C++: restrict dump str generation in aliased_ssa

Author: Robert Marsh

cpp/ql/src/semmle/code/cpp/ir/implementation/IRConfiguration.qll

@@ -16,6 +16,8 @@ class IRConfiguration extends TIRConfiguration {
    * Holds if IR should be created for function `func`. By default, holds for all functions.
    */
   predicate shouldCreateIRForFunction(Language::Function func) { any() }
+
+  predicate shouldEvaluateDebugStringsForFunction(Language::Function func) { any() }
 }
 
 private newtype TIREscapeAnalysisConfiguration = MkIREscapeAnalysisConfiguration()

cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/IRBlock.qll

@@ -27,6 +27,9 @@ class IRBlockBase extends TIRBlock {
    * by debugging and printing code only.
    */
   int getDisplayIndex() {
+    exists(IRConfiguration::IRConfiguration config |
+      config.shouldEvaluateDebugStringsForFunction(this.getEnclosingFunction())
+    ) and
     this =
       rank[result + 1](IRBlock funcBlock |
         funcBlock.getEnclosingFunction() = getEnclosingFunction()

cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/Instruction.qll

@@ -283,6 +283,9 @@ module InstructionSanity {
  * `File` and line number. Used for assigning register names when printing IR.
  */
 private Instruction getAnInstructionAtLine(IRFunction irFunc, Language::File file, int line) {
+  exists(IRConfiguration::IRConfiguration config |
+    config.shouldEvaluateDebugStringsForFunction(irFunc.getFunction())
+  ) and
   exists(Language::Location location |
     irFunc = result.getEnclosingIRFunction() and
     location = result.getLocation() and
@@ -307,13 +310,19 @@ class Instruction extends Construction::TInstruction {
     result = getResultString() + " = " + getOperationString() + " " + getOperandsString()
   }
 
+  predicate shouldGenerateDumpStrings() {
+    exists(IRConfiguration::IRConfiguration config |
+      config.shouldEvaluateDebugStringsForFunction(this.getEnclosingFunction())
+    )
+  }
   /**
    * Gets a string describing the operation of this instruction. This includes
    * the opcode and the immediate value, if any. For example:
    *
    * VariableAddress[x]
    */
   final string getOperationString() {
+    shouldGenerateDumpStrings() and
     if exists(getImmediateString())
     then result = getOperationPrefix() + getOpcode().toString() + "[" + getImmediateString() + "]"
     else result = getOperationPrefix() + getOpcode().toString()
@@ -325,10 +334,12 @@ class Instruction extends Construction::TInstruction {
   string getImmediateString() { none() }
 
   private string getOperationPrefix() {
+    shouldGenerateDumpStrings() and
     if this instanceof SideEffectInstruction then result = "^" else result = ""
   }
 
   private string getResultPrefix() {
+    shouldGenerateDumpStrings() and
     if getResultIRType() instanceof IRVoidType
     then result = "v"
     else
@@ -342,6 +353,7 @@ class Instruction extends Construction::TInstruction {
    * used by debugging and printing code only.
    */
   int getDisplayIndexInBlock() {
+    shouldGenerateDumpStrings() and
     exists(IRBlock block |
       this = block.getInstruction(result)
       or
@@ -355,6 +367,7 @@ class Instruction extends Construction::TInstruction {
   }
 
   private int getLineRank() {
+    shouldGenerateDumpStrings() and
     this =
       rank[result](Instruction instr |
         instr =
@@ -373,6 +386,7 @@ class Instruction extends Construction::TInstruction {
    * Example: `r1_1`
    */
   string getResultId() {
+    shouldGenerateDumpStrings() and
     result = getResultPrefix() + getAST().getLocation().getStartLine() + "_" + getLineRank()
   }
 
@@ -384,6 +398,7 @@ class Instruction extends Construction::TInstruction {
    * Example: `r1_1(int*)`
    */
   final string getResultString() {
+    shouldGenerateDumpStrings() and
     result = getResultId() + "(" + getResultLanguageType().getDumpString() + ")"
   }
 
@@ -394,6 +409,7 @@ class Instruction extends Construction::TInstruction {
    * Example: `func:r3_4, this:r3_5`
    */
   string getOperandsString() {
+    shouldGenerateDumpStrings() and
     result =
       concat(Operand operand |
         operand = getAnOperand()

cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/PrintIR.qll

@@ -18,6 +18,15 @@ class PrintIRConfiguration extends TPrintIRConfiguration {
   predicate shouldPrintFunction(Language::Function func) { any() }
 }
 
+/**
+ * Override of `IRConfiguration` to only evaluate debug strings for the functions that are to be dumped.
+ */
+private class FilteredIRConfiguration extends IRConfiguration {
+  override predicate shouldEvaluateDebugStringsForFunction(Language::Function func) {
+    shouldPrintFunction(func)
+  }
+}
+
 private predicate shouldPrintFunction(Language::Function func) {
   exists(PrintIRConfiguration config | config.shouldPrintFunction(func))
 }

cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/internal/IRInternal.qll

@@ -1,2 +1,3 @@
 import semmle.code.cpp.ir.internal.IRCppLanguage as Language
 import SSAConstruction as Construction
+import semmle.code.cpp.ir.implementation.IRConfiguration as IRConfiguration