Author: vedantk
Date: Mon Aug 6 13:13:52 2018
New Revision: 339051
URL: http://llvm.org/viewvc/llvm-project?rev=339051&view=rev
Log:
[IRMemoryMap] Avoid redundant zero-init in the Allocation constructor (NFC)
In the lldb-bench/arithmetic benchmark, 1.7% of the total running time
is spent zero-initializing a std::vector that has already been zeroed.
Modified:
lldb/trunk/include/lldb/Utility/DataBufferHeap.h
lldb/trunk/source/Expression/IRMemoryMap.cpp
Modified: lldb/trunk/include/lldb/Utility/DataBufferHeap.h
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Utility/DataBufferHeap.h?rev=339051&r1=339050&r2=339051&view=diff
==============================================================================
--- lldb/trunk/include/lldb/Utility/DataBufferHeap.h (original)
+++ lldb/trunk/include/lldb/Utility/DataBufferHeap.h Mon Aug 6 13:13:52 2018
@@ -90,7 +90,8 @@ public:
/// Set the number of bytes in the data buffer.
///
/// Sets the number of bytes that this object should be able to contain.
- /// This can be used prior to copying data into the buffer.
+ /// This can be used prior to copying data into the buffer. Note that this
+ /// zero-initializes up to \p byte_size bytes.
///
/// @param[in] byte_size
/// The new size in bytes that this data buffer should attempt
Modified: lldb/trunk/source/Expression/IRMemoryMap.cpp
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Expression/IRMemoryMap.cpp?rev=339051&r1=339050&r2=339051&view=diff
==============================================================================
--- lldb/trunk/source/Expression/IRMemoryMap.cpp (original)
+++ lldb/trunk/source/Expression/IRMemoryMap.cpp Mon Aug 6 13:13:52 2018
@@ -278,15 +278,11 @@ IRMemoryMap::Allocation::Allocation(lldb
default:
assert(0 && "We cannot reach this!");
case eAllocationPolicyHostOnly:
+ case eAllocationPolicyMirror:
m_data.SetByteSize(size);
- memset(m_data.GetBytes(), 0, size);
break;
case eAllocationPolicyProcessOnly:
break;
- case eAllocationPolicyMirror:
- m_data.SetByteSize(size);
- memset(m_data.GetBytes(), 0, size);
- break;
}
}
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