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| <a name="References-to-storage"></a> |
| <h4 class="subsection">10.6.2 References to storage</h4> |
| <a name="index-ADDR_005fEXPR"></a> |
| <a name="index-INDIRECT_005fREF"></a> |
| <a name="index-MEM_005fREF"></a> |
| <a name="index-ARRAY_005fREF"></a> |
| <a name="index-ARRAY_005fRANGE_005fREF"></a> |
| <a name="index-TARGET_005fMEM_005fREF"></a> |
| <a name="index-COMPONENT_005fREF"></a> |
| |
| <dl compact="compact"> |
| <dt><code>ARRAY_REF</code></dt> |
| <dd><p>These nodes represent array accesses. The first operand is the array; |
| the second is the index. To calculate the address of the memory |
| accessed, you must scale the index by the size of the type of the array |
| elements. The type of these expressions must be the type of a component of |
| the array. The third and fourth operands are used after gimplification |
| to represent the lower bound and component size but should not be used |
| directly; call <code>array_ref_low_bound</code> and <code>array_ref_element_size</code> |
| instead. |
| </p> |
| </dd> |
| <dt><code>ARRAY_RANGE_REF</code></dt> |
| <dd><p>These nodes represent access to a range (or “slice”) of an array. The |
| operands are the same as that for <code>ARRAY_REF</code> and have the same |
| meanings. The type of these expressions must be an array whose component |
| type is the same as that of the first operand. The range of that array |
| type determines the amount of data these expressions access. |
| </p> |
| </dd> |
| <dt><code>TARGET_MEM_REF</code></dt> |
| <dd><p>These nodes represent memory accesses whose address directly map to |
| an addressing mode of the target architecture. The first argument |
| is <code>TMR_SYMBOL</code> and must be a <code>VAR_DECL</code> of an object with |
| a fixed address. The second argument is <code>TMR_BASE</code> and the |
| third one is <code>TMR_INDEX</code>. The fourth argument is |
| <code>TMR_STEP</code> and must be an <code>INTEGER_CST</code>. The fifth |
| argument is <code>TMR_OFFSET</code> and must be an <code>INTEGER_CST</code>. |
| Any of the arguments may be NULL if the appropriate component |
| does not appear in the address. Address of the <code>TARGET_MEM_REF</code> |
| is determined in the following way. |
| </p> |
| <div class="smallexample"> |
| <pre class="smallexample">&TMR_SYMBOL + TMR_BASE + TMR_INDEX * TMR_STEP + TMR_OFFSET |
| </pre></div> |
| |
| <p>The sixth argument is the reference to the original memory access, which |
| is preserved for the purposes of the RTL alias analysis. The seventh |
| argument is a tag representing the results of tree level alias analysis. |
| </p> |
| </dd> |
| <dt><code>ADDR_EXPR</code></dt> |
| <dd><p>These nodes are used to represent the address of an object. (These |
| expressions will always have pointer or reference type.) The operand may |
| be another expression, or it may be a declaration. |
| </p> |
| <p>As an extension, GCC allows users to take the address of a label. In |
| this case, the operand of the <code>ADDR_EXPR</code> will be a |
| <code>LABEL_DECL</code>. The type of such an expression is <code>void*</code>. |
| </p> |
| <p>If the object addressed is not an lvalue, a temporary is created, and |
| the address of the temporary is used. |
| </p> |
| </dd> |
| <dt><code>INDIRECT_REF</code></dt> |
| <dd><p>These nodes are used to represent the object pointed to by a pointer. |
| The operand is the pointer being dereferenced; it will always have |
| pointer or reference type. |
| </p> |
| </dd> |
| <dt><code>MEM_REF</code></dt> |
| <dd><p>These nodes are used to represent the object pointed to by a pointer |
| offset by a constant. |
| The first operand is the pointer being dereferenced; it will always have |
| pointer or reference type. The second operand is a pointer constant. |
| Its type is specifying the type to be used for type-based alias analysis. |
| </p> |
| </dd> |
| <dt><code>COMPONENT_REF</code></dt> |
| <dd><p>These nodes represent non-static data member accesses. The first |
| operand is the object (rather than a pointer to it); the second operand |
| is the <code>FIELD_DECL</code> for the data member. The third operand represents |
| the byte offset of the field, but should not be used directly; call |
| <code>component_ref_field_offset</code> instead. |
| </p> |
| |
| </dd> |
| </dl> |
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