From 44b6af652ecf1e0ac14fe5dc2de12d0db8faff2d Mon Sep 17 00:00:00 2001
From: Robert Marsh <rdmarsh@semmle.com>
Date: Mon, 5 Dec 2022 12:37:16 -0500
Subject: [PATCH] C++: use Options::exits() for noreturn functions

---
 .../aliased_ssa/internal/SSAConstruction.qll  | 20 +++++++++++--------
 .../raw/internal/IRConstruction.qll           |  5 +----
 .../raw/internal/TranslatedCall.qll           |  7 ++++++-
 3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/internal/SSAConstruction.qll b/cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/internal/SSAConstruction.qll
index 233db262118..2269765f99f 100644
--- a/cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/internal/SSAConstruction.qll
+++ b/cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/internal/SSAConstruction.qll
@@ -34,9 +34,13 @@ private module Cached {
 
   cached
   predicate hasUnreachedInstructionCached(IRFunction irFunc) {
-    exists(OldInstruction oldInstruction |
+    exists(OldIR::Instruction oldInstruction |
       irFunc = oldInstruction.getEnclosingIRFunction() and
-      Reachability::isInfeasibleInstructionSuccessor(oldInstruction, _)
+      (
+        Reachability::isInfeasibleInstructionSuccessor(oldInstruction, _)
+        or
+        oldInstruction.getOpcode() instanceof Opcode::Unreached
+      )
     )
   }
 
@@ -368,18 +372,18 @@ private module Cached {
       kind instanceof GotoEdge
     else (
       exists(OldInstruction oldInstruction |
-        oldInstruction = getOldInstruction(instruction) and
+        (
+          oldInstruction = getOldInstruction(instruction) 
+          or
+          instruction = getChi(oldInstruction)
+        )
+        and
         (
           if Reachability::isInfeasibleInstructionSuccessor(oldInstruction, kind)
           then result = unreachedInstruction(instruction.getEnclosingIRFunction())
           else result = getNewInstruction(oldInstruction.getSuccessor(kind))
         )
       )
-      or
-      exists(OldInstruction oldInstruction |
-        instruction = getChi(oldInstruction) and
-        result = getNewInstruction(oldInstruction.getSuccessor(kind))
-      )
     )
   }
 
diff --git a/cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/IRConstruction.qll b/cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/IRConstruction.qll
index c08fc2a2a8d..be8f2fbab39 100644
--- a/cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/IRConstruction.qll
+++ b/cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/IRConstruction.qll
@@ -396,10 +396,7 @@ Instruction getPrimaryInstructionForSideEffect(SideEffectInstruction instruction
 predicate hasUnreachedInstruction(IRFunction func) {
   exists(Call c | 
     c.getEnclosingFunction() = func.getFunction() and
-    (
-      c.getTarget().hasSpecifier("_Noreturn") or
-      c.getTarget().getAnAttribute().hasName("noreturn")
-    )
+    any(Options opt).exits(c.getTarget())
   )
 }
 
diff --git a/cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/TranslatedCall.qll b/cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/TranslatedCall.qll
index 6619a227e3f..e7226eb505a 100644
--- a/cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/TranslatedCall.qll
+++ b/cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/TranslatedCall.qll
@@ -8,6 +8,7 @@ private import SideEffects
 private import TranslatedElement
 private import TranslatedExpr
 private import TranslatedFunction
+private import DefaultOptions as DefaultOptions
 
 /**
  * Gets the `CallInstruction` from the `TranslatedCallExpr` for the specified expression.
@@ -68,7 +69,7 @@ abstract class TranslatedCall extends TranslatedExpr {
     child = getSideEffects() and
     if this.isNoReturn()
     then result = any(UnreachedInstruction instr | this.getEnclosingFunction().getFunction() = instr.getEnclosingFunction())
-    else result = getParent().getChildSuccessor(this)
+    else result = this.getParent().getChildSuccessor(this)
   }
 
   override Instruction getInstructionSuccessor(InstructionTag tag, EdgeKind kind) {
@@ -272,6 +273,10 @@ abstract class TranslatedCallExpr extends TranslatedNonConstantExpr, TranslatedC
   }
 
   final override int getNumberOfArguments() { result = expr.getNumberOfArguments() }
+
+  final override predicate isNoReturn() {
+    any(Options opt).exits(expr.getTarget())
+  }
 }
 
 /**