/// Finds the llvm.dbg.declare intrinsic corresponding to an alloca, if any.
DbgDeclareInst *FindAllocaDbgDeclare(Value *V);
-/// Finds the llvm.dbg.value intrinsics describing a value and invoke \p Action
-/// on it.
-void findDbgValues(Value *V, std::function<void(DbgValueInst &)> Action);
-
-/// Constants for \p replaceDbgDeclare and friends.
-enum { NoDeref = false, WithDeref = true };
+/// Finds the llvm.dbg.value intrinsics describing a value, if any.
+void findDbgValues(SmallVectorImpl<DbgValueInst *> &DbgValues, Value *V);
/// Replaces llvm.dbg.declare instruction when the address it describes
/// is replaced with a new value. If Deref is true, an additional DW_OP_deref is
void replaceDbgValueForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
DIBuilder &Builder, int Offset = 0);
-/// Assuming the instruction \p I is going to be deleted, attempt to salvage any
-/// dbg.value intrinsics referring to \p I by rewriting its effect into a
-/// DIExpression.
-void salvageDebugInfo(Instruction &I);
-
/// Remove all instructions from a basic block other than it's terminator
/// and any present EH pad instructions.
unsigned removeAllNonTerminatorAndEHPadInstructions(BasicBlock *BB);
#include "llvm/IR/PatternMatch.h"
#include "llvm/Pass.h"
#include "llvm/Transforms/InstCombine/InstCombineWorklist.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Support/Dwarf.h"
-#include "llvm/IR/DIBuilder.h"
#define DEBUG_TYPE "instcombine"
/// methods should return the value returned by this function.
Instruction *eraseInstFromFunction(Instruction &I) {
DEBUG(dbgs() << "IC: ERASE " << I << '\n');
- assert(I.use_empty() && "Cannot erase instruction that is used!");
- salvageDebugInfo(I);
+ assert(I.use_empty() && "Cannot erase instruction that is used!");
// Make sure that we reprocess all operands now that we reduced their
// use counts.
if (I.getNumOperands() < 8) {
// Since we can't guarantee that the original dbg.declare instrinsic
// is removed by LowerDbgDeclare(), we need to make sure that we are
// not inserting the same dbg.value intrinsic over and over.
- bool Found = false;
- findDbgValues(APN, [&](DbgValueInst &DVI) {
- assert(DVI.getValue() == APN);
- assert(DVI.getOffset() == 0);
- if ((DVI.getVariable() == DIVar) && (DVI.getExpression() == DIExpr))
- Found = true;
- });
- return Found;
+ SmallVector<DbgValueInst *, 1> DbgValues;
+ findDbgValues(DbgValues, APN);
+ for (auto *DVI : DbgValues) {
+ assert(DVI->getValue() == APN);
+ assert(DVI->getOffset() == 0);
+ if ((DVI->getVariable() == DIVar) && (DVI->getExpression() == DIExpr))
+ return true;
+ }
+ return false;
}
/// Inserts a llvm.dbg.value intrinsic before a store to an alloca'd value
return nullptr;
}
-void llvm::findDbgValues(Value *V, std::function<void(DbgValueInst &)> Action) {
+void llvm::findDbgValues(SmallVectorImpl<DbgValueInst *> &DbgValues, Value *V) {
if (auto *L = LocalAsMetadata::getIfExists(V))
if (auto *MDV = MetadataAsValue::getIfExists(V->getContext(), L))
for (User *U : MDV->users())
if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(U))
- Action(*DVI);
+ DbgValues.push_back(DVI);
+}
+
+static void DIExprAddDeref(SmallVectorImpl<uint64_t> &Expr) {
+ Expr.push_back(dwarf::DW_OP_deref);
}
-static void appendOffset(SmallVectorImpl<uint64_t> &Ops, int64_t Offset) {
+static void DIExprAddOffset(SmallVectorImpl<uint64_t> &Expr, int Offset) {
if (Offset > 0) {
- Ops.push_back(dwarf::DW_OP_plus);
- Ops.push_back(Offset);
+ Expr.push_back(dwarf::DW_OP_plus);
+ Expr.push_back(Offset);
} else if (Offset < 0) {
- Ops.push_back(dwarf::DW_OP_minus);
- Ops.push_back(-Offset);
+ Expr.push_back(dwarf::DW_OP_minus);
+ Expr.push_back(-Offset);
}
}
-/// Prepend \p DIExpr with a deref and offset operation.
-static DIExpression *prependDIExpr(DIBuilder &Builder, DIExpression *DIExpr,
- bool Deref, int64_t Offset) {
+static DIExpression *BuildReplacementDIExpr(DIBuilder &Builder,
+ DIExpression *DIExpr, bool Deref,
+ int Offset) {
if (!Deref && !Offset)
return DIExpr;
// Create a copy of the original DIDescriptor for user variable, prepending
// "deref" operation to a list of address elements, as new llvm.dbg.declare
// will take a value storing address of the memory for variable, not
// alloca itself.
- SmallVector<uint64_t, 4> Ops;
+ SmallVector<uint64_t, 4> NewDIExpr;
if (Deref)
- Ops.push_back(dwarf::DW_OP_deref);
- appendOffset(Ops, Offset);
+ DIExprAddDeref(NewDIExpr);
+ DIExprAddOffset(NewDIExpr, Offset);
if (DIExpr)
- Ops.append(DIExpr->elements_begin(), DIExpr->elements_end());
- return Builder.createExpression(Ops);
+ NewDIExpr.append(DIExpr->elements_begin(), DIExpr->elements_end());
+ return Builder.createExpression(NewDIExpr);
}
bool llvm::replaceDbgDeclare(Value *Address, Value *NewAddress,
auto *DIExpr = DDI->getExpression();
assert(DIVar && "Missing variable");
- DIExpr = prependDIExpr(Builder, DIExpr, Deref, Offset);
+ DIExpr = BuildReplacementDIExpr(Builder, DIExpr, Deref, Offset);
// Insert llvm.dbg.declare immediately after the original alloca, and remove
// old llvm.dbg.declare.
// Insert the offset immediately after the first deref.
// We could just change the offset argument of dbg.value, but it's unsigned...
if (Offset) {
- SmallVector<uint64_t, 4> Ops;
- Ops.push_back(dwarf::DW_OP_deref);
- appendOffset(Ops, Offset);
- Ops.append(DIExpr->elements_begin() + 1, DIExpr->elements_end());
- DIExpr = Builder.createExpression(Ops);
+ SmallVector<uint64_t, 4> NewDIExpr;
+ DIExprAddDeref(NewDIExpr);
+ DIExprAddOffset(NewDIExpr, Offset);
+ NewDIExpr.append(DIExpr->elements_begin() + 1, DIExpr->elements_end());
+ DIExpr = Builder.createExpression(NewDIExpr);
}
Builder.insertDbgValueIntrinsic(NewAddress, DVI->getOffset(), DIVar, DIExpr,
}
}
-void llvm::salvageDebugInfo(Instruction &I) {
- auto MDWrap = [&](Value *V) {
- return MetadataAsValue::get(I.getContext(), ValueAsMetadata::get(V));
- };
- auto &M = *I.getModule();
- if (auto *BitCast = dyn_cast<BitCastInst>(&I))
- findDbgValues(BitCast, [&](DbgValueInst &DVI) {
- // Bitcasts are entirely irrelevant for debug info. Rewrite the dbg.value
- // to use the cast's source.
- DVI.setOperand(0, MDWrap(I.getOperand(0)));
- DEBUG(dbgs() << "SALVAGE: " << DVI << '\n');
- });
- else if (auto *GEP = dyn_cast<GetElementPtrInst>(&I))
- findDbgValues(GEP, [&](DbgValueInst &DVI) {
- unsigned BitWidth =
- M.getDataLayout().getPointerSizeInBits(GEP->getPointerAddressSpace());
- APInt Offset(BitWidth, 0);
- // Rewrite a constant GEP into a DIExpression.
- if (GEP->accumulateConstantOffset(M.getDataLayout(), Offset)) {
- auto *DIExpr = DVI.getExpression();
- DIBuilder DIB(M, /*AllowUnresolved*/ false);
- // GEP offsets are i32 and thus alwaus fit into an int64_t.
- DIExpr = prependDIExpr(DIB, DIExpr, NoDeref, Offset.getSExtValue());
- DVI.setOperand(0, MDWrap(I.getOperand(0)));
- DVI.setOperand(3, MetadataAsValue::get(I.getContext(), DIExpr));
- DEBUG(dbgs() << "SALVAGE: " << DVI << '\n');
- }
- });
- else if (auto *Load = dyn_cast<LoadInst>(&I))
- findDbgValues(Load, [&](DbgValueInst &DVI) {
- // Rewrite the load into DW_OP_deref.
- auto *DIExpr = DVI.getExpression();
- DIBuilder DIB(M, /*AllowUnresolved*/ false);
- DIExpr = prependDIExpr(DIB, DIExpr, WithDeref, 0);
- DVI.setOperand(0, MDWrap(I.getOperand(0)));
- DVI.setOperand(3, MetadataAsValue::get(I.getContext(), DIExpr));
- DEBUG(dbgs() << "SALVAGE: " << DVI << '\n');
- });
-}
-
unsigned llvm::removeAllNonTerminatorAndEHPadInstructions(BasicBlock *BB) {
unsigned NumDeadInst = 0;
// Delete the instructions backwards, as it has a reduced likelihood of
+++ /dev/null
-; RUN: opt -instcombine %s -S -o - | FileCheck %s
-; Verify that the eliminated instructions (bitcast, gep, load) are salvaged into
-; a DIExpression.
-;
-; Originally created from the following C source and then heavily isolated/reduced.
-;
-; struct entry {
-; struct entry *next;
-; };
-; void scan(struct entry *queue, struct entry *end)
-; {
-; struct entry *entry;
-; for (entry = (struct entry *)((char *)(queue->next) - 8);
-; &entry->next == end;
-; entry = (struct entry *)((char *)(entry->next) - 8)) {
-; }
-; }
-
-; ModuleID = '<stdin>'
-source_filename = "test.c"
-target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
-target triple = "x86_64-apple-macosx10.12.0"
-
-%struct.entry = type { %struct.entry* }
-
-; Function Attrs: nounwind ssp uwtable
-define void @salvage_load(%struct.entry** %queue) local_unnamed_addr #0 !dbg !14 {
-entry:
- %im_not_dead = alloca %struct.entry*
- %0 = load %struct.entry*, %struct.entry** %queue, align 8, !dbg !19
- %1 = load %struct.entry*, %struct.entry** %queue, align 8, !dbg !19
- call void @llvm.dbg.value(metadata %struct.entry* %1, i64 0, metadata !18, metadata !20), !dbg !19
-; CHECK: define void @salvage_load
-; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @llvm.dbg.value(metadata %struct.entry** %queue, i64 0,
-; CHECK-SAME: metadata ![[LOAD_EXPR:[0-9]+]])
- store %struct.entry* %1, %struct.entry** %im_not_dead, align 8
- ret void, !dbg !21
-}
-
-; Function Attrs: nounwind ssp uwtable
-define void @salvage_bitcast(%struct.entry* %queue) local_unnamed_addr #0 !dbg !14 {
-entry:
- %im_not_dead = alloca i8*
- %0 = bitcast %struct.entry* %queue to i8*, !dbg !19
- %1 = bitcast %struct.entry* %queue to i8*, !dbg !19
- call void @llvm.dbg.value(metadata i8* %1, i64 0, metadata !18, metadata !20), !dbg !19
-; CHECK: define void @salvage_bitcast
-; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @llvm.dbg.value(metadata %struct.entry* %queue, i64 0,
-; CHECK-SAME: metadata ![[BITCAST_EXPR:[0-9]+]])
- store i8* %1, i8** %im_not_dead, align 8
- ret void, !dbg !21
-}
-
-; Function Attrs: nounwind ssp uwtable
-define void @salvage_gep(%struct.entry* %queue, %struct.entry* %end) local_unnamed_addr #0 !dbg !14 {
-entry:
- %im_not_dead = alloca %struct.entry**
- %0 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !19
- %1 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !19
- call void @llvm.dbg.value(metadata %struct.entry** %1, i64 0, metadata !18, metadata !20), !dbg !19
-; CHECK: define void @salvage_gep
-; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @llvm.dbg.value(metadata %struct.entry* %queue, i64 0,
-; CHECK-SAME: metadata ![[GEP_EXPR:[0-9]+]])
- store %struct.entry** %1, %struct.entry*** %im_not_dead, align 8
- ret void, !dbg !21
-}
-
-; CHECK: ![[LOAD_EXPR]] = !DIExpression(DW_OP_deref, DW_OP_plus, 0)
-; CHECK: ![[BITCAST_EXPR]] = !DIExpression(DW_OP_plus, 0)
-; CHECK: ![[GEP_EXPR]] = !DIExpression(DW_OP_minus, 8, DW_OP_plus, 0)
-
-; Function Attrs: nounwind readnone
-declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1
-
-attributes #0 = { nounwind ssp uwtable }
-attributes #1 = { nounwind readnone }
-
-!llvm.dbg.cu = !{!0}
-!llvm.module.flags = !{!10, !11, !12}
-!llvm.ident = !{!13}
-
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 5.0.0 (trunk 297628) (llvm/trunk 297643)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3)
-!1 = !DIFile(filename: "test.c", directory: "/")
-!2 = !{}
-!3 = !{!4, !8}
-!4 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !5, size: 64)
-!5 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "entry", file: !1, line: 1, size: 64, elements: !6)
-!6 = !{!7}
-!7 = !DIDerivedType(tag: DW_TAG_member, name: "next", scope: !5, file: !1, line: 2, baseType: !4, size: 64)
-!8 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !9, size: 64)
-!9 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
-!10 = !{i32 2, !"Dwarf Version", i32 4}
-!11 = !{i32 2, !"Debug Info Version", i32 3}
-!12 = !{i32 1, !"PIC Level", i32 2}
-!13 = !{!"clang version 5.0.0 (trunk 297628) (llvm/trunk 297643)"}
-!14 = distinct !DISubprogram(name: "scan", scope: !1, file: !1, line: 4, type: !15, isLocal: false, isDefinition: true, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !17)
-!15 = !DISubroutineType(types: !16)
-!16 = !{null, !4, !4}
-!17 = !{!18}
-!18 = !DILocalVariable(name: "entry", scope: !14, file: !1, line: 6, type: !4)
-!19 = !DILocation(line: 6, column: 17, scope: !14)
-!20 = !DIExpression(DW_OP_plus, 0)
-!21 = !DILocation(line: 11, column: 1, scope: !14)