1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/tests/SizeTest01.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,107 @@
1.4 +// Test01.cpp
1.5 +
1.6 +#include "nsIDOMNode.h"
1.7 +#include "nsCOMPtr.h"
1.8 +#include "nsString.h"
1.9 +
1.10 +NS_DEF_PTR(nsIDOMNode);
1.11 +
1.12 + /*
1.13 + This test file compares the generated code size of similar functions between raw
1.14 + COM interface pointers (|AddRef|ing and |Release|ing by hand) and |nsCOMPtr|s.
1.15 +
1.16 + Function size results were determined by examining dissassembly of the generated code.
1.17 + mXXX is the size of the generated code on the Macintosh. wXXX is the size on Windows.
1.18 + For these tests, all reasonable optimizations were enabled and exceptions were
1.19 + disabled (just as we build for release).
1.20 +
1.21 + The tests in this file explore only the simplest functionality: assigning a pointer
1.22 + to be reference counted into a [raw, nsCOMPtr] object; ensuring that it is
1.23 + |AddRef|ed and |Release|d appropriately; calling through the pointer to a function
1.24 + supplied by the underlying COM interface.
1.25 +
1.26 + Windows:
1.27 + raw_optimized 31 bytes
1.28 + raw, nsCOMPtr* 34
1.29 + nsCOMPtr_optimized* 38
1.30 + nsCOMPtr_optimized 42
1.31 + nsCOMPtr 46
1.32 +
1.33 + Macintosh:
1.34 + raw_optimized, nsCOMPtr_optimized 112 bytes (1.0000)
1.35 + nsCOMPtr 120 (1.0714) i.e., 7.14% bigger than raw_optimized et al
1.36 + raw 140 (1.2500)
1.37 +
1.38 + The overall difference in size between Windows and Macintosh is caused by the
1.39 + the PowerPC RISC architecture where every instruction is 4 bytes.
1.40 +
1.41 + On Macintosh, nsCOMPtr generates out-of-line destructors which are
1.42 + not referenced, and which can be stripped by the linker.
1.43 + */
1.44 +
1.45 +void
1.46 +Test01_raw( nsIDOMNode* aDOMNode, nsString* aResult )
1.47 + // m140, w34
1.48 + {
1.49 + /*
1.50 + This test is designed to be more like a typical large function where,
1.51 + because you are working with several resources, you don't just return when
1.52 + one of them is |nullptr|. Similarly: |Test01_nsCOMPtr00|, and |Test01_nsIPtr00|.
1.53 + */
1.54 +
1.55 + nsIDOMNode* node = aDOMNode;
1.56 + NS_IF_ADDREF(node);
1.57 +
1.58 + if ( node )
1.59 + node->GetNodeName(*aResult);
1.60 +
1.61 + NS_IF_RELEASE(node);
1.62 + }
1.63 +
1.64 +void
1.65 +Test01_raw_optimized( nsIDOMNode* aDOMNode, nsString* aResult )
1.66 + // m112, w31
1.67 + {
1.68 + /*
1.69 + This test simulates smaller functions where you _do_ just return
1.70 + |nullptr| at the first sign of trouble. Similarly: |Test01_nsCOMPtr01|,
1.71 + and |Test01_nsIPtr01|.
1.72 + */
1.73 +
1.74 + /*
1.75 + This test produces smaller code that |Test01_raw| because it avoids
1.76 + the three tests: |NS_IF_...|, and |if ( node )|.
1.77 + */
1.78 +
1.79 +// -- the following code is assumed, but is commented out so we compare only
1.80 +// the relevent generated code
1.81 +
1.82 +// if ( !aDOMNode )
1.83 +// return;
1.84 +
1.85 + nsIDOMNode* node = aDOMNode;
1.86 + NS_ADDREF(node);
1.87 + node->GetNodeName(*aResult);
1.88 + NS_RELEASE(node);
1.89 + }
1.90 +
1.91 +void
1.92 +Test01_nsCOMPtr( nsIDOMNode* aDOMNode, nsString* aResult )
1.93 + // m120, w46/34
1.94 + {
1.95 + nsCOMPtr<nsIDOMNode> node = aDOMNode;
1.96 +
1.97 + if ( node )
1.98 + node->GetNodeName(*aResult);
1.99 + }
1.100 +
1.101 +void
1.102 +Test01_nsCOMPtr_optimized( nsIDOMNode* aDOMNode, nsString* aResult )
1.103 + // m112, w42/38
1.104 + {
1.105 +// if ( !aDOMNode )
1.106 +// return;
1.107 +
1.108 + nsCOMPtr<nsIDOMNode> node = aDOMNode;
1.109 + node->GetNodeName(*aResult);
1.110 + }
