Author: Jeremy Morse Date: 2022-02-07T13:26:38-08:00 New Revision: 762c17b7b6f24a55b4071382f822114128bb3af1
URL: https://github.com/llvm/llvm-project/commit/762c17b7b6f24a55b4071382f822114128bb3af1 DIFF: https://github.com/llvm/llvm-project/commit/762c17b7b6f24a55b4071382f822114128bb3af1.diff LOG: [DebugInfo][InstrRef][NFC] Free resources at an earlier stage This patch releases some memory from InstrRefBasedLDV earlier that it would otherwise. The underlying problem is: * We store a big table of "live in values for each block", * We translate that into DBG_VALUE instructions in each block, And both exist in memory at the same time, which needlessly doubles that information. The most of what this patch does is: as we progressively translate live-in information into DBG_VALUEs, we free the variable-value / machine-value tracking information as we go, which significantly reduces peak memory. While I'm here, also add a clear method to wipe variable assignments that have been accumulated into VLocTracker objects, and turn a DenseMap into a SmallDenseMap to avoid an initial allocation. Differential Revision: https://reviews.llvm.org/D118453 (cherry picked from commit a80181a81ea44215e49e5da1457614ec0bd44111) Added: Modified: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h Removed: ################################################################################ diff --git a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp index 25d764dee2ed8..7b06bc9b0c39c 100644 --- a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp +++ b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp @@ -1029,7 +1029,7 @@ bool InstrRefBasedLDV::transferDebugInstrRef(MachineInstr &MI, // Only handle this instruction when we are building the variable value // transfer function. - if (!VTracker) + if (!VTracker && !TTracker) return false; unsigned InstNo = MI.getOperand(0).getImm(); @@ -1185,7 +1185,8 @@ bool InstrRefBasedLDV::transferDebugInstrRef(MachineInstr &MI, // for DBG_INSTR_REFs as DBG_VALUEs (just, the former can refer to values that // aren't immediately available). DbgValueProperties Properties(Expr, false); - VTracker->defVar(MI, Properties, NewID); + if (VTracker) + VTracker->defVar(MI, Properties, NewID); // If we're on the final pass through the function, decompose this INSTR_REF // into a plain DBG_VALUE. @@ -2826,6 +2827,7 @@ void InstrRefBasedLDV::emitLocations( const TargetPassConfig &TPC) { TTracker = new TransferTracker(TII, MTracker, MF, *TRI, CalleeSavedRegs, TPC); unsigned NumLocs = MTracker->getNumLocs(); + VTracker = nullptr; // For each block, load in the machine value locations and variable value // live-ins, then step through each instruction in the block. New DBG_VALUEs @@ -2844,6 +2846,15 @@ void InstrRefBasedLDV::emitLocations( TTracker->checkInstForNewValues(CurInst, MI.getIterator()); ++CurInst; } + + // Our block information has now been converted into DBG_VALUEs, to be + // inserted below. Free the memory we allocated to track variable / register + // values. If we don't, we needlessy record the same info in memory twice. + delete[] MInLocs[bbnum]; + delete[] MOutLocs[bbnum]; + MInLocs[bbnum] = nullptr; + MOutLocs[bbnum] = nullptr; + SavedLiveIns[bbnum].clear(); } emitTransfers(AllVarsNumbering); @@ -3080,6 +3091,12 @@ bool InstrRefBasedLDV::ExtendRanges(MachineFunction &MF, << " has " << MaxNumBlocks << " basic blocks and " << VarAssignCount << " variable assignments, exceeding limits.\n"); + + // Perform memory cleanup that emitLocations would do otherwise. + for (int Idx = 0; Idx < MaxNumBlocks; ++Idx) { + delete[] MOutLocs[Idx]; + delete[] MInLocs[Idx]; + } } else { // Compute the extended ranges, iterating over scopes. There might be // something to be said for ordering them by size/locality, but that's for @@ -3091,6 +3108,9 @@ bool InstrRefBasedLDV::ExtendRanges(MachineFunction &MF, vlocs); } + // Now that we've analysed variable assignments, free any tracking data. + vlocs.clear(); + // Using the computed value locations and variable values for each block, // create the DBG_VALUE instructions representing the extended variable // locations. @@ -3100,11 +3120,7 @@ bool InstrRefBasedLDV::ExtendRanges(MachineFunction &MF, Changed = TTracker->Transfers.size() != 0; } - // Common clean-up of memory. - for (int Idx = 0; Idx < MaxNumBlocks; ++Idx) { - delete[] MOutLocs[Idx]; - delete[] MInLocs[Idx]; - } + // Elements of these arrays will be deleted by emitLocations. delete[] MOutLocs; delete[] MInLocs; diff --git a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h index 1e1bb758d3d44..9ae0d4dd087c3 100644 --- a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h +++ b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h @@ -680,7 +680,7 @@ class VLocTracker { /// movement of values between locations inside of a block is handled at a /// much later stage, in the TransferTracker class. MapVector<DebugVariable, DbgValue> Vars; - DenseMap<DebugVariable, const DILocation *> Scopes; + SmallDenseMap<DebugVariable, const DILocation *, 8> Scopes; MachineBasicBlock *MBB = nullptr; const OverlapMap &OverlappingFragments; DbgValueProperties EmptyProperties; @@ -749,6 +749,11 @@ class VLocTracker { Scopes[Overlapped] = Loc; } } + + void clear() { + Vars.clear(); + Scopes.clear(); + } }; // XXX XXX docs _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
