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-rw-r--r--lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp97
1 files changed, 59 insertions, 38 deletions
diff --git a/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp b/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
index a66d08e..0c2a5e5 100644
--- a/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
+++ b/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
@@ -8,25 +8,25 @@
//===----------------------------------------------------------------------===//
#include "DbgValueHistoryCalculator.h"
+#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/IR/DebugInfo.h"
#include "llvm/Support/Debug.h"
#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.
static unsigned isDescribedByReg(const MachineInstr &MI) {
assert(MI.isDebugValue());
- assert(MI.getNumOperands() == 3);
+ assert(MI.getNumOperands() == 4);
// If location of variable is described using a register (directly or
// indirecltly), this register is always a first operand.
return MI.getOperand(0).isReg() ? MI.getOperand(0).getReg() : 0;
@@ -36,7 +36,7 @@ void DbgValueHistoryMap::startInstrRange(const MDNode *Var,
const MachineInstr &MI) {
// Instruction range should start with a DBG_VALUE instruction for the
// variable.
- assert(MI.isDebugValue() && MI.getDebugVariable() == Var);
+ assert(MI.isDebugValue() && "not a DBG_VALUE");
auto &Ranges = VarInstrRanges[Var];
if (!Ranges.empty() && Ranges.back().second == nullptr &&
Ranges.back().first->isIdenticalTo(&MI)) {
@@ -96,6 +96,19 @@ static void addRegDescribedVar(RegDescribedVarsMap &RegVars,
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,
@@ -104,22 +117,26 @@ static void clobberRegisterUses(RegDescribedVarsMap &RegVars, unsigned RegNo,
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 insert them to @Regs.
-static void collectClobberedRegisters(const MachineInstr &MI,
+// \brief Collect all registers clobbered by @MI and apply the functor
+// @Func to their RegNo.
+// @Func should be a functor with a void(unsigned) signature. We're
+// not using std::function here for performance reasons. It has a
+// small but measurable impact. By using a functor instead of a
+// std::set& here, we can avoid the overhead of constructing
+// temporaries in calculateDbgValueHistory, which has a significant
+// performance impact.
+template<typename Callable>
+static void applyToClobberedRegisters(const MachineInstr &MI,
const TargetRegisterInfo *TRI,
- std::set<unsigned> &Regs) {
+ Callable Func) {
for (const MachineOperand &MO : MI.operands()) {
if (!MO.isReg() || !MO.isDef() || !MO.getReg())
continue;
for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid(); ++AI)
- Regs.insert(*AI);
+ Func(*AI);
}
}
@@ -133,11 +150,12 @@ static const MachineInstr *getFirstEpilogueInst(const MachineBasicBlock &MBB) {
// 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.
@@ -145,25 +163,26 @@ static const MachineInstr *getFirstEpilogueInst(const MachineBasicBlock &MBB) {
}
// \brief Collect registers that are modified in the function body (their
-// contents is changed only in the prologue and epilogue).
+// 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);
- bool IsInEpilogue = false;
+
for (const auto &MI : MBB) {
- IsInEpilogue |= &MI == FirstEpilogueInst;
- if (!MI.getFlag(MachineInstr::FrameSetup) && !IsInEpilogue)
- collectClobberedRegisters(MI, TRI, Regs);
+ if (&MI == FirstEpilogueInst)
+ break;
+ if (!MI.getFlag(MachineInstr::FrameSetup))
+ 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;
@@ -172,17 +191,18 @@ void calculateDbgValueHistory(const MachineFunction *MF,
if (!MI.isDebugValue()) {
// Not a DBG_VALUE instruction. It may clobber registers which describe
// some variables.
- std::set<unsigned> MIClobberedRegs;
- collectClobberedRegisters(MI, TRI, MIClobberedRegs);
- for (unsigned RegNo : MIClobberedRegs) {
- if (ChangingRegs.count(RegNo))
+ applyToClobberedRegisters(MI, TRI, [&](unsigned RegNo) {
+ if (ChangingRegs.test(RegNo))
clobberRegisterUses(RegVars, RegNo, Result, MI);
- }
+ });
continue;
}
assert(MI.getNumOperands() > 1 && "Invalid DBG_VALUE instruction!");
- const MDNode *Var = MI.getDebugVariable();
+ // Use the base variable (without any DW_OP_piece expressions)
+ // as index into History. The full variables including the
+ // piece expressions are attached to the MI.
+ DIVariable Var = MI.getDebugVariable();
if (unsigned PrevReg = Result.getRegisterForVar(Var))
dropRegDescribedVar(RegVars, PrevReg, Var);
@@ -196,11 +216,12 @@ void calculateDbgValueHistory(const MachineFunction *MF,
// 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());
+ }
}
}
}
-
-}
generated by cgit v1.1 at 2024-12-22 14:58:21 +0000