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author | Dimitry Andric <dim@FreeBSD.org> | 2020-07-31 21:22:58 +0000 |
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committer | Dimitry Andric <dim@FreeBSD.org> | 2020-07-31 21:22:58 +0000 |
commit | 5ffd83dbcc34f10e07f6d3e968ae6365869615f4 (patch) | |
tree | 0e9f5cf729dde39f949698fddef45a34e2bc7f44 /contrib/llvm-project/lldb/source/Utility/ConstString.cpp | |
parent | 1799696096df87b52968b8996d00c91e0a5de8d9 (diff) | |
parent | cfca06d7963fa0909f90483b42a6d7d194d01e08 (diff) | |
download | src-5ffd83dbcc34f10e07f6d3e968ae6365869615f4.tar.gz src-5ffd83dbcc34f10e07f6d3e968ae6365869615f4.zip |
Merge llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp
master 2e10b7a39b9, the last commit before the llvmorg-12-init tag, from
which release/11.x was branched.
Note that for now, I rolled back all our local changes to make merging
easier, and I will reapply the still-relevant ones after updating to
11.0.0-rc1.
Notes
Notes:
svn path=/projects/clang1100-import/; revision=363742
Diffstat (limited to 'contrib/llvm-project/lldb/source/Utility/ConstString.cpp')
-rw-r--r-- | contrib/llvm-project/lldb/source/Utility/ConstString.cpp | 48 |
1 files changed, 44 insertions, 4 deletions
diff --git a/contrib/llvm-project/lldb/source/Utility/ConstString.cpp b/contrib/llvm-project/lldb/source/Utility/ConstString.cpp index e90bb929bb81..62f79b3df7a5 100644 --- a/contrib/llvm-project/lldb/source/Utility/ConstString.cpp +++ b/contrib/llvm-project/lldb/source/Utility/ConstString.cpp @@ -1,4 +1,4 @@ -//===-- ConstString.cpp -----------------------------------------*- C++ -*-===// +//===-- ConstString.cpp ---------------------------------------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. @@ -29,9 +29,37 @@ using namespace lldb_private; class Pool { public: + /// The default BumpPtrAllocatorImpl slab size. + static const size_t AllocatorSlabSize = 4096; + static const size_t SizeThreshold = AllocatorSlabSize; + /// Every Pool has its own allocator which receives an equal share of + /// the ConstString allocations. This means that when allocating many + /// ConstStrings, every allocator sees only its small share of allocations and + /// assumes LLDB only allocated a small amount of memory so far. In reality + /// LLDB allocated a total memory that is N times as large as what the + /// allocator sees (where N is the number of string pools). This causes that + /// the BumpPtrAllocator continues a long time to allocate memory in small + /// chunks which only makes sense when allocating a small amount of memory + /// (which is true from the perspective of a single allocator). On some + /// systems doing all these small memory allocations causes LLDB to spend + /// a lot of time in malloc, so we need to force all these allocators to + /// behave like one allocator in terms of scaling their memory allocations + /// with increased demand. To do this we set the growth delay for each single + /// allocator to a rate so that our pool of allocators scales their memory + /// allocations similar to a single BumpPtrAllocatorImpl. + /// + /// Currently we have 256 string pools and the normal growth delay of the + /// BumpPtrAllocatorImpl is 128 (i.e., the memory allocation size increases + /// every 128 full chunks), so by changing the delay to 1 we get a + /// total growth delay in our allocator collection of 256/1 = 256. This is + /// still only half as fast as a normal allocator but we can't go any faster + /// without decreasing the number of string pools. + static const size_t AllocatorGrowthDelay = 1; + typedef llvm::BumpPtrAllocatorImpl<llvm::MallocAllocator, AllocatorSlabSize, + SizeThreshold, AllocatorGrowthDelay> + Allocator; typedef const char *StringPoolValueType; - typedef llvm::StringMap<StringPoolValueType, llvm::BumpPtrAllocator> - StringPool; + typedef llvm::StringMap<StringPoolValueType, Allocator> StringPool; typedef llvm::StringMapEntry<StringPoolValueType> StringPoolEntryType; static StringPoolEntryType & @@ -307,5 +335,17 @@ size_t ConstString::StaticMemorySize() { void llvm::format_provider<ConstString>::format(const ConstString &CS, llvm::raw_ostream &OS, llvm::StringRef Options) { - format_provider<StringRef>::format(CS.AsCString(), OS, Options); + format_provider<StringRef>::format(CS.GetStringRef(), OS, Options); +} + +void llvm::yaml::ScalarTraits<ConstString>::output(const ConstString &Val, + void *, raw_ostream &Out) { + Out << Val.GetStringRef(); +} + +llvm::StringRef +llvm::yaml::ScalarTraits<ConstString>::input(llvm::StringRef Scalar, void *, + ConstString &Val) { + Val = ConstString(Scalar); + return {}; } |