[llvm] Introduce DIExpression::foldConstantMath() (PR #71718)
Shubham Sandeep Rastogi via llvm-commits
llvm-commits at lists.llvm.org
Wed Nov 8 10:36:34 PST 2023
https://github.com/rastogishubham created https://github.com/llvm/llvm-project/pull/71718
DIExpressions can get very long and have a lot of redundant operations. This function uses simple pattern matching to fold constant math that can be evaluated at compile time.
The hope is that other people can contribute other patterns as well.
I also couldn't see a good way of combining this with `DIExpression::constantFold` so it stands alone.
This is part of a stack of patches and comes after
https://github.com/llvm/llvm-project/pull/69768
https://github.com/llvm/llvm-project/pull/71717
>From 4f59a7651f4cabc61086f7fc256dd9028962b5b0 Mon Sep 17 00:00:00 2001
From: Shubham Sandeep Rastogi <srastogi22 at apple.com>
Date: Wed, 4 Oct 2023 11:34:19 -0700
Subject: [PATCH 1/3] [NFC] Move DIExpressionCursor to DebugInfoMetadata.h
---
llvm/include/llvm/IR/DebugInfoMetadata.h | 61 +++++++++++++++++++
llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h | 61 -------------------
2 files changed, 61 insertions(+), 61 deletions(-)
diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
index b347664883fd9f2..86ee9f004cfd42b 100644
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -3073,6 +3073,67 @@ template <> struct DenseMapInfo<DIExpression::FragmentInfo> {
static bool isEqual(const FragInfo &A, const FragInfo &B) { return A == B; }
};
+/// Holds a DIExpression and keeps track of how many operands have been consumed
+/// so far.
+class DIExpressionCursor {
+ DIExpression::expr_op_iterator Start, End;
+
+public:
+ DIExpressionCursor(const DIExpression *Expr) {
+ if (!Expr) {
+ assert(Start == End);
+ return;
+ }
+ Start = Expr->expr_op_begin();
+ End = Expr->expr_op_end();
+ }
+
+ DIExpressionCursor(ArrayRef<uint64_t> Expr)
+ : Start(Expr.begin()), End(Expr.end()) {}
+
+ DIExpressionCursor(const DIExpressionCursor &) = default;
+
+ /// Consume one operation.
+ std::optional<DIExpression::ExprOperand> take() {
+ if (Start == End)
+ return std::nullopt;
+ return *(Start++);
+ }
+
+ /// Consume N operations.
+ void consume(unsigned N) { std::advance(Start, N); }
+
+ /// Return the current operation.
+ std::optional<DIExpression::ExprOperand> peek() const {
+ if (Start == End)
+ return std::nullopt;
+ return *(Start);
+ }
+
+ /// Return the next operation.
+ std::optional<DIExpression::ExprOperand> peekNext() const {
+ if (Start == End)
+ return std::nullopt;
+
+ auto Next = Start.getNext();
+ if (Next == End)
+ return std::nullopt;
+
+ return *Next;
+ }
+
+ /// Determine whether there are any operations left in this expression.
+ operator bool() const { return Start != End; }
+
+ DIExpression::expr_op_iterator begin() const { return Start; }
+ DIExpression::expr_op_iterator end() const { return End; }
+
+ /// Retrieve the fragment information, if any.
+ std::optional<DIExpression::FragmentInfo> getFragmentInfo() const {
+ return DIExpression::getFragmentInfo(Start, End);
+ }
+};
+
/// Global variables.
///
/// TODO: Remove DisplayName. It's always equal to Name.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h
index 667a9efc6f6c04f..4daa78b15b8e298 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h
@@ -31,67 +31,6 @@ class DIELoc;
class TargetRegisterInfo;
class MachineLocation;
-/// Holds a DIExpression and keeps track of how many operands have been consumed
-/// so far.
-class DIExpressionCursor {
- DIExpression::expr_op_iterator Start, End;
-
-public:
- DIExpressionCursor(const DIExpression *Expr) {
- if (!Expr) {
- assert(Start == End);
- return;
- }
- Start = Expr->expr_op_begin();
- End = Expr->expr_op_end();
- }
-
- DIExpressionCursor(ArrayRef<uint64_t> Expr)
- : Start(Expr.begin()), End(Expr.end()) {}
-
- DIExpressionCursor(const DIExpressionCursor &) = default;
-
- /// Consume one operation.
- std::optional<DIExpression::ExprOperand> take() {
- if (Start == End)
- return std::nullopt;
- return *(Start++);
- }
-
- /// Consume N operations.
- void consume(unsigned N) { std::advance(Start, N); }
-
- /// Return the current operation.
- std::optional<DIExpression::ExprOperand> peek() const {
- if (Start == End)
- return std::nullopt;
- return *(Start);
- }
-
- /// Return the next operation.
- std::optional<DIExpression::ExprOperand> peekNext() const {
- if (Start == End)
- return std::nullopt;
-
- auto Next = Start.getNext();
- if (Next == End)
- return std::nullopt;
-
- return *Next;
- }
-
- /// Determine whether there are any operations left in this expression.
- operator bool() const { return Start != End; }
-
- DIExpression::expr_op_iterator begin() const { return Start; }
- DIExpression::expr_op_iterator end() const { return End; }
-
- /// Retrieve the fragment information, if any.
- std::optional<DIExpression::FragmentInfo> getFragmentInfo() const {
- return DIExpression::getFragmentInfo(Start, End);
- }
-};
-
/// Base class containing the logic for constructing DWARF expressions
/// independently of whether they are emitted into a DIE or into a .debug_loc
/// entry.
>From dc8229d4ec54bb3b6d77d620c8d16805a2788bf1 Mon Sep 17 00:00:00 2001
From: Shubham Sandeep Rastogi <srastogi22 at apple.com>
Date: Wed, 1 Nov 2023 17:25:26 -0700
Subject: [PATCH 2/3] Add functions peekNextN(unsigned) and
assignNewExpr(ArrayRef<uint64_t>) to DIExpressionCursor
This commit adds two functions to the DIExpressionCursor class.
peekNextN(unsigned) works like peekNext, but lets you peek the next Nth
element
assignNewExpr(ArrayRef<uint64_t>) lets you assign a new expression to
the same DIExpressionCursor object
---
llvm/include/llvm/IR/DebugInfoMetadata.h | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
index 86ee9f004cfd42b..5ea8d853e86c854 100644
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -3044,6 +3044,8 @@ class DIExpression : public MDNode {
/// expression and constant on failure.
std::pair<DIExpression *, const ConstantInt *>
constantFold(const ConstantInt *CI);
+
+ DIExpression *constantFold();
};
inline bool operator==(const DIExpression::FragmentInfo &A,
@@ -3122,6 +3124,25 @@ class DIExpressionCursor {
return *Next;
}
+ std::optional<DIExpression::ExprOperand> peekNextN(unsigned N) const {
+ if (Start == End)
+ return std::nullopt;
+ DIExpression::expr_op_iterator Nth = Start;
+ for (unsigned I = 0; I < N; I++) {
+ Nth = Nth.getNext();
+ if (Nth == End)
+ return std::nullopt;
+ }
+ return *Nth;
+ }
+
+ void assignNewExpr(ArrayRef<uint64_t> Expr) {
+ DIExpression::expr_op_iterator NewStart(Expr.begin());
+ DIExpression::expr_op_iterator NewEnd(Expr.end());
+ this->Start = NewStart;
+ this->End = NewEnd;
+ }
+
/// Determine whether there are any operations left in this expression.
operator bool() const { return Start != End; }
>From 003c0f633fcc6b18870f1ef89ecb5a38c68b5272 Mon Sep 17 00:00:00 2001
From: Shubham Sandeep Rastogi <srastogi22 at apple.com>
Date: Fri, 20 Oct 2023 10:44:22 -0700
Subject: [PATCH 3/3] Introduce DIExpression::foldConstantMath()
DIExpressions can get very long and have a lot of redundant operations.
This function uses simple pattern matching to fold constant math that
can be evaluated at compile time.
---
llvm/include/llvm/IR/DebugInfoMetadata.h | 5 +-
llvm/lib/IR/DebugInfoMetadata.cpp | 281 ++++++++++++++++++++++-
llvm/unittests/IR/MetadataTest.cpp | 277 ++++++++++++++++++++++
3 files changed, 561 insertions(+), 2 deletions(-)
diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
index 5ea8d853e86c854..354ae48c3d676c1 100644
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -3045,7 +3045,10 @@ class DIExpression : public MDNode {
std::pair<DIExpression *, const ConstantInt *>
constantFold(const ConstantInt *CI);
- DIExpression *constantFold();
+ /// Try to shorten an expression with constand math operations that can be
+ /// evaulated at compile time. Returns a new expression on success, or the old
+ /// expression if there is nothing to be reduced.
+ DIExpression *foldConstantMath();
};
inline bool operator==(const DIExpression::FragmentInfo &A,
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index f7f36129ec8557c..b73ffa3880fcc4a 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -1857,7 +1857,6 @@ DIExpression *DIExpression::append(const DIExpression *Expr,
}
Op.appendToVector(NewOps);
}
-
NewOps.append(Ops.begin(), Ops.end());
auto *result = DIExpression::get(Expr->getContext(), NewOps);
assert(result->isValid() && "concatenated expression is not valid");
@@ -1998,6 +1997,286 @@ DIExpression::constantFold(const ConstantInt *CI) {
ConstantInt::get(getContext(), NewInt)};
}
+static bool isConstOperation(uint64_t Op) {
+ return Op == dwarf::DW_OP_constu || Op == dwarf::DW_OP_consts;
+}
+
+static bool operationIsNoOp(uint64_t Op, uint64_t Val) {
+ switch (Op) {
+ case dwarf::DW_OP_plus:
+ case dwarf::DW_OP_minus:
+ case dwarf::DW_OP_shl:
+ case dwarf::DW_OP_shr:
+ return Val == 0;
+ case dwarf::DW_OP_mul:
+ case dwarf::DW_OP_div:
+ return Val == 1;
+ default:
+ return false;
+ }
+}
+
+static std::optional<uint64_t>
+foldOperationIfPossible(uint64_t Op, uint64_t Operand1, uint64_t Operand2) {
+ switch (Op) {
+ case dwarf::DW_OP_plus:
+ return Operand1 + Operand2;
+ case dwarf::DW_OP_minus:
+ return Operand1 - Operand2;
+ case dwarf::DW_OP_shl:
+ return Operand1 << Operand2;
+ case dwarf::DW_OP_shr:
+ return Operand1 >> Operand2;
+ case dwarf::DW_OP_mul:
+ return Operand1 * Operand2;
+ case dwarf::DW_OP_div:
+ return Operand1 / Operand2;
+ default:
+ return std::nullopt;
+ }
+}
+
+static bool operationsAreFoldableAndCommutative(uint64_t Op1, uint64_t Op2) {
+ if (Op1 != Op2)
+ return false;
+ switch (Op1) {
+ case dwarf::DW_OP_plus:
+ case dwarf::DW_OP_mul:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static void moveCursorAndLocPos(DIExpressionCursor &Cursor, uint64_t &Loc,
+ const DIExpression::ExprOperand &Op) {
+ Cursor.consume(1);
+ Loc = Loc + Op.getSize();
+}
+
+DIExpression *DIExpression::foldConstantMath() {
+
+ SmallVector<uint64_t, 8> WorkingOps;
+ WorkingOps.append(Elements.begin(), Elements.end());
+ uint64_t Loc = 0;
+ DIExpressionCursor Cursor(WorkingOps);
+
+ while (Loc < WorkingOps.size()) {
+
+ auto Op1 = Cursor.peek();
+ // Expression has no operations, exit
+ if (!Op1)
+ break;
+ auto Op1Raw = Op1->getOp();
+ auto Op1Arg = Op1->getArg(0);
+
+ // {DW_OP_plus_uconst, 0} -> {}
+ if (Op1Raw == dwarf::DW_OP_plus_uconst && Op1Arg == 0) {
+ WorkingOps.erase(WorkingOps.begin() + Loc, WorkingOps.begin() + Loc + 2);
+ moveCursorAndLocPos(Cursor, Loc, *Op1);
+ continue;
+ }
+
+ if (!isConstOperation(Op1Raw) && Op1Raw != dwarf::DW_OP_plus_uconst) {
+ // Early exit, all of the following patterns start with a constant value
+ moveCursorAndLocPos(Cursor, Loc, *Op1);
+ continue;
+ }
+
+ auto Op2 = Cursor.peekNext();
+ // All following patterns require at least 2 Operations, exit
+ if (!Op2)
+ break;
+ auto Op2Raw = Op2->getOp();
+
+ // {DW_OP_const[u, s], 0, DW_OP_[plus, minus, shl, shr]} -> {}
+ // {DW_OP_const[u, s], 1, DW_OP_[mul, div]} -> {}
+ if (isConstOperation(Op1Raw) && operationIsNoOp(Op2Raw, Op1Arg)) {
+ WorkingOps.erase(WorkingOps.begin() + Loc, WorkingOps.begin() + Loc + 3);
+ Cursor.assignNewExpr(WorkingOps);
+ Loc = 0;
+ continue;
+ }
+
+ auto Op2Arg = Op2->getArg(0);
+
+ // {DW_OP_plus_uconst, Const1, DW_OP_plus_uconst, Const2} ->
+ // {DW_OP_plus_uconst, Const1 + Const2}
+ if (Op1Raw == dwarf::DW_OP_plus_uconst &&
+ Op2Raw == dwarf::DW_OP_plus_uconst) {
+ auto Result = Op1Arg + Op2Arg;
+ WorkingOps.erase(WorkingOps.begin() + Loc + 2,
+ WorkingOps.begin() + Loc + 4);
+ WorkingOps[Loc + 1] = Result;
+ Cursor.assignNewExpr(WorkingOps);
+ Loc = 0;
+ continue;
+ }
+
+ // {DW_OP_const[u, s], Const1, DW_OP_plus_uconst Const2} -> {DW_OP_constu,
+ // Const1 + Const2}
+ if (isConstOperation(Op1Raw) && Op2Raw == dwarf::DW_OP_plus_uconst) {
+ auto Result = Op1Arg + Op2Arg;
+ WorkingOps.erase(WorkingOps.begin() + Loc + 2,
+ WorkingOps.begin() + Loc + 4);
+ WorkingOps[Loc] = dwarf::DW_OP_constu;
+ WorkingOps[Loc + 1] = Result;
+ Cursor.assignNewExpr(WorkingOps);
+ Loc = 0;
+ continue;
+ }
+
+ auto Op3 = Cursor.peekNextN(2);
+ // Op2 could still match a pattern, skip iteration
+ if (!Op3) {
+ moveCursorAndLocPos(Cursor, Loc, *Op1);
+ continue;
+ }
+ auto Op3Raw = Op3->getOp();
+
+ // {DW_OP_const[u, s], Const1, DW_OP_const[u, s], Const2, DW_OP_[plus,
+ // minus, mul, div, shl, shr] -> {DW_OP_constu, Const1 [+, -, *, /, <<, >>]
+ // Const2}
+ if (isConstOperation(Op1Raw) && isConstOperation(Op2Raw)) {
+ auto Result = foldOperationIfPossible(Op3Raw, Op1Arg, Op2Arg);
+ if (!Result) {
+ moveCursorAndLocPos(Cursor, Loc, *Op1);
+ continue;
+ }
+ WorkingOps.erase(WorkingOps.begin() + Loc + 2,
+ WorkingOps.begin() + Loc + 5);
+ WorkingOps[Loc] = dwarf::DW_OP_constu;
+ WorkingOps[Loc + 1] = *Result;
+ Cursor.assignNewExpr(WorkingOps);
+ Loc = 0;
+ continue;
+ }
+
+ // {DW_OP_plus_uconst, Const1, DW_OP_const[u, s], Const1, DW_OP_plus} ->
+ // {DW_OP_plus_uconst, Const1 + Const2}
+ if (Op1Raw == dwarf::DW_OP_plus_uconst && isConstOperation(Op2Raw) &&
+ Op3Raw == dwarf::DW_OP_plus) {
+ auto Result = Op1Arg + Op2Arg;
+ WorkingOps.erase(WorkingOps.begin() + Loc + 2, WorkingOps.begin() + 5);
+ WorkingOps[Loc + 1] = Result;
+ Cursor.assignNewExpr(WorkingOps);
+ Loc = 0;
+ continue;
+ }
+
+ auto Op3Arg = Op3->getArg(0);
+ // {DW_OP_const[u, s], Const1, DW_OP_plus, DW_OP_plus_uconst, Const2} ->
+ // {DW_OP_plus_uconst, Const1 + Const2}
+ if (isConstOperation(Op1Raw) && Op2Raw == dwarf::DW_OP_plus &&
+ Op3Raw == dwarf::DW_OP_plus_uconst) {
+ auto Result = Op1Arg + Op3Arg;
+ WorkingOps.erase(WorkingOps.begin() + Loc + 2, WorkingOps.begin() + 5);
+ WorkingOps[Loc] = dwarf::DW_OP_plus_uconst;
+ WorkingOps[Loc + 1] = Result;
+ Cursor.assignNewExpr(WorkingOps);
+ Loc = 0;
+ continue;
+ }
+
+ auto Op4 = Cursor.peekNextN(3);
+ // Op2 and Op3 could still match a pattern, skip iteration
+ if (!Op4) {
+ moveCursorAndLocPos(Cursor, Loc, *Op1);
+ continue;
+ }
+ auto Op4Raw = Op4->getOp();
+
+ // {DW_OP_const[u, s], Const1, DW_OP_[plus, mul], Const2, DW_OP_[plus, mul]}
+ // -> {DW_OP_constu, Const1 [+, *] Const2, DW_OP_[plus, mul]}
+ if (isConstOperation(Op1Raw) && isConstOperation(Op3Raw) &&
+ operationsAreFoldableAndCommutative(Op2Raw, Op4Raw)) {
+ auto Result = foldOperationIfPossible(Op2Raw, Op1Arg, Op3Arg);
+ if (!Result)
+ llvm_unreachable(
+ "Something went very wrong here! This should always work");
+ WorkingOps.erase(WorkingOps.begin() + Loc + 3,
+ WorkingOps.begin() + Loc + 6);
+ WorkingOps[Loc] = dwarf::DW_OP_constu;
+ WorkingOps[Loc + 1] = *Result;
+ Cursor.assignNewExpr(WorkingOps);
+ Loc = 0;
+ continue;
+ }
+ auto Op5 = Cursor.peekNextN(4);
+ if (!Op5) {
+ moveCursorAndLocPos(Cursor, Loc, *Op1);
+ continue;
+ }
+ auto Op5Raw = Op5->getOp();
+ auto Op5Arg = Op5->getArg(0);
+
+ // {DW_OP_const[u, s], Const1, DW_OP_plus, DW_OP_LLVM_arg, Arg1, DW_OP_plus,
+ // DW_OP_plus_uconst, Const2} -> {DW_OP_constu, Const1 + Const2, DW_OP_plus,
+ // DW_OP_LLVM_arg, Arg1, DW_OP_plus}
+ if (isConstOperation(Op1Raw) && Op3Raw == dwarf::DW_OP_LLVM_arg &&
+ Op5Raw == dwarf::DW_OP_plus_uconst && Op2Raw == Op4Raw &&
+ Op4Raw == dwarf::DW_OP_plus) {
+ auto Result = Op1Arg + Op5Arg;
+ WorkingOps.erase(WorkingOps.begin() + Loc + 6,
+ WorkingOps.begin() + Loc + 8);
+ WorkingOps[Loc] = dwarf::DW_OP_constu;
+ WorkingOps[Loc + 1] = Result;
+ Cursor.assignNewExpr(WorkingOps);
+ Loc = 0;
+ continue;
+ }
+
+ auto Op4Arg = Op4->getArg(0);
+
+ // {DW_OP_plus_uconst, Const1, DW_OP_LLVM_arg, Arg1, DW_OP_plus,
+ // DW_OP_const[u, s], Const2, DW_OP_plus} -> {DW_OP_plus_uconst, Const1 +
+ // Const2, DW_OP_LLVM_arg, Arg1, DW_OP_plus}
+ if (Op1Raw == dwarf::DW_OP_plus_uconst && Op2Raw == dwarf::DW_OP_LLVM_arg &&
+ Op3Raw == Op5Raw && Op3Raw == dwarf::DW_OP_plus &&
+ isConstOperation(Op4Raw)) {
+ auto Result = Op1Arg + Op4Arg;
+ WorkingOps.erase(WorkingOps.begin() + Loc + 5,
+ WorkingOps.begin() + Loc + 8);
+ WorkingOps[Loc + 1] = Result;
+ Cursor.assignNewExpr(WorkingOps);
+ Loc = 0;
+ continue;
+ }
+
+ auto Op6 = Cursor.peekNextN(5);
+ if (!Op6) {
+ moveCursorAndLocPos(Cursor, Loc, *Op1);
+ continue;
+ }
+ auto Op6Raw = Op6->getOp();
+ // {DW_OP_const[u, s], Const1, DW_OP_[plus, mul], DW_OP_LLVM_arg, Arg1,
+ // DW_OP_[plus, mul], DW_OP_const[u, s], Const2, DW_OP_[plus, mul]} ->
+ // {DW_OP_constu, Const1 [+, *] Const2, DW_OP_[plus, mul], DW_OP_LLVM_arg,
+ // Arg1, DW_OP_[plus, mul]}
+ if (isConstOperation(Op1Raw) && Op3Raw == dwarf::DW_OP_LLVM_arg &&
+ isConstOperation(Op5Raw) &&
+ operationsAreFoldableAndCommutative(Op2Raw, Op4Raw) &&
+ operationsAreFoldableAndCommutative(Op4Raw, Op6Raw)) {
+ auto Result = foldOperationIfPossible(Op2Raw, Op1Arg, Op5Arg);
+ if (!Result)
+ llvm_unreachable(
+ "Something went very wrong here! This should always work");
+ WorkingOps.erase(WorkingOps.begin() + Loc + 6,
+ WorkingOps.begin() + Loc + 9);
+ WorkingOps[Loc] = dwarf::DW_OP_constu;
+ WorkingOps[Loc + 1] = *Result;
+ Cursor.assignNewExpr(WorkingOps);
+ Loc = 0;
+ continue;
+ }
+
+ moveCursorAndLocPos(Cursor, Loc, *Op1);
+ }
+ auto *Result = DIExpression::get(getContext(), WorkingOps);
+ assert(Result->isValid() && "concatenated expression is not valid");
+ return Result;
+}
+
uint64_t DIExpression::getNumLocationOperands() const {
uint64_t Result = 0;
for (auto ExprOp : expr_ops())
diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index 1570631287b2a78..2326c5c2c78c630 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -3120,6 +3120,283 @@ TEST_F(DIExpressionTest, get) {
EXPECT_EQ(N0WithPrependedOps, N2);
}
+TEST_F(DIExpressionTest, Fold) {
+
+ // Remove a No-op DW_OP_plus_uconst from an expression.
+ SmallVector<uint64_t, 8> Ops = {dwarf::DW_OP_plus_uconst, 0};
+ auto *Expr = DIExpression::get(Context, Ops);
+ auto *E = Expr->foldConstantMath();
+ SmallVector<uint64_t, 8> ResOps;
+ auto *ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Remove a No-op add from an expression.
+ Ops[0] = dwarf::DW_OP_constu;
+ Ops[1] = 0;
+ Ops.push_back(dwarf::DW_OP_plus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Remove a No-op subtract from an expression.
+ Ops[2] = dwarf::DW_OP_minus;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Remove a No-op shift left from an expression.
+ Ops[2] = dwarf::DW_OP_shl;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Remove a No-op shift right from an expression.
+ Ops[2] = dwarf::DW_OP_shr;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Remove a No-op multiply from an expression.
+ Ops[2] = dwarf::DW_OP_mul;
+ Ops[1] = 1;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Remove a No-op divide from an expression.
+ Ops[2] = dwarf::DW_OP_div;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test fold {DW_OP_plus_uconst, Const1, DW_OP_plus_uconst, Const2} ->
+ // {DW_OP_plus_uconst, Const1 + Const2}
+ Ops[0] = dwarf::DW_OP_plus_uconst;
+ Ops[1] = 2;
+ Ops[2] = dwarf::DW_OP_plus_uconst;
+ Ops.push_back(3);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.push_back(dwarf::DW_OP_plus_uconst);
+ ResOps.push_back(5);
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_plus_uconst, Const2} -> {DW_OP_constu,
+ // Const1 + Const2}
+ Ops[0] = dwarf::DW_OP_constu;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[0] = dwarf::DW_OP_constu;
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_plus} ->
+ // {DW_OP_constu, Const1 + Const2}
+ Ops[1] = 8;
+ Ops[2] = dwarf::DW_OP_constu;
+ Ops[3] = 2;
+ Ops.push_back(dwarf::DW_OP_plus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[0] = dwarf::DW_OP_constu;
+ ResOps[1] = 10;
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_minus} ->
+ // {DW_OP_constu, Const1 - Const2}
+ Ops[4] = dwarf::DW_OP_minus;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[0] = dwarf::DW_OP_constu;
+ ResOps[1] = 6;
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_mul} ->
+ // {DW_OP_constu, Const1 * Const2}
+ Ops[4] = dwarf::DW_OP_mul;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[0] = dwarf::DW_OP_constu;
+ ResOps[1] = 16;
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_div} ->
+ // {DW_OP_constu, Const1 / Const2}
+ Ops[4] = dwarf::DW_OP_div;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[0] = dwarf::DW_OP_constu;
+ ResOps[1] = 4;
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_shl} ->
+ // {DW_OP_constu, Const1 << Const2}
+ Ops[4] = dwarf::DW_OP_shl;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[0] = dwarf::DW_OP_constu;
+ ResOps[1] = 32;
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_shr} ->
+ // {DW_OP_constu, Const1 >> Const2}
+ Ops[4] = dwarf::DW_OP_shr;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[0] = dwarf::DW_OP_constu;
+ ResOps[1] = 2;
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_plus_uconst, Const1, DW_OP_constu, Const2, DW_OP_plus} ->
+ // {DW_OP_plus_uconst, Const1 + Const2}
+ Ops[0] = dwarf::DW_OP_plus_uconst;
+ Ops[1] = 8;
+ Ops[2] = dwarf::DW_OP_constu;
+ Ops[3] = 2;
+ Ops[4] = dwarf::DW_OP_plus;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[0] = dwarf::DW_OP_plus_uconst;
+ ResOps[1] = 10;
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_plus, DW_OP_plus_uconst, Const2} ->
+ // {DW_OP_plus_uconst, Const1 + Const2}
+ Ops[0] = dwarf::DW_OP_constu;
+ Ops[1] = 8;
+ Ops[2] = dwarf::DW_OP_plus;
+ Ops[3] = dwarf::DW_OP_plus_uconst;
+ Ops[4] = 2;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_plus, DW_OP_constu, Const2, DW_OP_plus}
+ // -> {DW_OP_constu, Const1 + Const2, DW_OP_plus}
+ Ops[0] = dwarf::DW_OP_constu;
+ Ops[1] = 8;
+ Ops[2] = dwarf::DW_OP_plus;
+ Ops[3] = dwarf::DW_OP_constu;
+ Ops[4] = 2;
+ Ops.push_back(dwarf::DW_OP_plus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[0] = dwarf::DW_OP_constu;
+ ResOps.push_back(dwarf::DW_OP_plus);
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_mul, DW_OP_constu, Const2, DW_OP_mul} ->
+ // {DW_OP_constu, Const1 + Const2, DW_OP_mul}
+ Ops[0] = dwarf::DW_OP_constu;
+ Ops[1] = 8;
+ Ops[2] = dwarf::DW_OP_mul;
+ Ops[3] = dwarf::DW_OP_constu;
+ Ops[4] = 2;
+ Ops[5] = dwarf::DW_OP_mul;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[1] = 16;
+ ResOps[2] = dwarf::DW_OP_mul;
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_plus_uconst, Const1, DW_OP_plus, DW_OP_LLVM_arg, Arg,
+ // DW_OP_plus, DW_OP_constu, Const2, DW_OP_plus} -> {DW_OP_plus_uconst, Const1
+ // + Const2, DW_OP_LLVM_arg, Arg, DW_OP_plus}
+ Ops[0] = dwarf::DW_OP_plus_uconst;
+ Ops[1] = 8;
+ Ops[2] = dwarf::DW_OP_LLVM_arg;
+ Ops[3] = 0;
+ Ops[4] = dwarf::DW_OP_plus;
+ Ops[5] = dwarf::DW_OP_constu;
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[0] = dwarf::DW_OP_plus_uconst;
+ ResOps[1] = 10;
+ ResOps[2] = dwarf::DW_OP_LLVM_arg;
+ ResOps.push_back(0);
+ ResOps.push_back(dwarf::DW_OP_plus);
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_plus, DW_OP_LLVM_arg, Arg, DW_OP_plus,
+ // DW_OP_plus_uconst, Const2} -> {DW_OP_constu, Const1 + Const2, DW_OP_plus,
+ // DW_OP_LLVM_arg, Arg, DW_OP_plus}
+ Ops[0] = dwarf::DW_OP_constu;
+ Ops[1] = 8;
+ Ops[2] = dwarf::DW_OP_plus;
+ Ops[3] = dwarf::DW_OP_LLVM_arg;
+ Ops[4] = 0;
+ Ops[5] = dwarf::DW_OP_plus;
+ Ops[6] = dwarf::DW_OP_plus_uconst;
+ Ops[7] = 2;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[0] = dwarf::DW_OP_constu;
+ ResOps[1] = 10;
+ ResOps[2] = dwarf::DW_OP_plus;
+ ResOps[3] = dwarf::DW_OP_LLVM_arg;
+ ResOps[4] = 0;
+ ResOps.push_back(dwarf::DW_OP_plus);
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_plus, DW_OP_LLVM_arg, Arg, DW_OP_plus,
+ // DW_OP_constu, Const2, DW_OP_plus} -> {DW_OP_constu, Const1 + Const2,
+ // DW_OP_plus, DW_OP_LLVM_arg, Arg, DW_OP_plus}
+ Ops[0] = dwarf::DW_OP_constu;
+ Ops[1] = 8;
+ Ops[2] = dwarf::DW_OP_plus;
+ Ops[3] = dwarf::DW_OP_LLVM_arg;
+ Ops[4] = 0;
+ Ops[5] = dwarf::DW_OP_plus;
+ Ops[6] = dwarf::DW_OP_constu;
+ Ops[7] = 2;
+ Ops.push_back(dwarf::DW_OP_plus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test {DW_OP_constu, Const1, DW_OP_mul, DW_OP_LLVM_arg, Arg, DW_OP_mul,
+ // DW_OP_constu, Const2, DW_OP_mul} -> {DW_OP_constu, Const1 * Const2,
+ // DW_OP_mul, DW_OP_LLVM_arg, Arg, DW_OP_mul}
+ Ops[0] = dwarf::DW_OP_constu;
+ Ops[1] = 8;
+ Ops[2] = dwarf::DW_OP_mul;
+ Ops[3] = dwarf::DW_OP_LLVM_arg;
+ Ops[4] = 0;
+ Ops[5] = dwarf::DW_OP_mul;
+ Ops[6] = dwarf::DW_OP_constu;
+ Ops[7] = 2;
+ Ops[8] = dwarf::DW_OP_mul;
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps[1] = 16;
+ ResOps[2] = dwarf::DW_OP_mul;
+ ResOps[5] = dwarf::DW_OP_mul;
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+}
+
TEST_F(DIExpressionTest, isValid) {
#define EXPECT_VALID(...) \
do { \
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