[llvm] r219123 - DbgValueHistoryCalculator: Store modified registers in a BitVector instead of std::set.
Benjamin Kramer
benny.kra at googlemail.com
Mon Oct 6 08:31:04 PDT 2014
Author: d0k
Date: Mon Oct 6 10:31:04 2014
New Revision: 219123
URL: http://llvm.org/viewvc/llvm-project?rev=219123&view=rev
Log:
DbgValueHistoryCalculator: Store modified registers in a BitVector instead of std::set.
And iterate over the smaller map instead of the larger set first. Reduces the time spent in
calculateDbgValueHistory by 30-40%.
Modified:
llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp?rev=219123&r1=219122&r2=219123&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp Mon Oct 6 10:31:04 2014
@@ -8,6 +8,7 @@
//===----------------------------------------------------------------------===//
#include "DbgValueHistoryCalculator.h"
+#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
@@ -16,12 +17,10 @@
#include "llvm/Target/TargetRegisterInfo.h"
#include <algorithm>
#include <map>
-#include <set>
+using namespace llvm;
#define DEBUG_TYPE "dwarfdebug"
-namespace llvm {
-
// \brief If @MI is a DBG_VALUE with debug value described by a
// defined register, returns the number of this register.
// In the other case, returns 0.
@@ -97,6 +96,19 @@ static void addRegDescribedVar(RegDescri
VarSet.push_back(Var);
}
+// \brief Terminate the location range for variables described by register at
+// @I by inserting @ClobberingInstr to their history.
+static void clobberRegisterUses(RegDescribedVarsMap &RegVars,
+ RegDescribedVarsMap::iterator I,
+ DbgValueHistoryMap &HistMap,
+ const MachineInstr &ClobberingInstr) {
+ // Iterate over all variables described by this register and add this
+ // instruction to their history, clobbering it.
+ for (const auto &Var : I->second)
+ HistMap.endInstrRange(Var, ClobberingInstr);
+ RegVars.erase(I);
+}
+
// \brief Terminate the location range for variables described by register
// @RegNo by inserting @ClobberingInstr to their history.
static void clobberRegisterUses(RegDescribedVarsMap &RegVars, unsigned RegNo,
@@ -105,11 +117,7 @@ static void clobberRegisterUses(RegDescr
const auto &I = RegVars.find(RegNo);
if (I == RegVars.end())
return;
- // Iterate over all variables described by this register and add this
- // instruction to their history, clobbering it.
- for (const auto &Var : I->second)
- HistMap.endInstrRange(Var, ClobberingInstr);
- RegVars.erase(I);
+ clobberRegisterUses(RegVars, I, HistMap, ClobberingInstr);
}
// \brief Collect all registers clobbered by @MI and apply the functor
@@ -142,11 +150,12 @@ static const MachineInstr *getFirstEpilo
// as the return instruction.
DebugLoc LastLoc = LastMI->getDebugLoc();
auto Res = LastMI;
- for (MachineBasicBlock::const_reverse_iterator I(std::next(LastMI)); I != MBB.rend();
- ++I) {
+ for (MachineBasicBlock::const_reverse_iterator I(std::next(LastMI)),
+ E = MBB.rend();
+ I != E; ++I) {
if (I->getDebugLoc() != LastLoc)
return Res;
- Res = std::prev(I.base());
+ Res = &*I;
}
// If all instructions have the same debug location, assume whole MBB is
// an epilogue.
@@ -157,7 +166,7 @@ static const MachineInstr *getFirstEpilo
// contents is changed outside of the prologue and epilogue).
static void collectChangingRegs(const MachineFunction *MF,
const TargetRegisterInfo *TRI,
- std::set<unsigned> &Regs) {
+ BitVector &Regs) {
for (const auto &MBB : *MF) {
auto FirstEpilogueInst = getFirstEpilogueInst(MBB);
@@ -165,15 +174,15 @@ static void collectChangingRegs(const Ma
if (&MI == FirstEpilogueInst)
break;
if (!MI.getFlag(MachineInstr::FrameSetup))
- applyToClobberedRegisters(MI, TRI, [&](unsigned r) { Regs.insert(r); });
+ applyToClobberedRegisters(MI, TRI, [&](unsigned r) { Regs.set(r); });
}
}
}
-void calculateDbgValueHistory(const MachineFunction *MF,
- const TargetRegisterInfo *TRI,
- DbgValueHistoryMap &Result) {
- std::set<unsigned> ChangingRegs;
+void llvm::calculateDbgValueHistory(const MachineFunction *MF,
+ const TargetRegisterInfo *TRI,
+ DbgValueHistoryMap &Result) {
+ BitVector ChangingRegs(TRI->getNumRegs());
collectChangingRegs(MF, TRI, ChangingRegs);
RegDescribedVarsMap RegVars;
@@ -183,7 +192,7 @@ void calculateDbgValueHistory(const Mach
// Not a DBG_VALUE instruction. It may clobber registers which describe
// some variables.
applyToClobberedRegisters(MI, TRI, [&](unsigned RegNo) {
- if (ChangingRegs.count(RegNo))
+ if (ChangingRegs.test(RegNo))
clobberRegisterUses(RegVars, RegNo, Result, MI);
});
continue;
@@ -207,11 +216,12 @@ void calculateDbgValueHistory(const Mach
// Make sure locations for register-described variables are valid only
// until the end of the basic block (unless it's the last basic block, in
// which case let their liveness run off to the end of the function).
- if (!MBB.empty() && &MBB != &MF->back()) {
- for (unsigned RegNo : ChangingRegs)
- clobberRegisterUses(RegVars, RegNo, Result, MBB.back());
+ if (!MBB.empty() && &MBB != &MF->back()) {
+ for (auto I = RegVars.begin(), E = RegVars.end(); I != E;) {
+ auto CurElem = I++; // CurElem can be erased below.
+ if (ChangingRegs.test(CurElem->first))
+ clobberRegisterUses(RegVars, CurElem, Result, MBB.back());
+ }
}
}
}
-
-}
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