LLVM 19.0.0git
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AssignmentTrackingAnalysis.cpp File Reference
#include "llvm/CodeGen/AssignmentTrackingAnalysis.h"
#include "LiveDebugValues/LiveDebugValues.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/IntervalMap.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/UniqueVector.h"
#include "llvm/Analysis/Interval.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DebugProgramInstruction.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/PrintPasses.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include <assert.h>
#include <cstdint>
#include <optional>
#include <queue>
#include <sstream>
#include <unordered_map>

Go to the source code of this file.

Classes

struct  llvm::DenseMapInfo< VariableID >
 
struct  std::hash< VarLocInsertPt >
 
class  FunctionVarLocsBuilder
 Helper class to build FunctionVarLocs, since that class isn't easy to modify. More...
 

Namespaces

namespace  std
 Implement std::hash so that hash_code can be used in STL containers.
 

Macros

#define DEBUG_TYPE   "debug-ata"
 

Typedefs

using VarLocInsertPt = PointerUnion< const Instruction *, const DbgRecord * >
 
using DebugAggregate = std::pair< const DILocalVariable *, const DILocation * >
 A whole (unfragmented) source variable.
 

Functions

 STATISTIC (NumDefsScanned, "Number of dbg locs that get scanned for removal")
 
 STATISTIC (NumDefsRemoved, "Number of dbg locs removed")
 
 STATISTIC (NumWedgesScanned, "Number of dbg wedges scanned")
 
 STATISTIC (NumWedgesChanged, "Number of dbg wedges changed")
 
static std::pair< Value *, DIExpression * > walkToAllocaAndPrependOffsetDeref (const DataLayout &DL, Value *Start, DIExpression *Expression)
 Walk backwards along constant GEPs and bitcasts to the base storage from Start as far as possible.
 
static std::optional< int64_t > getDerefOffsetInBytes (const DIExpression *DIExpr)
 Extract the offset used in DIExpr.
 
static DebugAggregate getAggregate (const DbgVariableIntrinsic *DII)
 
static DebugAggregate getAggregate (const DebugVariable &Var)
 
static bool shouldCoalesceFragments (Function &F)
 
static DIAssignIDgetIDFromInst (const Instruction &I)
 
static DIAssignIDgetIDFromMarker (const DbgAssignIntrinsic &DAI)
 
static DIAssignIDgetIDFromMarker (const DPValue &DPV)
 
const charlocStr (AssignmentTrackingLowering::LocKind Loc)
 
VarLocInsertPt getNextNode (const DbgRecord *DPV)
 
VarLocInsertPt getNextNode (const Instruction *Inst)
 
VarLocInsertPt getNextNode (VarLocInsertPt InsertPt)
 
DbgAssignIntrinsicCastToDbgAssign (DbgVariableIntrinsic *DVI)
 
DPValueCastToDbgAssign (DPValue *DPV)
 
template<typename T >
static bool hasZeroSizedFragment (T &DbgValue)
 
static bool fullyContains (DIExpression::FragmentInfo A, DIExpression::FragmentInfo B)
 Return true if A fully contains B.
 
static std::optional< at::AssignmentInfogetUntaggedStoreAssignmentInfo (const Instruction &I, const DataLayout &Layout)
 
DbgDeclareInstDynCastToDbgDeclare (DbgVariableIntrinsic *DVI)
 
DPValueDynCastToDbgDeclare (DPValue *DPV)
 
static AssignmentTrackingLowering::OverlapMap buildOverlapMapAndRecordDeclares (Function &Fn, FunctionVarLocsBuilder *FnVarLocs, const DenseSet< DebugAggregate > &VarsWithStackSlot, AssignmentTrackingLowering::UntaggedStoreAssignmentMap &UntaggedStoreVars, unsigned &TrackedVariablesVectorSize)
 Build a map of {Variable x: Variables y} where all variable fragments contained within the variable fragment x are in set y.
 
static bool removeRedundantDbgLocsUsingBackwardScan (const BasicBlock *BB, FunctionVarLocsBuilder &FnVarLocs)
 Remove redundant definitions within sequences of consecutive location defs.
 
static bool removeRedundantDbgLocsUsingForwardScan (const BasicBlock *BB, FunctionVarLocsBuilder &FnVarLocs)
 Remove redundant location defs using a forward scan.
 
static bool removeUndefDbgLocsFromEntryBlock (const BasicBlock *BB, FunctionVarLocsBuilder &FnVarLocs)
 
static bool removeRedundantDbgLocs (const BasicBlock *BB, FunctionVarLocsBuilder &FnVarLocs)
 
static DenseSet< DebugAggregatefindVarsWithStackSlot (Function &Fn)
 
static void analyzeFunction (Function &Fn, const DataLayout &Layout, FunctionVarLocsBuilder *FnVarLocs)
 

Variables

static cl::opt< unsignedMaxNumBlocks ("debug-ata-max-blocks", cl::init(10000), cl::desc("Maximum num basic blocks before debug info dropped"), cl::Hidden)
 
static cl::opt< boolEnableMemLocFragFill ("mem-loc-frag-fill", cl::init(true), cl::Hidden)
 Option for debugging the pass, determines if the memory location fragment filling happens after generating the variable locations.
 
static cl::opt< boolPrintResults ("print-debug-ata", cl::init(false), cl::Hidden)
 Print the results of the analysis. Respects -filter-print-funcs.
 
static cl::opt< cl::boolOrDefaultCoalesceAdjacentFragmentsOpt ("debug-ata-coalesce-frags", cl::Hidden)
 Coalesce adjacent dbg locs describing memory locations that have contiguous fragments.
 

Macro Definition Documentation

◆ DEBUG_TYPE

#define DEBUG_TYPE   "debug-ata"

Definition at line 42 of file AssignmentTrackingAnalysis.cpp.

Typedef Documentation

◆ DebugAggregate

A whole (unfragmented) source variable.

Definition at line 326 of file AssignmentTrackingAnalysis.cpp.

◆ VarLocInsertPt

Definition at line 85 of file AssignmentTrackingAnalysis.cpp.

Function Documentation

◆ analyzeFunction()

static void analyzeFunction ( Function Fn,
const DataLayout Layout,
FunctionVarLocsBuilder FnVarLocs 
)
static

◆ buildOverlapMapAndRecordDeclares()

static AssignmentTrackingLowering::OverlapMap buildOverlapMapAndRecordDeclares ( Function Fn,
FunctionVarLocsBuilder FnVarLocs,
const DenseSet< DebugAggregate > &  VarsWithStackSlot,
AssignmentTrackingLowering::UntaggedStoreAssignmentMap UntaggedStoreVars,
unsigned TrackedVariablesVectorSize 
)
static

Build a map of {Variable x: Variables y} where all variable fragments contained within the variable fragment x are in set y.

This means that y does not contain all overlaps because partial overlaps are excluded.

While we're iterating over the function, add single location defs for dbg.declares to FnVarLocs.

Variables that are interesting to this pass in are added to FnVarLocs->Variables first. TrackedVariablesVectorSize is set to the ID of the last interesting variable plus 1, meaning variables with ID 1 (inclusive) to TrackedVariablesVectorSize (exclusive) are interesting. The subsequent variables are either stack homed or fully promoted.

Finally, populate UntaggedStoreVars with a mapping of untagged stores to the stored-to variable fragments.

These tasks are bundled together to reduce the number of times we need to iterate over the function as they can be achieved together in one pass.

Definition at line 2147 of file AssignmentTrackingAnalysis.cpp.

References FunctionVarLocsBuilder::addSingleLocVar(), assert(), llvm::SmallVectorTemplateCommon< T, typename >::begin(), llvm::at::calculateFragmentIntersect(), llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::contains(), DynCastToDbgDeclare(), llvm::SmallVectorTemplateCommon< T, typename >::end(), llvm::DPValue::filter(), fullyContains(), llvm::at::getAssignmentMarkers(), llvm::Module::getDataLayout(), llvm::DbgRecord::getDebugLoc(), llvm::at::getDPVAssignmentMarkers(), llvm::DPValue::getExpression(), llvm::DebugVariable::getInlinedAt(), FunctionVarLocsBuilder::getNumVariables(), llvm::GlobalValue::getParent(), llvm::DPValue::getRawLocation(), getUntaggedStoreAssignmentInfo(), llvm::DebugVariable::getVariable(), I, Info, llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::insert(), FunctionVarLocsBuilder::insertVariable(), and llvm::SmallVectorTemplateBase< T, bool >::push_back().

◆ CastToDbgAssign() [1/2]

DbgAssignIntrinsic * CastToDbgAssign ( DbgVariableIntrinsic DVI)

Definition at line 1513 of file AssignmentTrackingAnalysis.cpp.

◆ CastToDbgAssign() [2/2]

DPValue * CastToDbgAssign ( DPValue DPV)

Definition at line 1517 of file AssignmentTrackingAnalysis.cpp.

References assert(), and llvm::DPValue::isDbgAssign().

◆ DynCastToDbgDeclare() [1/2]

DbgDeclareInst * DynCastToDbgDeclare ( DbgVariableIntrinsic DVI)

Definition at line 2121 of file AssignmentTrackingAnalysis.cpp.

Referenced by buildOverlapMapAndRecordDeclares().

◆ DynCastToDbgDeclare() [2/2]

DPValue * DynCastToDbgDeclare ( DPValue DPV)

Definition at line 2125 of file AssignmentTrackingAnalysis.cpp.

References llvm::DPValue::isDbgDeclare().

◆ findVarsWithStackSlot()

static DenseSet< DebugAggregate > findVarsWithStackSlot ( Function Fn)
static

◆ fullyContains()

static bool fullyContains ( DIExpression::FragmentInfo  A,
DIExpression::FragmentInfo  B 
)
static

Return true if A fully contains B.

Definition at line 2094 of file AssignmentTrackingAnalysis.cpp.

References A, and B.

Referenced by buildOverlapMapAndRecordDeclares().

◆ getAggregate() [1/2]

static DebugAggregate getAggregate ( const DbgVariableIntrinsic DII)
static

◆ getAggregate() [2/2]

static DebugAggregate getAggregate ( const DebugVariable Var)
static

◆ getDerefOffsetInBytes()

static std::optional< int64_t > getDerefOffsetInBytes ( const DIExpression DIExpr)
static

Extract the offset used in DIExpr.

Returns std::nullopt if the expression doesn't explicitly describe a memory location with DW_OP_deref or if the expression is too complex to interpret.

Definition at line 284 of file AssignmentTrackingAnalysis.cpp.

References llvm::dwarf::DW_OP_LLVM_fragment, llvm::DIExpression::getElements(), llvm::DIExpression::getNumElements(), and llvm::Offset.

◆ getIDFromInst()

static DIAssignID * getIDFromInst ( const Instruction I)
static

Definition at line 1451 of file AssignmentTrackingAnalysis.cpp.

References I.

◆ getIDFromMarker() [1/2]

static DIAssignID * getIDFromMarker ( const DbgAssignIntrinsic DAI)
static

◆ getIDFromMarker() [2/2]

static DIAssignID * getIDFromMarker ( const DPValue DPV)
static

◆ getNextNode() [1/3]

VarLocInsertPt getNextNode ( const DbgRecord DPV)

◆ getNextNode() [2/3]

VarLocInsertPt getNextNode ( const Instruction Inst)

◆ getNextNode() [3/3]

VarLocInsertPt getNextNode ( VarLocInsertPt  InsertPt)

Definition at line 1507 of file AssignmentTrackingAnalysis.cpp.

References getNextNode().

◆ getUntaggedStoreAssignmentInfo()

static std::optional< at::AssignmentInfo > getUntaggedStoreAssignmentInfo ( const Instruction I,
const DataLayout Layout 
)
static

Definition at line 2109 of file AssignmentTrackingAnalysis.cpp.

References llvm::at::getAssignmentInfo(), I, and MI.

Referenced by buildOverlapMapAndRecordDeclares().

◆ hasZeroSizedFragment()

template<typename T >
static bool hasZeroSizedFragment ( T DbgValue)
static

Definition at line 1841 of file AssignmentTrackingAnalysis.cpp.

References F.

◆ locStr()

const char * locStr ( AssignmentTrackingLowering::LocKind  Loc)

Definition at line 1481 of file AssignmentTrackingAnalysis.cpp.

References llvm_unreachable.

◆ removeRedundantDbgLocs()

static bool removeRedundantDbgLocs ( const BasicBlock BB,
FunctionVarLocsBuilder FnVarLocs 
)
static

◆ removeRedundantDbgLocsUsingBackwardScan()

static bool removeRedundantDbgLocsUsingBackwardScan ( const BasicBlock BB,
FunctionVarLocsBuilder FnVarLocs 
)
static

◆ removeRedundantDbgLocsUsingForwardScan()

static bool removeRedundantDbgLocsUsingForwardScan ( const BasicBlock BB,
FunctionVarLocsBuilder FnVarLocs 
)
static

Remove redundant location defs using a forward scan.

This can remove a location definition that is redundant due to indicating that a variable has the same value as is already being indicated by an earlier def.

This implements removeRedundantDbgInstrsUsingForwardScan from lib/Transforms/Utils/BasicBlockUtils.cpp for locations described with FunctionVarLocsBuilder instead of with intrinsics

Definition at line 2585 of file AssignmentTrackingAnalysis.cpp.

References llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::end(), llvm::DPValue::filter(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::find(), llvm::DebugVariable::getVariable(), FunctionVarLocsBuilder::getVariable(), FunctionVarLocsBuilder::getWedge(), I, llvm::SmallVectorTemplateBase< T, bool >::push_back(), and FunctionVarLocsBuilder::setWedge().

Referenced by removeRedundantDbgLocs().

◆ removeUndefDbgLocsFromEntryBlock()

static bool removeUndefDbgLocsFromEntryBlock ( const BasicBlock BB,
FunctionVarLocsBuilder FnVarLocs 
)
static

◆ shouldCoalesceFragments()

static bool shouldCoalesceFragments ( Function F)
static

◆ STATISTIC() [1/4]

STATISTIC ( NumDefsRemoved  ,
"Number of dbg locs removed"   
)

◆ STATISTIC() [2/4]

STATISTIC ( NumDefsScanned  ,
"Number of dbg locs that get scanned for removal"   
)

◆ STATISTIC() [3/4]

STATISTIC ( NumWedgesChanged  ,
"Number of dbg wedges changed"   
)

◆ STATISTIC() [4/4]

STATISTIC ( NumWedgesScanned  ,
"Number of dbg wedges scanned"   
)

◆ walkToAllocaAndPrependOffsetDeref()

static std::pair< Value *, DIExpression * > walkToAllocaAndPrependOffsetDeref ( const DataLayout DL,
Value Start,
DIExpression Expression 
)
static

Walk backwards along constant GEPs and bitcasts to the base storage from Start as far as possible.

Prepend \Expression with the offset and append it with a DW_OP_deref that haes been implicit until now. Returns the walked-to value and modified expression.

Definition at line 265 of file AssignmentTrackingAnalysis.cpp.

References llvm::DIExpression::append(), DL, End, llvm::APInt::getBoolValue(), llvm::APInt::getZExtValue(), and llvm::DIExpression::prependOpcodes().

Variable Documentation

◆ CoalesceAdjacentFragmentsOpt

cl::opt< cl::boolOrDefault > CoalesceAdjacentFragmentsOpt("debug-ata-coalesce-frags", cl::Hidden) ( "debug-ata-coalesce-frags"  ,
cl::Hidden   
)
static

Coalesce adjacent dbg locs describing memory locations that have contiguous fragments.

This reduces the cost of LiveDebugValues which does SSA construction for each explicitly stated variable fragment.

Referenced by shouldCoalesceFragments().

◆ EnableMemLocFragFill

cl::opt< bool > EnableMemLocFragFill("mem-loc-frag-fill", cl::init(true), cl::Hidden) ( "mem-loc-frag-fill"  ,
cl::init(true ,
cl::Hidden   
)
static

Option for debugging the pass, determines if the memory location fragment filling happens after generating the variable locations.

◆ MaxNumBlocks

cl::opt< unsigned > MaxNumBlocks("debug-ata-max-blocks", cl::init(10000), cl::desc("Maximum num basic blocks before debug info dropped"), cl::Hidden) ( "debug-ata-max-blocks"  ,
cl::init(10000)  ,
cl::desc("Maximum num basic blocks before debug info dropped")  ,
cl::Hidden   
)
static

◆ PrintResults

cl::opt< bool > PrintResults("print-debug-ata", cl::init(false), cl::Hidden) ( "print-debug-ata"  ,
cl::init(false)  ,
cl::Hidden   
)
static

Print the results of the analysis. Respects -filter-print-funcs.

Referenced by llvm::AssignmentTrackingAnalysis::runOnFunction().