================
@@ -2876,42 +2875,101 @@ void AsmPrinter::emitJumpTableInfo() {
MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference64,
F);
+
+ std::vector<unsigned> JumpTableIndices;
+ if (!TM.Options.EnableStaticDataPartitioning) {
+ for (unsigned JTI = 0, JTSize = JT.size(); JTI < JTSize; ++JTI)
+ JumpTableIndices.push_back(JTI);
+ emitJumpTables(JumpTableIndices, TLOF.getSectionForJumpTable(F, TM),
+ JTInDiffSection, *MJTI);
+ return;
+ }
+
+ // When static data partitioning is enabled, collect jump table entries that
+ // go into the same section together to reduce the amount of section switch
+ // statements.
+ //
+ // Iterate all jump tables, put hot jump table indices towards the beginning
+ // of the vector, and cold jump table indices towards the end. Meanwhile
+ // retain the relative orders of original jump tables within a hot or
unlikely
+ // section by reversing the cold jump table indices.
+ int NextHotJumpTableIndex = 0, NextColdJumpTableIndex = JT.size() - 1;
+ JumpTableIndices.resize(JT.size());
+ for (unsigned JTI = 0, JTSize = JT.size(); JTI < JTSize; ++JTI) {
+ if (JT[JTI].Hotness == MachineFunctionDataHotness::Cold)
+ JumpTableIndices[NextColdJumpTableIndex--] = JTI;
+ else
+ JumpTableIndices[NextHotJumpTableIndex++] = JTI;
+ }
+
+ if (NextHotJumpTableIndex != 0) {
+ emitJumpTables(
+ ArrayRef<unsigned>(JumpTableIndices).take_front(NextHotJumpTableIndex),
+ TLOF.getSectionForJumpTable(F, TM, &JT[0]), JTInDiffSection, *MJTI);
+ }
+
+ if (NextHotJumpTableIndex < (int)JT.size()) {
+ // Reverse the order of cold jump tables indices.
+ for (int L = NextHotJumpTableIndex, R = JT.size() - 1; L < R; ++L, --R)
+ std::swap(JumpTableIndices[L], JumpTableIndices[R]);
----------------
mingmingl-llvm wrote:
This makes sense to not update memory and I like the idea of reverse iterating.
I ended up using `llvm::make_range` to specify the iterated range and order,
and templated the original `emitJumpTables` method. I also renamed it to
`emitJumpTableImpl` and removed `virtual` keyword from it.
https://github.com/llvm/llvm-project/pull/122215
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