</b>: This annotation token represents a C++
+scope specifier, such as "A::B::".  This corresponds to the grammar
+productions "::" and ":: [opt] nested-name-specifier".  The
+AnnotationValue pointer is a <tt>NestedNameSpecifier*</tt> returned by
+the Sema::ActOnCXXGlobalScopeSpecifier and
+Sema::ActOnCXXNestedNameSpecifier callbacks.</li>
 
 <li><b>tok::annot_template_id</b>: This annotation token represents a
 C++ template-id such as "foo<int, 4>", where "foo" is the name
 of a template. The AnnotationValue pointer is a pointer to a malloc'd
-TemplateIdAnnotation object. Depending on the context, a parsed template-id that names a type might become a typename annotation token (if all we care about is the named type, e.g., because it occurs in a type specifier) or might remain a template-id token (if we want to retain more source location information or produce a new type, e.g., in a declaration of a class template specialization). template-id annotation tokens that refer to a type can be "upgraded" to typename annotation tokens by the parser.</li>
+TemplateIdAnnotation object. Depending on the context, a parsed
+template-id that names a type might become a typename annotation token
+(if all we care about is the named type, e.g., because it occurs in a
+type specifier) or might remain a template-id token (if we want to
+retain more source location information or produce a new type, e.g.,
+in a declaration of a class template specialization). template-id
+annotation tokens that refer to a type can be "upgraded" to typename
+annotation tokens by the parser.</li>
 
 </ol>
 
@@ -953,11 +962,12 @@
 <h3 id="QualType">The QualType class</h3>
 <!-- ======================================================================= -->
 
-<p>The QualType class is designed as a trivial value class that is small,
-passed by-value and is efficient to query.  The idea of QualType is that it
-stores the type qualifiers (const, volatile, restrict) separately from the types
-themselves: QualType is conceptually a pair of "Type*" and bits for the type
-qualifiers.</p>
+<p>The QualType class is designed as a trivial value class that is
+small, passed by-value and is efficient to query.  The idea of
+QualType is that it stores the type qualifiers (const, volatile,
+restrict, plus some extended qualifiers required by language
+extensions) separately from the types themselves.  QualType is
+conceptually a pair of "Type*" and the bits for these type qualifiers.</p>
 
 <p>By storing the type qualifiers as bits in the conceptual pair, it is
 extremely efficient to get the set of qualifiers on a QualType (just return the
@@ -972,10 +982,11 @@
 used to represent bits and also means we do not have to consider qualifiers when
 uniquing types (<a href="#Type">Type</a> does not even contain qualifiers).</p>
 
-<p>In practice, on hosts where it is safe, the 3 type qualifiers are stored in
-the low bit of the pointer to the Type object.  This means that QualType is
-exactly the same size as a pointer, and this works fine on any system where
-malloc'd objects are at least 8 byte aligned.</p>
+<p>In practice, the two most common type qualifiers (const and
+restrict) are stored in the low bits of the pointer to the Type
+object, together with a flag indicating whether extended qualifiers
+are present (which must be heap-allocated).  This means that QualType
+is exactly the same size as a pointer.</p>
 
 <!-- ======================================================================= -->
 <h3 id="DeclarationName">Declaration names</h3>