<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Oct 6, 2014 at 8:31 AM, Benjamin Kramer <span dir="ltr"><<a href="mailto:benny.kra@googlemail.com" target="_blank">benny.kra@googlemail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: d0k<br>
Date: Mon Oct 6 10:31:04 2014<br>
New Revision: 219123<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=219123&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=219123&view=rev</a><br>
Log:<br>
DbgValueHistoryCalculator: Store modified registers in a BitVector instead of std::set.<br>
<br>
And iterate over the smaller map instead of the larger set first. Reduces the time spent in<br>
calculateDbgValueHistory by 30-40%.<br></blockquote><div><br></div><div>Awesome - thanks a bunch.<br><br>Any particular tool/approach you took in finding this?</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Modified:<br>
llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp<br>
<br>
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp?rev=219123&r1=219122&r2=219123&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp?rev=219123&r1=219122&r2=219123&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp (original)<br>
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp Mon Oct 6 10:31:04 2014<br>
@@ -8,6 +8,7 @@<br>
//===----------------------------------------------------------------------===//<br>
<br>
#include "DbgValueHistoryCalculator.h"<br>
+#include "llvm/ADT/BitVector.h"<br>
#include "llvm/ADT/SmallVector.h"<br>
#include "llvm/CodeGen/MachineBasicBlock.h"<br>
#include "llvm/CodeGen/MachineFunction.h"<br>
@@ -16,12 +17,10 @@<br>
#include "llvm/Target/TargetRegisterInfo.h"<br>
#include <algorithm><br>
#include <map><br>
-#include <set><br>
+using namespace llvm;<br>
<br>
#define DEBUG_TYPE "dwarfdebug"<br>
<br>
-namespace llvm {<br>
-<br>
// \brief If @MI is a DBG_VALUE with debug value described by a<br>
// defined register, returns the number of this register.<br>
// In the other case, returns 0.<br>
@@ -97,6 +96,19 @@ static void addRegDescribedVar(RegDescri<br>
VarSet.push_back(Var);<br>
}<br>
<br>
+// \brief Terminate the location range for variables described by register at<br>
+// @I by inserting @ClobberingInstr to their history.<br>
+static void clobberRegisterUses(RegDescribedVarsMap &RegVars,<br>
+ RegDescribedVarsMap::iterator I,<br>
+ DbgValueHistoryMap &HistMap,<br>
+ const MachineInstr &ClobberingInstr) {<br>
+ // Iterate over all variables described by this register and add this<br>
+ // instruction to their history, clobbering it.<br>
+ for (const auto &Var : I->second)<br>
+ HistMap.endInstrRange(Var, ClobberingInstr);<br>
+ RegVars.erase(I);<br>
+}<br>
+<br>
// \brief Terminate the location range for variables described by register<br>
// @RegNo by inserting @ClobberingInstr to their history.<br>
static void clobberRegisterUses(RegDescribedVarsMap &RegVars, unsigned RegNo,<br>
@@ -105,11 +117,7 @@ static void clobberRegisterUses(RegDescr<br>
const auto &I = RegVars.find(RegNo);<br>
if (I == RegVars.end())<br>
return;<br>
- // Iterate over all variables described by this register and add this<br>
- // instruction to their history, clobbering it.<br>
- for (const auto &Var : I->second)<br>
- HistMap.endInstrRange(Var, ClobberingInstr);<br>
- RegVars.erase(I);<br>
+ clobberRegisterUses(RegVars, I, HistMap, ClobberingInstr);<br>
}<br>
<br>
// \brief Collect all registers clobbered by @MI and apply the functor<br>
@@ -142,11 +150,12 @@ static const MachineInstr *getFirstEpilo<br>
// as the return instruction.<br>
DebugLoc LastLoc = LastMI->getDebugLoc();<br>
auto Res = LastMI;<br>
- for (MachineBasicBlock::const_reverse_iterator I(std::next(LastMI)); I != MBB.rend();<br>
- ++I) {<br>
+ for (MachineBasicBlock::const_reverse_iterator I(std::next(LastMI)),<br>
+ E = MBB.rend();<br>
+ I != E; ++I) {<br>
if (I->getDebugLoc() != LastLoc)<br>
return Res;<br>
- Res = std::prev(I.base());<br>
+ Res = &*I;<br>
}<br>
// If all instructions have the same debug location, assume whole MBB is<br>
// an epilogue.<br>
@@ -157,7 +166,7 @@ static const MachineInstr *getFirstEpilo<br>
// contents is changed outside of the prologue and epilogue).<br>
static void collectChangingRegs(const MachineFunction *MF,<br>
const TargetRegisterInfo *TRI,<br>
- std::set<unsigned> &Regs) {<br>
+ BitVector &Regs) {<br>
for (const auto &MBB : *MF) {<br>
auto FirstEpilogueInst = getFirstEpilogueInst(MBB);<br>
<br>
@@ -165,15 +174,15 @@ static void collectChangingRegs(const Ma<br>
if (&MI == FirstEpilogueInst)<br>
break;<br>
if (!MI.getFlag(MachineInstr::FrameSetup))<br>
- applyToClobberedRegisters(MI, TRI, [&](unsigned r) { Regs.insert(r); });<br>
+ applyToClobberedRegisters(MI, TRI, [&](unsigned r) { Regs.set(r); });<br>
}<br>
}<br>
}<br>
<br>
-void calculateDbgValueHistory(const MachineFunction *MF,<br>
- const TargetRegisterInfo *TRI,<br>
- DbgValueHistoryMap &Result) {<br>
- std::set<unsigned> ChangingRegs;<br>
+void llvm::calculateDbgValueHistory(const MachineFunction *MF,<br>
+ const TargetRegisterInfo *TRI,<br>
+ DbgValueHistoryMap &Result) {<br>
+ BitVector ChangingRegs(TRI->getNumRegs());<br>
collectChangingRegs(MF, TRI, ChangingRegs);<br>
<br>
RegDescribedVarsMap RegVars;<br>
@@ -183,7 +192,7 @@ void calculateDbgValueHistory(const Mach<br>
// Not a DBG_VALUE instruction. It may clobber registers which describe<br>
// some variables.<br>
applyToClobberedRegisters(MI, TRI, [&](unsigned RegNo) {<br>
- if (ChangingRegs.count(RegNo))<br>
+ if (ChangingRegs.test(RegNo))<br>
clobberRegisterUses(RegVars, RegNo, Result, MI);<br>
});<br>
continue;<br>
@@ -207,11 +216,12 @@ void calculateDbgValueHistory(const Mach<br>
// Make sure locations for register-described variables are valid only<br>
// until the end of the basic block (unless it's the last basic block, in<br>
// which case let their liveness run off to the end of the function).<br>
- if (!MBB.empty() && &MBB != &MF->back()) {<br>
- for (unsigned RegNo : ChangingRegs)<br>
- clobberRegisterUses(RegVars, RegNo, Result, MBB.back());<br>
+ if (!MBB.empty() && &MBB != &MF->back()) {<br>
+ for (auto I = RegVars.begin(), E = RegVars.end(); I != E;) {<br>
+ auto CurElem = I++; // CurElem can be erased below.<br>
+ if (ChangingRegs.test(CurElem->first))<br>
+ clobberRegisterUses(RegVars, CurElem, Result, MBB.back());<br>
+ }<br>
}<br>
}<br>
}<br>
-<br>
-}<br>
<br>
<br>
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</blockquote></div><br></div></div>