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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:44:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:44:51 +0000 |
commit | 9e3c08db40b8916968b9f30096c7be3f00ce9647 (patch) | |
tree | a68f146d7fa01f0134297619fbe7e33db084e0aa /xpcom/tests/SizeTest01.cpp | |
parent | Initial commit. (diff) | |
download | thunderbird-9e3c08db40b8916968b9f30096c7be3f00ce9647.tar.xz thunderbird-9e3c08db40b8916968b9f30096c7be3f00ce9647.zip |
Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | xpcom/tests/SizeTest01.cpp | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/xpcom/tests/SizeTest01.cpp b/xpcom/tests/SizeTest01.cpp new file mode 100644 index 0000000000..790b0fa032 --- /dev/null +++ b/xpcom/tests/SizeTest01.cpp @@ -0,0 +1,107 @@ +// Test01.cpp + +#include "nsINode.h" +#include "nsCOMPtr.h" +#include "nsString.h" + +NS_DEF_PTR(nsINode); + +/* + This test file compares the generated code size of similar functions + between raw COM interface pointers (|AddRef|ing and |Release|ing by hand) and + |nsCOMPtr|s. + + Function size results were determined by examining dissassembly of the + generated code. mXXX is the size of the generated code on the Macintosh. wXXX + is the size on Windows. For these tests, all reasonable optimizations were + enabled and exceptions were disabled (just as we build for release). + + The tests in this file explore only the simplest functionality: + assigning a pointer to be reference counted into a [raw, nsCOMPtr] object; + ensuring that it is |AddRef|ed and |Release|d appropriately; calling through + the pointer to a function supplied by the underlying COM interface. + + Windows: + raw_optimized + 31 bytes raw, nsCOMPtr* + 34 nsCOMPtr_optimized* + 38 nsCOMPtr_optimized + 42 nsCOMPtr + 46 + + Macintosh: + raw_optimized, nsCOMPtr_optimized + 112 bytes (1.0000) nsCOMPtr + 120 (1.0714) i.e., 7.14% bigger than + raw_optimized et al + raw + 140 (1.2500) + + The overall difference in size between Windows and Macintosh is caused + by the the PowerPC RISC architecture where every instruction is 4 bytes. + + On Macintosh, nsCOMPtr generates out-of-line destructors which are + not referenced, and which can be stripped by the linker. +*/ + +void Test01_raw(nsINode* aDOMNode, nsString* aResult) +// m140, w34 +{ + /* + This test is designed to be more like a typical large function where, + because you are working with several resources, you don't just return + when one of them is |nullptr|. Similarly: |Test01_nsCOMPtr00|, and + |Test01_nsIPtr00|. + */ + + nsINode* node = aDOMNode; + NS_IF_ADDREF(node); + + if (node) node->GetNodeName(*aResult); + + NS_IF_RELEASE(node); +} + +void Test01_raw_optimized(nsINode* aDOMNode, nsString* aResult) +// m112, w31 +{ + /* + This test simulates smaller functions where you _do_ just return + |nullptr| at the first sign of trouble. Similarly: + |Test01_nsCOMPtr01|, and |Test01_nsIPtr01|. + */ + + /* + This test produces smaller code that |Test01_raw| because it avoids + the three tests: |NS_IF_...|, and |if ( node )|. + */ + + // -- the following code is assumed, but is commented out so we compare only + // the relevent generated code + + // if ( !aDOMNode ) + // return; + + nsINode* node = aDOMNode; + NS_ADDREF(node); + node->GetNodeName(*aResult); + NS_RELEASE(node); +} + +void Test01_nsCOMPtr(nsINode* aDOMNode, nsString* aResult) +// m120, w46/34 +{ + nsCOMPtr<nsINode> node = aDOMNode; + + if (node) node->GetNodeName(*aResult); +} + +void Test01_nsCOMPtr_optimized(nsINode* aDOMNode, nsString* aResult) +// m112, w42/38 +{ + // if ( !aDOMNode ) + // return; + + nsCOMPtr<nsINode> node = aDOMNode; + node->GetNodeName(*aResult); +} |