C++: Fix performance of IR AliasAnalysis

cpp/ql/src/semmle/code/cpp/ir/internal/Instruction.qll

@@ -66,6 +66,13 @@ module InstructionSanity {
     count(instr.getOperand(tag)) > 1 and
     not tag instanceof UnmodeledUseOperand
   }
+
+  query predicate operandAcrossFunctions(
+    Instruction op, Instruction operand, OperandTag tag
+  ) {
+    operand = op.getOperand(tag) and
+    operand.getFunctionIR() != op.getFunctionIR()
+  }
 }
 
 /**
@@ -262,8 +269,8 @@ class Instruction extends Construction::TInstruction {
     // Register results are always in SSA form.
     not hasMemoryResult() or
     // An unmodeled result will have a use on the `UnmodeledUse` instruction.
-    not exists(UnmodeledUseOperand useTag |
-      hasUse(_, useTag)
+    not exists(Instruction useInstr, UnmodeledUseOperand useTag |
+      this = useInstr.getOperand(useTag)
     )
   }
 
@@ -296,15 +303,6 @@ class Instruction extends Construction::TInstruction {
   final Instruction getAPredecessor() {
     result = getPredecessor(_)
   }
-
-  /**
-   * Holds if the result of this instruction is consumed by `useInstruction` as
-   * an operand with tag `useTag`.
-   */
-  final predicate hasUse(Instruction useInstruction, OperandTag useTag) {
-    useInstruction.getFunctionIR() = funcIR and
-    this = useInstruction.getOperand(useTag)
-  }
 }
 
 class VariableInstruction extends Instruction {

cpp/ql/src/semmle/code/cpp/ssa/internal/aliased_ssa/AliasAnalysis.qll

@@ -160,7 +160,7 @@ predicate operandEscapes(Instruction instr, OperandTag tag) {
 predicate resultEscapes(Instruction instr) {
   // The result escapes if it has at least one use that escapes.
   exists(Instruction useInstr, OperandTag useOperandTag |
-    instr.hasUse(useInstr, useOperandTag) and
+    useInstr.getOperand(useOperandTag) = instr and
     operandEscapes(useInstr, useOperandTag)
   )
 }

cpp/ql/src/semmle/code/cpp/ssa/internal/aliased_ssa/Instruction.qll

@@ -66,6 +66,13 @@ module InstructionSanity {
     count(instr.getOperand(tag)) > 1 and
     not tag instanceof UnmodeledUseOperand
   }
+
+  query predicate operandAcrossFunctions(
+    Instruction op, Instruction operand, OperandTag tag
+  ) {
+    operand = op.getOperand(tag) and
+    operand.getFunctionIR() != op.getFunctionIR()
+  }
 }
 
 /**
@@ -262,8 +269,8 @@ class Instruction extends Construction::TInstruction {
     // Register results are always in SSA form.
     not hasMemoryResult() or
     // An unmodeled result will have a use on the `UnmodeledUse` instruction.
-    not exists(UnmodeledUseOperand useTag |
-      hasUse(_, useTag)
+    not exists(Instruction useInstr, UnmodeledUseOperand useTag |
+      this = useInstr.getOperand(useTag)
     )
   }
 
@@ -296,15 +303,6 @@ class Instruction extends Construction::TInstruction {
   final Instruction getAPredecessor() {
     result = getPredecessor(_)
   }
-
-  /**
-   * Holds if the result of this instruction is consumed by `useInstruction` as
-   * an operand with tag `useTag`.
-   */
-  final predicate hasUse(Instruction useInstruction, OperandTag useTag) {
-    useInstruction.getFunctionIR() = funcIR and
-    this = useInstruction.getOperand(useTag)
-  }
 }
 
 class VariableInstruction extends Instruction {

cpp/ql/src/semmle/code/cpp/ssa/internal/ssa/AliasAnalysis.qll

@@ -160,7 +160,7 @@ predicate operandEscapes(Instruction instr, OperandTag tag) {
 predicate resultEscapes(Instruction instr) {
   // The result escapes if it has at least one use that escapes.
   exists(Instruction useInstr, OperandTag useOperandTag |
-    instr.hasUse(useInstr, useOperandTag) and
+    useInstr.getOperand(useOperandTag) = instr and
     operandEscapes(useInstr, useOperandTag)
   )
 }

cpp/ql/src/semmle/code/cpp/ssa/internal/ssa/Instruction.qll

@@ -66,6 +66,13 @@ module InstructionSanity {
     count(instr.getOperand(tag)) > 1 and
     not tag instanceof UnmodeledUseOperand
   }
+
+  query predicate operandAcrossFunctions(
+    Instruction op, Instruction operand, OperandTag tag
+  ) {
+    operand = op.getOperand(tag) and
+    operand.getFunctionIR() != op.getFunctionIR()
+  }
 }
 
 /**
@@ -262,8 +269,8 @@ class Instruction extends Construction::TInstruction {
     // Register results are always in SSA form.
     not hasMemoryResult() or
     // An unmodeled result will have a use on the `UnmodeledUse` instruction.
-    not exists(UnmodeledUseOperand useTag |
-      hasUse(_, useTag)
+    not exists(Instruction useInstr, UnmodeledUseOperand useTag |
+      this = useInstr.getOperand(useTag)
     )
   }
 
@@ -296,15 +303,6 @@ class Instruction extends Construction::TInstruction {
   final Instruction getAPredecessor() {
     result = getPredecessor(_)
   }
-
-  /**
-   * Holds if the result of this instruction is consumed by `useInstruction` as
-   * an operand with tag `useTag`.
-   */
-  final predicate hasUse(Instruction useInstruction, OperandTag useTag) {
-    useInstruction.getFunctionIR() = funcIR and
-    this = useInstruction.getOperand(useTag)
-  }
 }
 
 class VariableInstruction extends Instruction {

cpp/ql/test/library-tests/ir/ir/AliasedSSAIRSanity.expected

@@ -1,3 +1,4 @@
 missingOperand
 unexpectedOperand
 duplicateOperand
+operandAcrossFunctions

cpp/ql/test/library-tests/ir/ir/IRSanity.expected

@@ -1,3 +1,4 @@
 missingOperand
 unexpectedOperand
 duplicateOperand
+operandAcrossFunctions

cpp/ql/test/library-tests/ir/ir/SSAIRSanity.expected

@@ -1,3 +1,4 @@
 missingOperand
 unexpectedOperand
 duplicateOperand
+operandAcrossFunctions