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DLAHelpers: relax assumptions on ExtractValueInst

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Before this commit, the DLA code made very strong assumptions about
Functions that returned struct types.
In particular, calls to such Functions were expected to have at most a
number of uses equal to the number of fields of the returned struct.
Moreover, such uses were only expected to be ExtractValueInst.

Now, we still assume that such uses are ExtractValueInst, but we don't
make any strong assumption on their number anymore.

This makes the DLA code less reliant on specific form of LLVM IR, so we
can also drop -gvn-hoist from the decompilation test pipeline.
This commit is contained in:
Pietro Fezzardi
2021-01-05 00:15:55 +01:00
parent 56fe5c95c3
commit 2485cd2c8b
5 changed files with 93 additions and 43 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/Decompiler/DLATypeSystem.cpp
+62 -19
View File
@@ -299,17 +299,38 @@ LayoutTypeSystem::getLayoutTypes(const Value &V) {
}
} else if (auto *StructTy = dyn_cast<StructType>(VTy)) {
revng_assert(not isa<LoadInst>(V));
SmallVector<const Value *, 2> LeafVals;
if (auto *Ins = dyn_cast<InsertValueInst>(&V))
LeafVals = getInsertValueLeafOperands(Ins);
else if (auto *Call = dyn_cast<CallInst>(&V))
LeafVals = getExtractedValuesFromCall(Call);
else
LeafVals.resize(StructTy->getNumElements(), nullptr);
if (auto *Call = dyn_cast<CallInst>(&V)) {
for (const Value *LeafVal : LeafVals)
Results.push_back(getLayoutType(LeafVal));
auto ExtractedValues = getExtractedValuesFromCall(Call);
for (const auto &ExtractedSet : ExtractedValues) {
// Inside here we're working on a single field of the struct.
// ExtractedSet contains all the ExtractValueInst that extract the same
// field of the struct.
// We get or create a layout type for each of them, but they should all
// be the same.
SmallVector<LayoutTypeSystemNode *, 2> FieldResults;
for (const llvm::ExtractValueInst *E : ExtractedSet) {
FieldResults.push_back(getLayoutType(E));
revng_assert(FieldResults.front() == FieldResults.back());
}
Results.push_back(std::move(FieldResults.front()));
}
} else {
SmallVector<const Value *, 2> LeafVals;
if (auto *Ins = dyn_cast<InsertValueInst>(&V))
LeafVals = getInsertValueLeafOperands(Ins);
else
LeafVals.resize(StructTy->getNumElements(), nullptr);
for (const Value *LeafVal : LeafVals)
Results.push_back(getLayoutType(LeafVal));
}
} else {
// For non-struct and non-function types we only add a LayoutTypeSystemNode
Results.push_back(getLayoutType(&V));
@@ -320,7 +341,8 @@ LayoutTypeSystem::getLayoutTypes(const Value &V) {
SmallVector<std::pair<LayoutTypeSystemNode *, bool>, 2>
LayoutTypeSystem::getOrCreateLayoutTypes(const Value &V) {
assertGetLayoutTypePreConditions(V);
SmallVector<std::pair<LayoutTypeSystemNode *, bool>, 2> Results;
using GetOrCreateResult = std::pair<LayoutTypeSystemNode *, bool>;
SmallVector<GetOrCreateResult, 2> Results;
const Type *VTy = V.getType();
if (const auto *F = dyn_cast<Function>(&V)) {
auto *RetTy = F->getReturnType();
@@ -338,17 +360,38 @@ LayoutTypeSystem::getOrCreateLayoutTypes(const Value &V) {
}
} else if (auto *StructTy = dyn_cast<StructType>(VTy)) {
revng_assert(not isa<LoadInst>(V));
SmallVector<const Value *, 2> LeafVals;
if (auto *Ins = dyn_cast<InsertValueInst>(&V))
LeafVals = getInsertValueLeafOperands(Ins);
else if (auto *Call = dyn_cast<CallInst>(&V))
LeafVals = getExtractedValuesFromCall(Call);
else
LeafVals.resize(StructTy->getNumElements(), nullptr);
if (auto *Call = dyn_cast<CallInst>(&V)) {
for (const Value *LeafVal : LeafVals)
Results.push_back(getOrCreateLayoutType(LeafVal));
const auto &ExtractedValues = getExtractedValuesFromCall(Call);
for (const auto &ExtractedSet : ExtractedValues) {
// Inside here we're working on a single field of the struct.
// ExtractedSet contains all the ExtractValueInst that extract the same
// field of the struct.
// We get or create a layout type for each of them, but they should all
// be the same.
SmallVector<GetOrCreateResult, 2> FieldResults;
for (const llvm::ExtractValueInst *E : ExtractedSet) {
FieldResults.push_back(getOrCreateLayoutType(E));
revng_assert(FieldResults.front().first == FieldResults.back().first);
}
Results.push_back(std::move(FieldResults.front()));
}
} else {
SmallVector<const Value *, 2> LeafVals;
if (auto *Ins = dyn_cast<InsertValueInst>(&V))
LeafVals = getInsertValueLeafOperands(Ins);
else
LeafVals.resize(StructTy->getNumElements(), nullptr);
for (const Value *LeafVal : LeafVals)
Results.push_back(getOrCreateLayoutType(LeafVal));
}
} else {
// For non-struct and non-function types we only add a LayoutTypeSystemNode
Results.push_back(getOrCreateLayoutType(&V));