[llvm] r341659 - [DebugInfo] Handle stack slot offsets for spilled sub-registers in LDV
David Stenberg via llvm-commits
llvm-commits at lists.llvm.org
Fri Sep 7 06:54:07 PDT 2018
Author: dstenb
Date: Fri Sep 7 06:54:07 2018
New Revision: 341659
URL: http://llvm.org/viewvc/llvm-project?rev=341659&view=rev
Log:
[DebugInfo] Handle stack slot offsets for spilled sub-registers in LDV
Summary:
Extend LDV so that stack slot offsets for spilled sub-registers
are added to the emitted debug locations. This is accomplished
by querying InstrInfo::getStackSlotRange().
With this change, LDV will add a DW_OP_plus_uconst operation to
the expression if a sub-register is spilled. Later on, PEI will
add an offset operation for the stack slot, meaning that we will
get expressions of the forms:
* {DW_OP_constu #fp-offset, DW_OP_minus,
DW_OP_plus_uconst #subreg-offset}
* {DW_OP_plus_const #fp-offset,
DW_OP_minus, DW_OP_plus_uconst #subreg-offset}
The two offset operations should ideally be merged.
Reviewers: rnk, aprantl, stoklund
Reviewed By: aprantl
Subscribers: dblaikie, bjope, nemanjai, JDevlieghere, llvm-commits
Tags: #debug-info
Differential Revision: https://reviews.llvm.org/D51612
Added:
llvm/trunk/test/DebugInfo/PowerPC/live-debug-vars-subreg-offset.ll
Modified:
llvm/trunk/lib/CodeGen/LiveDebugVariables.cpp
Modified: llvm/trunk/lib/CodeGen/LiveDebugVariables.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveDebugVariables.cpp?rev=341659&r1=341658&r2=341659&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveDebugVariables.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveDebugVariables.cpp Fri Sep 7 06:54:07 2018
@@ -135,6 +135,10 @@ private:
/// LocMap - Map of where a user value is live, and its location.
using LocMap = IntervalMap<SlotIndex, DbgValueLocation, 4>;
+/// SpillOffsetMap - Map of stack slot offsets for spilled locations.
+/// Non-spilled locations are not added to the map.
+using SpillOffsetMap = DenseMap<unsigned, unsigned>;
+
namespace {
class LDVImpl;
@@ -168,8 +172,8 @@ class UserValue {
/// insertDebugValue - Insert a DBG_VALUE into MBB at Idx for LocNo.
void insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
- SlotIndex StopIdx,
- DbgValueLocation Loc, bool Spilled, LiveIntervals &LIS,
+ SlotIndex StopIdx, DbgValueLocation Loc, bool Spilled,
+ unsigned SpillOffset, LiveIntervals &LIS,
const TargetInstrInfo &TII,
const TargetRegisterInfo &TRI);
@@ -311,15 +315,18 @@ public:
LiveIntervals &LIS);
/// rewriteLocations - Rewrite virtual register locations according to the
- /// provided virtual register map. Record which locations were spilled.
- void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI,
- BitVector &SpilledLocations);
+ /// provided virtual register map. Record the stack slot offsets for the
+ /// locations that were spilled.
+ void rewriteLocations(VirtRegMap &VRM, const MachineFunction &MF,
+ const TargetInstrInfo &TII,
+ const TargetRegisterInfo &TRI,
+ SpillOffsetMap &SpillOffsets);
/// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
void emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
const TargetInstrInfo &TII,
const TargetRegisterInfo &TRI,
- const BitVector &SpilledLocations);
+ const SpillOffsetMap &SpillOffsets);
/// getDebugLoc - Return DebugLoc of this UserValue.
DebugLoc getDebugLoc() { return dl;}
@@ -1052,8 +1059,10 @@ splitRegister(unsigned OldReg, ArrayRef<
static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
}
-void UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI,
- BitVector &SpilledLocations) {
+void UserValue::rewriteLocations(VirtRegMap &VRM, const MachineFunction &MF,
+ const TargetInstrInfo &TII,
+ const TargetRegisterInfo &TRI,
+ SpillOffsetMap &SpillOffsets) {
// Build a set of new locations with new numbers so we can coalesce our
// IntervalMap if two vreg intervals collapse to the same physical location.
// Use MapVector instead of SetVector because MapVector::insert returns the
@@ -1062,10 +1071,11 @@ void UserValue::rewriteLocations(VirtReg
// FIXME: This will be problematic if we ever support direct and indirect
// frame index locations, i.e. expressing both variables in memory and
// 'int x, *px = &x'. The "spilled" bit must become part of the location.
- MapVector<MachineOperand, bool> NewLocations;
+ MapVector<MachineOperand, std::pair<bool, unsigned>> NewLocations;
SmallVector<unsigned, 4> LocNoMap(locations.size());
for (unsigned I = 0, E = locations.size(); I != E; ++I) {
bool Spilled = false;
+ unsigned SpillOffset = 0;
MachineOperand Loc = locations[I];
// Only virtual registers are rewritten.
if (Loc.isReg() && Loc.getReg() &&
@@ -1078,7 +1088,16 @@ void UserValue::rewriteLocations(VirtReg
// non-existent sub-register, and %noreg is exactly what we want.
Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
} else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
- // FIXME: Translate SubIdx to a stackslot offset.
+ // Retrieve the stack slot offset.
+ unsigned SpillSize;
+ const MachineRegisterInfo &MRI = MF.getRegInfo();
+ const TargetRegisterClass *TRC = MRI.getRegClass(VirtReg);
+ bool Success = TII.getStackSlotRange(TRC, Loc.getSubReg(), SpillSize,
+ SpillOffset, MF);
+
+ // FIXME: Invalidate the location if the offset couldn't be calculated.
+ (void)Success;
+
Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
Spilled = true;
} else {
@@ -1089,20 +1108,22 @@ void UserValue::rewriteLocations(VirtReg
// Insert this location if it doesn't already exist and record a mapping
// from the old number to the new number.
- auto InsertResult = NewLocations.insert({Loc, Spilled});
+ auto InsertResult = NewLocations.insert({Loc, {Spilled, SpillOffset}});
unsigned NewLocNo = std::distance(NewLocations.begin(), InsertResult.first);
LocNoMap[I] = NewLocNo;
}
- // Rewrite the locations and record which ones were spill slots.
+ // Rewrite the locations and record the stack slot offsets for spills.
locations.clear();
- SpilledLocations.clear();
- SpilledLocations.resize(NewLocations.size());
+ SpillOffsets.clear();
for (auto &Pair : NewLocations) {
+ bool Spilled;
+ unsigned SpillOffset;
+ std::tie(Spilled, SpillOffset) = Pair.second;
locations.push_back(Pair.first);
- if (Pair.second) {
+ if (Spilled) {
unsigned NewLocNo = std::distance(&*NewLocations.begin(), &Pair);
- SpilledLocations.set(NewLocNo);
+ SpillOffsets[NewLocNo] = SpillOffset;
}
}
@@ -1171,10 +1192,9 @@ findNextInsertLocation(MachineBasicBlock
}
void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
- SlotIndex StopIdx,
- DbgValueLocation Loc, bool Spilled,
- LiveIntervals &LIS,
- const TargetInstrInfo &TII,
+ SlotIndex StopIdx, DbgValueLocation Loc,
+ bool Spilled, unsigned SpillOffset,
+ LiveIntervals &LIS, const TargetInstrInfo &TII,
const TargetRegisterInfo &TRI) {
SlotIndex MBBEndIdx = LIS.getMBBEndIdx(&*MBB);
// Only search within the current MBB.
@@ -1197,12 +1217,14 @@ void UserValue::insertDebugValue(Machine
// If the location was spilled, the new DBG_VALUE will be indirect. If the
// original DBG_VALUE was indirect, we need to add DW_OP_deref to indicate
- // that the original virtual register was a pointer.
+ // that the original virtual register was a pointer. Also, add the stack slot
+ // offset for the spilled register to the expression.
const DIExpression *Expr = Expression;
bool IsIndirect = Loc.wasIndirect();
if (Spilled) {
- if (IsIndirect)
- Expr = DIExpression::prepend(Expr, DIExpression::WithDeref);
+ auto Deref = IsIndirect ? DIExpression::WithDeref : DIExpression::NoDeref;
+ Expr =
+ DIExpression::prepend(Expr, DIExpression::NoDeref, SpillOffset, Deref);
IsIndirect = true;
}
@@ -1221,14 +1243,17 @@ void UserValue::insertDebugValue(Machine
void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
const TargetInstrInfo &TII,
const TargetRegisterInfo &TRI,
- const BitVector &SpilledLocations) {
+ const SpillOffsetMap &SpillOffsets) {
MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
SlotIndex Start = I.start();
SlotIndex Stop = I.stop();
DbgValueLocation Loc = I.value();
- bool Spilled = !Loc.isUndef() ? SpilledLocations.test(Loc.locNo()) : false;
+ auto SpillIt =
+ !Loc.isUndef() ? SpillOffsets.find(Loc.locNo()) : SpillOffsets.end();
+ bool Spilled = SpillIt != SpillOffsets.end();
+ unsigned SpillOffset = Spilled ? SpillIt->second : 0;
// If the interval start was trimmed to the lexical scope insert the
// DBG_VALUE at the previous index (otherwise it appears after the
@@ -1241,7 +1266,8 @@ void UserValue::emitDebugValues(VirtRegM
SlotIndex MBBEnd = LIS.getMBBEndIdx(&*MBB);
LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd);
- insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, LIS, TII, TRI);
+ insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, SpillOffset, LIS, TII,
+ TRI);
// This interval may span multiple basic blocks.
// Insert a DBG_VALUE into each one.
while (Stop > MBBEnd) {
@@ -1251,7 +1277,8 @@ void UserValue::emitDebugValues(VirtRegM
break;
MBBEnd = LIS.getMBBEndIdx(&*MBB);
LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd);
- insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, LIS, TII, TRI);
+ insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, SpillOffset, LIS, TII,
+ TRI);
}
LLVM_DEBUG(dbgs() << '\n');
if (MBB == MFEnd)
@@ -1266,11 +1293,11 @@ void LDVImpl::emitDebugValues(VirtRegMap
if (!MF)
return;
const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
- BitVector SpilledLocations;
+ SpillOffsetMap SpillOffsets;
for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
LLVM_DEBUG(userValues[i]->print(dbgs(), TRI));
- userValues[i]->rewriteLocations(*VRM, *TRI, SpilledLocations);
- userValues[i]->emitDebugValues(VRM, *LIS, *TII, *TRI, SpilledLocations);
+ userValues[i]->rewriteLocations(*VRM, *MF, *TII, *TRI, SpillOffsets);
+ userValues[i]->emitDebugValues(VRM, *LIS, *TII, *TRI, SpillOffsets);
}
EmitDone = true;
}
Added: llvm/trunk/test/DebugInfo/PowerPC/live-debug-vars-subreg-offset.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/PowerPC/live-debug-vars-subreg-offset.ll?rev=341659&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/PowerPC/live-debug-vars-subreg-offset.ll (added)
+++ llvm/trunk/test/DebugInfo/PowerPC/live-debug-vars-subreg-offset.ll Fri Sep 7 06:54:07 2018
@@ -0,0 +1,81 @@
+; RUN: llc -O3 -stop-after virtregrewriter %s -o - | FileCheck %s
+
+target datalayout = "E-m:e-i64:64-n32:64"
+target triple = "ppc64"
+
+; Verify that live-debug-variables includes the stack slot offset
+; for the sub-register in the debug expression for `spilled'.
+
+; This reproducer was generated from the following C file:
+;
+; extern int foo(void);
+; extern void bar(int);
+;
+; int main() {
+; int spilled = foo();
+;
+; // Clobber all GPRs.
+; __asm volatile ("" : : : "0", "1", "2", "3", "4", "5", "6", "7",
+; "8", "9", "10", "11", "12", "13", "14", "15",
+; "16", "17", "18", "19", "20", "21", "22", "23",
+; "24", "25", "26", "27", "28", "29", "30", "31");
+;
+; for(;;)
+; bar(spilled);
+;
+; return 0;
+; }
+;
+; compiled using:
+;
+; clang --target=ppc64 -O3 -g -S -emit-llvm
+
+; CHECK: ![[VAR:.*]] = !DILocalVariable(name: "spilled"
+
+; CHECK: STD $x3, 0, %stack.0
+; CHECK-NEXT: DBG_VALUE %stack.0, 0, ![[VAR]], !DIExpression(DW_OP_plus_uconst, 4)
+
+; Function Attrs: noreturn nounwind
+define signext i32 @main() local_unnamed_addr #0 !dbg !8 {
+entry:
+ %call = tail call signext i32 @foo() #2, !dbg !14
+ call void @llvm.dbg.value(metadata i32 %call, metadata !13, metadata !DIExpression()), !dbg !14
+ tail call void asm sideeffect "", "~{r0},~{r1},~{r2},~{r3},~{r4},~{r5},~{r6},~{r7},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15},~{r16},~{r17},~{r18},~{r19},~{r20},~{r21},~{r22},~{r23},~{r24},~{r25},~{r26},~{r27},~{r28},~{r29},~{r30},~{r31}"() #2, !dbg !14, !srcloc !15
+ br label %for.cond, !dbg !14
+
+for.cond: ; preds = %for.cond, %entry
+ tail call void @bar(i32 signext %call) #2, !dbg !14
+ br label %for.cond, !dbg !14
+}
+
+declare signext i32 @foo() local_unnamed_addr
+
+declare void @bar(i32 signext) local_unnamed_addr
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.value(metadata, metadata, metadata) #1
+
+attributes #0 = { noreturn nounwind }
+attributes #1 = { nounwind readnone speculatable }
+attributes #2 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+!llvm.ident = !{!7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 8.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "live-debug-vars-subreg-offset.c", directory: "/")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!7 = !{!"clang version 8.0.0"}
+!8 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 4, type: !9, isLocal: false, isDefinition: true, scopeLine: 4, isOptimized: true, unit: !0, retainedNodes: !12)
+!9 = !DISubroutineType(types: !10)
+!10 = !{!11}
+!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!12 = !{!13}
+!13 = !DILocalVariable(name: "spilled", scope: !8, file: !1, line: 5, type: !11)
+!14 = !DILocation(line: 5, column: 17, scope: !8)
+!15 = !{i32 125}
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