[llvm] Introduce DIExpression::foldConstantMath() (PR #71718)
Shubham Sandeep Rastogi via llvm-commits
llvm-commits at lists.llvm.org
Wed May 29 15:48:27 PDT 2024
https://github.com/rastogishubham updated https://github.com/llvm/llvm-project/pull/71718
>From f2afb3462b9e7c7294b853369073bf2a87017fef 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] 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/CMakeLists.txt | 1 +
llvm/lib/IR/DIExpressionOptimizer.cpp | 378 +++++++++++++++++++
llvm/lib/IR/DebugInfoMetadata.cpp | 1 -
llvm/unittests/IR/MetadataTest.cpp | 457 +++++++++++++++++++++++
5 files changed, 841 insertions(+), 1 deletion(-)
create mode 100644 llvm/lib/IR/DIExpressionOptimizer.cpp
diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
index 555bd623ad9ef..18873a551595a 100644
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -3121,6 +3121,11 @@ class DIExpression : public MDNode {
/// expression and constant on failure.
std::pair<DIExpression *, const ConstantInt *>
constantFold(const ConstantInt *CI);
+
+ /// Try to shorten an expression with constant math operations that can be
+ /// evaluated 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/CMakeLists.txt b/llvm/lib/IR/CMakeLists.txt
index b5fb7409d8e88..20f169913087a 100644
--- a/llvm/lib/IR/CMakeLists.txt
+++ b/llvm/lib/IR/CMakeLists.txt
@@ -17,6 +17,7 @@ add_llvm_component_library(LLVMCore
DataLayout.cpp
DebugInfo.cpp
DebugInfoMetadata.cpp
+ DIExpressionOptimizer.cpp
DebugProgramInstruction.cpp
DebugLoc.cpp
DiagnosticHandler.cpp
diff --git a/llvm/lib/IR/DIExpressionOptimizer.cpp b/llvm/lib/IR/DIExpressionOptimizer.cpp
new file mode 100644
index 0000000000000..2bb8eac348c8e
--- /dev/null
+++ b/llvm/lib/IR/DIExpressionOptimizer.cpp
@@ -0,0 +1,378 @@
+//===- DIExpressionOptimizer.cpp - Constant folding of DIExpressions ------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements functions to constant fold DIExpressions. Which were
+// declared in DIExpressionOptimizer.h
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/IR/DebugInfoMetadata.h"
+
+using namespace llvm;
+
+/// Returns true if the Op is a DW_OP_constu.
+static std::optional<uint64_t> isConstantVal(DIExpression::ExprOperand Op) {
+ if (Op.getOp() == dwarf::DW_OP_constu)
+ return Op.getArg(0);
+ return std::nullopt;
+}
+
+/// Returns true if an operation and operand result in a No Op.
+static bool isNeutralElement(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;
+ }
+}
+
+/// Try to fold \p Const1 and \p Const2 by applying \p Operator and returning
+/// the result, if there is an overflow, return a std::nullopt.
+static std::optional<uint64_t>
+foldOperationIfPossible(uint64_t Const1, uint64_t Const2,
+ dwarf::LocationAtom Operator) {
+
+ bool ResultOverflowed;
+ switch (Operator) {
+ case dwarf::DW_OP_plus: {
+ auto Result = SaturatingAdd(Const1, Const2, &ResultOverflowed);
+ if (ResultOverflowed)
+ return std::nullopt;
+ return Result;
+ }
+ case dwarf::DW_OP_minus: {
+ if (Const1 < Const2)
+ return std::nullopt;
+ return Const1 - Const2;
+ }
+ case dwarf::DW_OP_shl: {
+ if ((uint64_t)countl_zero(Const1) < Const2)
+ return std::nullopt;
+ return Const1 << Const2;
+ }
+ case dwarf::DW_OP_shr: {
+ if ((uint64_t)countr_zero(Const1) < Const2)
+ return std::nullopt;
+ return Const1 >> Const2;
+ }
+ case dwarf::DW_OP_mul: {
+ auto Result = SaturatingMultiply(Const1, Const2, &ResultOverflowed);
+ if (ResultOverflowed)
+ return std::nullopt;
+ return Result;
+ }
+ case dwarf::DW_OP_div: {
+ if (Const2)
+ return Const1 / Const2;
+ return std::nullopt;
+ }
+ default:
+ return std::nullopt;
+ }
+}
+
+/// Returns true if the two operations \p Operator1 and \p Operator2 are
+/// commutative and can be folded.
+static bool operationsAreFoldableAndCommutative(dwarf::LocationAtom Operator1,
+ dwarf::LocationAtom Operator2) {
+ return Operator1 == Operator2 &&
+ (Operator1 == dwarf::DW_OP_plus || Operator1 == dwarf::DW_OP_mul);
+}
+
+/// Consume one operator and its operand(s).
+static void consumeOneOperator(DIExpressionCursor &Cursor, uint64_t &Loc,
+ const DIExpression::ExprOperand &Op) {
+ Cursor.consume(1);
+ Loc = Loc + Op.getSize();
+}
+
+/// Reset the Cursor to the beginning of the WorkingOps.
+void startFromBeginning(uint64_t &Loc, DIExpressionCursor &Cursor,
+ ArrayRef<uint64_t> WorkingOps) {
+ Cursor.assignNewExpr(WorkingOps);
+ Loc = 0;
+}
+
+/// This function will canonicalize:
+/// 1. DW_OP_plus_uconst to DW_OP_constu <const-val> DW_OP_plus
+/// 2. DW_OP_lit<n> to DW_OP_constu <n>
+static SmallVector<uint64_t>
+canonicalizeDwarfOperations(ArrayRef<uint64_t> WorkingOps) {
+ DIExpressionCursor Cursor(WorkingOps);
+ uint64_t Loc = 0;
+ SmallVector<uint64_t> ResultOps;
+ while (Loc < WorkingOps.size()) {
+ auto Op = Cursor.peek();
+ /// Expression has no operations, break.
+ if (!Op)
+ break;
+ auto OpRaw = Op->getOp();
+
+ if (OpRaw >= dwarf::DW_OP_lit0 && OpRaw <= dwarf::DW_OP_lit31) {
+ ResultOps.push_back(dwarf::DW_OP_constu);
+ ResultOps.push_back(OpRaw - dwarf::DW_OP_lit0);
+ consumeOneOperator(Cursor, Loc, *Cursor.peek());
+ continue;
+ }
+ if (OpRaw == dwarf::DW_OP_plus_uconst) {
+ ResultOps.push_back(dwarf::DW_OP_constu);
+ ResultOps.push_back(Op->getArg(0));
+ ResultOps.push_back(dwarf::DW_OP_plus);
+ consumeOneOperator(Cursor, Loc, *Cursor.peek());
+ continue;
+ }
+ uint64_t PrevLoc = Loc;
+ consumeOneOperator(Cursor, Loc, *Cursor.peek());
+ ResultOps.append(WorkingOps.begin() + PrevLoc, WorkingOps.begin() + Loc);
+ }
+ return ResultOps;
+}
+
+/// This function will convert:
+/// 1. DW_OP_constu <const-val> DW_OP_plus to DW_OP_plus_uconst
+/// 2. DW_OP_constu, 0 to DW_OP_lit0
+static SmallVector<uint64_t>
+optimizeDwarfOperations(ArrayRef<uint64_t> WorkingOps) {
+ DIExpressionCursor Cursor(WorkingOps);
+ uint64_t Loc = 0;
+ SmallVector<uint64_t> ResultOps;
+ while (Loc < WorkingOps.size()) {
+ auto Op1 = Cursor.peek();
+ /// Expression has no operations, exit.
+ if (!Op1)
+ break;
+ auto Op1Raw = Op1->getOp();
+
+ if (Op1Raw == dwarf::DW_OP_constu && Op1->getArg(0) == 0) {
+ ResultOps.push_back(dwarf::DW_OP_lit0);
+ consumeOneOperator(Cursor, Loc, *Cursor.peek());
+ continue;
+ }
+
+ auto Op2 = Cursor.peekNext();
+ /// Expression has no more operations, copy into ResultOps and exit.
+ if (!Op2) {
+ uint64_t PrevLoc = Loc;
+ consumeOneOperator(Cursor, Loc, *Cursor.peek());
+ ResultOps.append(WorkingOps.begin() + PrevLoc, WorkingOps.begin() + Loc);
+ break;
+ }
+ auto Op2Raw = Op2->getOp();
+
+ if (Op1Raw == dwarf::DW_OP_constu && Op2Raw == dwarf::DW_OP_plus) {
+ ResultOps.push_back(dwarf::DW_OP_plus_uconst);
+ ResultOps.push_back(Op1->getArg(0));
+ consumeOneOperator(Cursor, Loc, *Cursor.peek());
+ consumeOneOperator(Cursor, Loc, *Cursor.peek());
+ continue;
+ }
+ uint64_t PrevLoc = Loc;
+ consumeOneOperator(Cursor, Loc, *Cursor.peek());
+ ResultOps.append(WorkingOps.begin() + PrevLoc, WorkingOps.begin() + Loc);
+ }
+ return ResultOps;
+}
+
+/// {DW_OP_constu, 0, DW_OP_[plus, minus, shl, shr]} -> {}
+/// {DW_OP_constu, 1, DW_OP_[mul, div]} -> {}
+static bool tryFoldNoOpMath(uint64_t Const1,
+ ArrayRef<DIExpression::ExprOperand> Ops,
+ uint64_t &Loc, DIExpressionCursor &Cursor,
+ SmallVectorImpl<uint64_t> &WorkingOps) {
+
+ if (isNeutralElement(Ops[1].getOp(), Const1)) {
+ WorkingOps.erase(WorkingOps.begin() + Loc, WorkingOps.begin() + Loc + 3);
+ startFromBeginning(Loc, Cursor, WorkingOps);
+ return true;
+ }
+ return false;
+}
+
+/// {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_[plus,
+/// minus, mul, div, shl, shr] -> {DW_OP_constu, Const1 [+, -, *, /, <<, >>]
+/// Const2}
+static bool tryFoldConstants(uint64_t Const1,
+ ArrayRef<DIExpression::ExprOperand> Ops,
+ uint64_t &Loc, DIExpressionCursor &Cursor,
+ SmallVectorImpl<uint64_t> &WorkingOps) {
+
+ auto Const2 = isConstantVal(Ops[1]);
+ if (!Const2)
+ return false;
+
+ auto Result = foldOperationIfPossible(
+ Const1, *Const2, static_cast<dwarf::LocationAtom>(Ops[2].getOp()));
+ if (!Result) {
+ consumeOneOperator(Cursor, Loc, Ops[0]);
+ return true;
+ }
+ WorkingOps.erase(WorkingOps.begin() + Loc + 2, WorkingOps.begin() + Loc + 5);
+ WorkingOps[Loc] = dwarf::DW_OP_constu;
+ WorkingOps[Loc + 1] = *Result;
+ startFromBeginning(Loc, Cursor, WorkingOps);
+ return true;
+}
+
+/// {DW_OP_constu, Const1, DW_OP_[plus, mul], DW_OP_constu, Const2,
+/// DW_OP_[plus, mul]} -> {DW_OP_constu, Const1 [+, *] Const2, DW_OP_[plus,
+/// mul]}
+static bool tryFoldCommutativeMath(uint64_t Const1,
+ ArrayRef<DIExpression::ExprOperand> Ops,
+ uint64_t &Loc, DIExpressionCursor &Cursor,
+ SmallVectorImpl<uint64_t> &WorkingOps) {
+
+ auto Const2 = isConstantVal(Ops[2]);
+ auto Operand1 = static_cast<dwarf::LocationAtom>(Ops[1].getOp());
+ auto Operand2 = static_cast<dwarf::LocationAtom>(Ops[3].getOp());
+
+ if (!Const2 || !operationsAreFoldableAndCommutative(Operand1, Operand2))
+ return false;
+
+ auto Result = foldOperationIfPossible(Const1, *Const2, Operand1);
+ if (!Result) {
+ consumeOneOperator(Cursor, Loc, Ops[0]);
+ return true;
+ }
+ WorkingOps.erase(WorkingOps.begin() + Loc + 3, WorkingOps.begin() + Loc + 6);
+ WorkingOps[Loc] = dwarf::DW_OP_constu;
+ WorkingOps[Loc + 1] = *Result;
+ startFromBeginning(Loc, Cursor, WorkingOps);
+ return true;
+}
+
+/// {DW_OP_constu, Const1, DW_OP_[plus, mul], DW_OP_LLVM_arg, Arg1,
+/// DW_OP_[plus, mul], DW_OP_constu, Const2, DW_OP_[plus, mul]} ->
+/// {DW_OP_constu, Const1 [+, *] Const2, DW_OP_[plus, mul], DW_OP_LLVM_arg,
+/// Arg1, DW_OP_[plus, mul]}
+static bool tryFoldCommutativeMathWithArgInBetween(
+ uint64_t Const1, ArrayRef<DIExpression::ExprOperand> Ops, uint64_t &Loc,
+ DIExpressionCursor &Cursor, SmallVectorImpl<uint64_t> &WorkingOps) {
+
+ auto Const2 = isConstantVal(Ops[4]);
+ auto Operand1 = static_cast<dwarf::LocationAtom>(Ops[1].getOp());
+ auto Operand2 = static_cast<dwarf::LocationAtom>(Ops[3].getOp());
+ auto Operand3 = static_cast<dwarf::LocationAtom>(Ops[5].getOp());
+
+ if (!Const2 || Ops[2].getOp() != dwarf::DW_OP_LLVM_arg ||
+ !operationsAreFoldableAndCommutative(Operand1, Operand2) ||
+ !operationsAreFoldableAndCommutative(Operand2, Operand3))
+ return false;
+
+ auto Result = foldOperationIfPossible(Const1, *Const2, Operand1);
+ if (!Result) {
+ consumeOneOperator(Cursor, Loc, Ops[0]);
+ return true;
+ }
+ WorkingOps.erase(WorkingOps.begin() + Loc + 6, WorkingOps.begin() + Loc + 9);
+ WorkingOps[Loc] = dwarf::DW_OP_constu;
+ WorkingOps[Loc + 1] = *Result;
+ startFromBeginning(Loc, Cursor, WorkingOps);
+ return true;
+}
+
+DIExpression *DIExpression::foldConstantMath() {
+
+ SmallVector<uint64_t, 8> WorkingOps(Elements.begin(), Elements.end());
+ uint64_t Loc = 0;
+ SmallVector<uint64_t> ResultOps = canonicalizeDwarfOperations(WorkingOps);
+ DIExpressionCursor Cursor(ResultOps);
+ SmallVector<DIExpression::ExprOperand, 8> Ops;
+
+ // Iterate over all Operations in a DIExpression to match the smallest pattern
+ // that can be folded.
+ while (Loc < ResultOps.size()) {
+ Ops.clear();
+
+ auto Op = Cursor.peek();
+ // Expression has no operations, exit.
+ if (!Op)
+ break;
+
+ auto Const1 = isConstantVal(*Op);
+
+ if (!Const1) {
+ // Early exit, all of the following patterns start with a constant value.
+ consumeOneOperator(Cursor, Loc, *Op);
+ continue;
+ }
+
+ Ops.push_back(*Op);
+
+ Op = Cursor.peekNext();
+ // All following patterns require at least 2 Operations, exit.
+ if (!Op)
+ break;
+
+ Ops.push_back(*Op);
+
+ // Try to fold a constant no-op, such as {+ 0}
+ if (tryFoldNoOpMath(*Const1, Ops, Loc, Cursor, ResultOps))
+ continue;
+
+ Op = Cursor.peekNextN(2);
+ // Op[1] could still match a pattern, skip iteration.
+ if (!Op) {
+ consumeOneOperator(Cursor, Loc, Ops[0]);
+ continue;
+ }
+
+ Ops.push_back(*Op);
+
+ // Try to fold a pattern of two constants such as {C1 + C2}.
+ if (tryFoldConstants(*Const1, Ops, Loc, Cursor, ResultOps))
+ continue;
+
+ Op = Cursor.peekNextN(3);
+ // Op[1] and Op[2] could still match a pattern, skip iteration.
+ if (!Op) {
+ consumeOneOperator(Cursor, Loc, Ops[0]);
+ continue;
+ }
+
+ Ops.push_back(*Op);
+
+ // Try to fold commutative constant math, such as {C1 + C2 +}.
+ if (tryFoldCommutativeMath(*Const1, Ops, Loc, Cursor, ResultOps))
+ continue;
+
+ Op = Cursor.peekNextN(4);
+ if (!Op) {
+ consumeOneOperator(Cursor, Loc, Ops[0]);
+ continue;
+ }
+
+ Ops.push_back(*Op);
+ Op = Cursor.peekNextN(5);
+ if (!Op) {
+ consumeOneOperator(Cursor, Loc, Ops[0]);
+ continue;
+ }
+
+ Ops.push_back(*Op);
+
+ // Try to fold commutative constant math with an LLVM_Arg in between, such
+ // as {C1 + Arg + C2 +}.
+ if (tryFoldCommutativeMathWithArgInBetween(*Const1, Ops, Loc, Cursor,
+ ResultOps))
+ continue;
+
+ consumeOneOperator(Cursor, Loc, Ops[0]);
+ }
+ ResultOps = optimizeDwarfOperations(ResultOps);
+ auto *Result = DIExpression::get(getContext(), ResultOps);
+ assert(Result->isValid() && "concatenated expression is not valid");
+ return Result;
+}
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 570515505607f..229ee2bd0164c 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -1880,7 +1880,6 @@ 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");
diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index 4c2e5f77a5403..9647ac8c43966 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -3153,6 +3153,463 @@ 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 *EmptyExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, EmptyExpr);
+
+ // Remove a No-op add from an expression.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(0);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ EXPECT_EQ(E, EmptyExpr);
+
+ // Remove a No-op subtract from an expression.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(0);
+ Ops.push_back(dwarf::DW_OP_minus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ EXPECT_EQ(E, EmptyExpr);
+
+ // Remove a No-op shift left from an expression.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(0);
+ Ops.push_back(dwarf::DW_OP_shl);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ EXPECT_EQ(E, EmptyExpr);
+
+ // Remove a No-op shift right from an expression.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(0);
+ Ops.push_back(dwarf::DW_OP_shr);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ EXPECT_EQ(E, EmptyExpr);
+
+ // Remove a No-op multiply from an expression.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(1);
+ Ops.push_back(dwarf::DW_OP_mul);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ EXPECT_EQ(E, EmptyExpr);
+
+ // Remove a No-op divide from an expression.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(1);
+ Ops.push_back(dwarf::DW_OP_div);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ EXPECT_EQ(E, EmptyExpr);
+
+ // Test fold {DW_OP_plus_uconst, Const1, DW_OP_plus_uconst, Const2} ->
+ // {DW_OP_plus_uconst, Const1 + Const2}
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_plus_uconst);
+ Ops.push_back(2);
+ Ops.push_back(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);
+ auto *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.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_plus_uconst);
+ Ops.push_back(3);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(5);
+ 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.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(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.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_minus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(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.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_mul);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(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.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_div);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(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.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_shl);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(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.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_shr);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(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.clear();
+ Ops.push_back(dwarf::DW_OP_plus_uconst);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_plus_uconst);
+ ResOps.push_back(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.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Ops.push_back(dwarf::DW_OP_plus_uconst);
+ Ops.push_back(2);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_plus_uconst);
+ ResOps.push_back(10);
+ 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_plus_uconst, Const1 + Const2}
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_plus_uconst);
+ ResOps.push_back(10);
+ 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.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_mul);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_mul);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(16);
+ ResOps.push_back(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.clear();
+ Ops.push_back(dwarf::DW_OP_plus_uconst);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_LLVM_arg);
+ Ops.push_back(0);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_plus_uconst);
+ ResOps.push_back(10);
+ ResOps.push_back(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.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Ops.push_back(dwarf::DW_OP_LLVM_arg);
+ Ops.push_back(0);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Ops.push_back(dwarf::DW_OP_plus_uconst);
+ Ops.push_back(2);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_plus_uconst);
+ ResOps.push_back(10);
+ ResOps.push_back(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_constu, Const2, DW_OP_plus} -> {DW_OP_constu, Const1 + Const2,
+ // DW_OP_plus, DW_OP_LLVM_arg, Arg, DW_OP_plus}
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Ops.push_back(dwarf::DW_OP_LLVM_arg);
+ Ops.push_back(0);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_plus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_plus_uconst);
+ ResOps.push_back(10);
+ ResOps.push_back(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_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.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(8);
+ Ops.push_back(dwarf::DW_OP_mul);
+ Ops.push_back(dwarf::DW_OP_LLVM_arg);
+ Ops.push_back(0);
+ Ops.push_back(dwarf::DW_OP_mul);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_mul);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(16);
+ ResOps.push_back(dwarf::DW_OP_mul);
+ ResOps.push_back(dwarf::DW_OP_LLVM_arg);
+ ResOps.push_back(0);
+ ResOps.push_back(dwarf::DW_OP_mul);
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test an overflow addition.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_plus_uconst);
+ Ops.push_back(UINT64_MAX);
+ Ops.push_back(dwarf::DW_OP_plus_uconst);
+ Ops.push_back(2);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_plus_uconst);
+ ResOps.push_back(UINT64_MAX);
+ ResOps.push_back(dwarf::DW_OP_plus_uconst);
+ ResOps.push_back(2);
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test an underflow subtraction.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(1);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_minus);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(1);
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(2);
+ ResOps.push_back(dwarf::DW_OP_minus);
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test a left shift greater than 64.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(1);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(65);
+ Ops.push_back(dwarf::DW_OP_shl);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(1);
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(65);
+ ResOps.push_back(dwarf::DW_OP_shl);
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test a right shift greater than 64.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(1);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(65);
+ Ops.push_back(dwarf::DW_OP_shr);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(1);
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(65);
+ ResOps.push_back(dwarf::DW_OP_shr);
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test an overflow multiplication.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(UINT64_MAX);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_mul);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(UINT64_MAX);
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(2);
+ ResOps.push_back(dwarf::DW_OP_mul);
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+
+ // Test a divide by 0.
+ Ops.clear();
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(2);
+ Ops.push_back(dwarf::DW_OP_constu);
+ Ops.push_back(0);
+ Ops.push_back(dwarf::DW_OP_div);
+ Expr = DIExpression::get(Context, Ops);
+ E = Expr->foldConstantMath();
+ ResOps.clear();
+ ResOps.push_back(dwarf::DW_OP_constu);
+ ResOps.push_back(2);
+ ResOps.push_back(dwarf::DW_OP_lit0);
+ ResOps.push_back(dwarf::DW_OP_div);
+ ResExpr = DIExpression::get(Context, ResOps);
+ EXPECT_EQ(E, ResExpr);
+}
+
TEST_F(DIExpressionTest, isValid) {
#define EXPECT_VALID(...) \
do { \
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