[clang] Fix analyzer crash on 'StructuralValue' (PR #79764)

[Andrey Ali Khan Bolshakov via cfe-commits]

https://github.com/bolshakov-a updated https://github.com/llvm/llvm-project/pull/79764

>From 474f86604c35bea7041bcf3e6f8e2103d180902f Mon Sep 17 00:00:00 2001
From: Bolshakov <bolsh.andrey at yandex.ru>
Date: Sun, 28 Jan 2024 21:12:10 +0300
Subject: [PATCH] Fix crashes on 'StructuralValue'

`OpaqueValueExpr` doesn't necessarily contain a source expression.
Particularly, after #78041, it is used to carry the type and the value
kind of a non-type template argument of floating-point type or referring
to a subobject (those are so called `StructuralValue` arguments).

This fixes #79575.
---
 clang/lib/Sema/SemaDecl.cpp                   |  3 ++-
 clang/lib/StaticAnalyzer/Core/Environment.cpp |  8 +++++---
 clang/test/Analysis/templates.cpp             | 13 +++++++++++++
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index e725e187fc9ea08..9bf1e9dd084331f 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -12753,7 +12753,8 @@ namespace {
       }
 
       if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) {
-        HandleValue(OVE->getSourceExpr());
+        if (Expr *SE = OVE->getSourceExpr())
+          HandleValue(SE);
         return;
       }
 
diff --git a/clang/lib/StaticAnalyzer/Core/Environment.cpp b/clang/lib/StaticAnalyzer/Core/Environment.cpp
index 4f989ed59bee38c..427f51109853bda 100644
--- a/clang/lib/StaticAnalyzer/Core/Environment.cpp
+++ b/clang/lib/StaticAnalyzer/Core/Environment.cpp
@@ -40,8 +40,11 @@ static const Expr *ignoreTransparentExprs(const Expr *E) {
 
   switch (E->getStmtClass()) {
   case Stmt::OpaqueValueExprClass:
-    E = cast<OpaqueValueExpr>(E)->getSourceExpr();
-    break;
+    if (const Expr *SE = cast<OpaqueValueExpr>(E)->getSourceExpr()) {
+      E = SE;
+      break;
+    }
+    return E;
   case Stmt::ExprWithCleanupsClass:
     E = cast<ExprWithCleanups>(E)->getSubExpr();
     break;
@@ -98,7 +101,6 @@ SVal Environment::getSVal(const EnvironmentEntry &Entry,
   case Stmt::CXXBindTemporaryExprClass:
   case Stmt::ExprWithCleanupsClass:
   case Stmt::GenericSelectionExprClass:
-  case Stmt::OpaqueValueExprClass:
   case Stmt::ConstantExprClass:
   case Stmt::ParenExprClass:
   case Stmt::SubstNonTypeTemplateParmExprClass:
diff --git a/clang/test/Analysis/templates.cpp b/clang/test/Analysis/templates.cpp
index 061c19fe7e04451..6da1821b70f26fa 100644
--- a/clang/test/Analysis/templates.cpp
+++ b/clang/test/Analysis/templates.cpp
@@ -68,3 +68,16 @@ namespace rdar13954714 {
   // force instantiation
   template void blockWithStatic<true>();
 }
+
+namespace structural_value_crash {
+  constexpr char abc[] = "abc";
+
+  template <const char* in>
+  void use_template_param() {
+    const char *p = in;
+  }
+
+  void force_instantiate() {
+    use_template_param<abc>();
+  }
+}