forked from mirrors/gecko-dev
6f45c666bc
# ignore-this-changeset Differential Revision: https://phabricator.services.mozilla.com/D14595 --HG-- extra : moz-landing-system : lando
107 lines
3 KiB
C++
107 lines
3 KiB
C++
// Test01.cpp
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#include "nsINode.h"
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#include "nsCOMPtr.h"
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#include "nsString.h"
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NS_DEF_PTR(nsINode);
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/*
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This test file compares the generated code size of similar functions
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between raw COM interface pointers (|AddRef|ing and |Release|ing by hand) and
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|nsCOMPtr|s.
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Function size results were determined by examining dissassembly of the
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generated code. mXXX is the size of the generated code on the Macintosh. wXXX
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is the size on Windows. For these tests, all reasonable optimizations were
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enabled and exceptions were disabled (just as we build for release).
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The tests in this file explore only the simplest functionality:
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assigning a pointer to be reference counted into a [raw, nsCOMPtr] object;
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ensuring that it is |AddRef|ed and |Release|d appropriately; calling through
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the pointer to a function supplied by the underlying COM interface.
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Windows:
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raw_optimized
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31 bytes raw, nsCOMPtr*
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34 nsCOMPtr_optimized*
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38 nsCOMPtr_optimized
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42 nsCOMPtr
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46
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Macintosh:
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raw_optimized, nsCOMPtr_optimized
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112 bytes (1.0000) nsCOMPtr
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120 (1.0714) i.e., 7.14% bigger than
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raw_optimized et al
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raw
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140 (1.2500)
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The overall difference in size between Windows and Macintosh is caused
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by the the PowerPC RISC architecture where every instruction is 4 bytes.
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On Macintosh, nsCOMPtr generates out-of-line destructors which are
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not referenced, and which can be stripped by the linker.
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*/
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void Test01_raw(nsINode* aDOMNode, nsString* aResult)
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// m140, w34
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{
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/*
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This test is designed to be more like a typical large function where,
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because you are working with several resources, you don't just return
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when one of them is |nullptr|. Similarly: |Test01_nsCOMPtr00|, and
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|Test01_nsIPtr00|.
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*/
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nsINode* node = aDOMNode;
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NS_IF_ADDREF(node);
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if (node) node->GetNodeName(*aResult);
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NS_IF_RELEASE(node);
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}
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void Test01_raw_optimized(nsINode* aDOMNode, nsString* aResult)
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// m112, w31
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{
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/*
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This test simulates smaller functions where you _do_ just return
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|nullptr| at the first sign of trouble. Similarly:
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|Test01_nsCOMPtr01|, and |Test01_nsIPtr01|.
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*/
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/*
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This test produces smaller code that |Test01_raw| because it avoids
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the three tests: |NS_IF_...|, and |if ( node )|.
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*/
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// -- the following code is assumed, but is commented out so we compare only
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// the relevent generated code
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// if ( !aDOMNode )
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// return;
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nsINode* node = aDOMNode;
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NS_ADDREF(node);
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node->GetNodeName(*aResult);
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NS_RELEASE(node);
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}
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void Test01_nsCOMPtr(nsINode* aDOMNode, nsString* aResult)
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// m120, w46/34
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{
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nsCOMPtr<nsINode> node = aDOMNode;
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if (node) node->GetNodeName(*aResult);
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}
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void Test01_nsCOMPtr_optimized(nsINode* aDOMNode, nsString* aResult)
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// m112, w42/38
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{
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// if ( !aDOMNode )
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// return;
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nsCOMPtr<nsINode> node = aDOMNode;
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node->GetNodeName(*aResult);
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}
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