[analyzer] Update the undefined assignment checker diagnostics to not use the term 'garbage' (#126596)

A clang user pointed out that messages for the static analyzer undefined
assignment checker use the term ‘garbage’, which might have a negative
connotation to some users. This change updates the messages to use the
term ‘uninitialized’. This is the usual reason why a value is undefined
in the static analyzer and describes the logical error that a programmer
should take action to fix.

Out-of-bounds reads can also produce undefined values in the static
analyzer. The right long-term design is to have to the array bounds
checker cover out-of-bounds reads, so we do not cover that case in the
updated messages. The recent improvements to the array bounds checker
make it a candidate to add to the core set of checkers.

rdar://133418644

Author: dtarditi

clang/lib/StaticAnalyzer/Checkers/UndefinedAssignmentChecker.cpp

@@ -23,7 +23,7 @@ using namespace ento;
 namespace {
 class UndefinedAssignmentChecker
   : public Checker<check::Bind> {
-  const BugType BT{this, "Assigned value is garbage or undefined"};
+  const BugType BT{this, "Assigned value is uninitialized"};
 
 public:
   void checkBind(SVal location, SVal val, const Stmt *S,
@@ -57,8 +57,7 @@ void UndefinedAssignmentChecker::checkBind(SVal location, SVal val,
 
   while (StoreE) {
     if (const UnaryOperator *U = dyn_cast<UnaryOperator>(StoreE)) {
-      OS << "The expression is an uninitialized value. "
-            "The computed value will also be garbage";
+      OS << "The expression uses uninitialized memory";
 
       ex = U->getSubExpr();
       break;
@@ -67,8 +66,8 @@ void UndefinedAssignmentChecker::checkBind(SVal location, SVal val,
     if (const BinaryOperator *B = dyn_cast<BinaryOperator>(StoreE)) {
       if (B->isCompoundAssignmentOp()) {
         if (C.getSVal(B->getLHS()).isUndef()) {
-          OS << "The left expression of the compound assignment is an "
-                "uninitialized value. The computed value will also be garbage";
+          OS << "The left expression of the compound assignment uses "
+             << "uninitialized memory";
           ex = B->getLHS();
           break;
         }
@@ -89,7 +88,7 @@ void UndefinedAssignmentChecker::checkBind(SVal location, SVal val,
         for (auto *I : CD->inits()) {
           if (I->getInit()->IgnoreImpCasts() == StoreE) {
             OS << "Value assigned to field '" << I->getMember()->getName()
-               << "' in implicit constructor is garbage or undefined";
+               << "' in implicit constructor is uninitialized";
             break;
           }
         }

clang/test/Analysis/Inputs/expected-plists/edges-new.mm.plist

@@ -2578,17 +2578,17 @@
      </array>
      <key>depth</key><integer>0</integer>
      <key>extended_message</key>
-     <string>The left expression of the compound assignment is an uninitialized value. The computed value will also be garbage</string>
+     <string>The left expression of the compound assignment uses uninitialized memory</string>
      <key>message</key>
-     <string>The left expression of the compound assignment is an uninitialized value. The computed value will also be garbage</string>
+     <string>The left expression of the compound assignment uses uninitialized memory</string>
     </dict>
    </array>
-   <key>description</key><string>The left expression of the compound assignment is an uninitialized value. The computed value will also be garbage</string>
+   <key>description</key><string>The left expression of the compound assignment uses uninitialized memory</string>
    <key>category</key><string>Logic error</string>
-   <key>type</key><string>Assigned value is garbage or undefined</string>
+   <key>type</key><string>Assigned value is uninitialized</string>
    <key>check_name</key><string>core.uninitialized.Assign</string>
    <!-- This hash is experimental and going to change! -->
-   <key>issue_hash_content_of_line_in_context</key><string>025372576cd3ba6716044f93a51c978c</string>
+   <key>issue_hash_content_of_line_in_context</key><string>324827600c298776167cd9562f71bda6</string>
   <key>issue_context_kind</key><string>function</string>
   <key>issue_context</key><string>test_objc_fast_enumeration_2</string>
   <key>issue_hash_function_offset</key><string>5</string>

clang/test/Analysis/Inputs/expected-plists/plist-output.m.plist

@@ -5864,17 +5864,17 @@
      </array>
      <key>depth</key><integer>0</integer>
      <key>extended_message</key>
-     <string>The left expression of the compound assignment is an uninitialized value. The computed value will also be garbage</string>
+     <string>The left expression of the compound assignment uses uninitialized memory</string>
      <key>message</key>
-     <string>The left expression of the compound assignment is an uninitialized value. The computed value will also be garbage</string>
+     <string>The left expression of the compound assignment uses uninitialized memory</string>
     </dict>
    </array>
-   <key>description</key><string>The left expression of the compound assignment is an uninitialized value. The computed value will also be garbage</string>
+   <key>description</key><string>The left expression of the compound assignment uses uninitialized memory</string>
    <key>category</key><string>Logic error</string>
-   <key>type</key><string>Assigned value is garbage or undefined</string>
+   <key>type</key><string>Assigned value is uninitialized</string>
    <key>check_name</key><string>core.uninitialized.Assign</string>
    <!-- This hash is experimental and going to change! -->
-   <key>issue_hash_content_of_line_in_context</key><string>21c774309bdfd487c3d09a61a671bbcc</string>
+   <key>issue_hash_content_of_line_in_context</key><string>faa8858031ed123ff98cc23cf14d462f</string>
   <key>issue_context_kind</key><string>function</string>
   <key>issue_context</key><string>test_loop_fast_enumeration</string>
   <key>issue_hash_function_offset</key><string>5</string>

clang/test/Analysis/a_flaky_crash.cpp

@@ -14,7 +14,7 @@ bool bar(S);
 void foo() {
   int x;
   if (true && bar(S()))
-    ++x; // expected-warning{{The expression is an uninitialized value. The computed value will also be garbage}}
+    ++x; // expected-warning{{The expression uses uninitialized memory}}
 }
 
 // 256 copies of the same run-line to make it crash more often when it breaks.

clang/test/Analysis/analysis-after-multiple-dtors.cpp

@@ -23,6 +23,6 @@ int main() {
 
   int x;
   int y = x;
-  // expected-warning@-1{{Assigned value is garbage or undefined}}
+  // expected-warning@-1{{Assigned value is uninitialized}}
   (void)y;
 }

clang/test/Analysis/array-init-loop.cpp

@@ -19,7 +19,7 @@ void array_uninit() {
 
   auto [a, b, c, d, e] = arr;
 
-  int x = e; // expected-warning{{Assigned value is garbage or undefined}}
+  int x = e; // expected-warning{{Assigned value is uninitialized}}
 }
 
 void lambda_init() {
@@ -168,7 +168,7 @@ struct S3_duplicate {
 void array_uninit_non_pod() {
   S3 arr[1];
 
-  auto [a] = arr; // expected-warning@159{{ in implicit constructor is garbage or undefined }}
+  auto [a] = arr; // expected-warning@159{{ in implicit constructor is uninitialized}}
 }
 
 void lambda_init_non_pod() {
@@ -191,7 +191,7 @@ void lambda_init_non_pod() {
 void lambda_uninit_non_pod() {
   S3_duplicate arr[4];
 
-  int l = [arr] { return arr[3].i; }(); // expected-warning@164{{ in implicit constructor is garbage or undefined }}
+  int l = [arr] { return arr[3].i; }(); // expected-warning@164{{ in implicit constructor is uninitialized }}
 }
 
 // If this struct is being copy/move constructed by the implicit ctors, ArrayInitLoopExpr

clang/test/Analysis/array-punned-region.c

@@ -20,7 +20,7 @@ void array_struct_bitfield_1() {
 int array_struct_bitfield_2() {
   BITFIELD_CAST ff = {0};
   BITFIELD_CAST *pff = &ff;
-  int a = *((int *)pff + 2); // expected-warning{{Assigned value is garbage or undefined [core.uninitialized.Assign]}}
+  int a = *((int *)pff + 2); // expected-warning{{Assigned value is uninitialized [core.uninitialized.Assign]}}
   return a;
 }
 

clang/test/Analysis/builtin_overflow_notes.c

@@ -23,8 +23,8 @@ void test_overflow_note(int a, int b)
 
    if (__builtin_add_overflow(a, b, &res)) { // expected-note {{Assuming overflow}}
                                              // expected-note@-1 {{Taking true branch}}
-     int var = res; // expected-warning{{Assigned value is garbage or undefined}}
-                    // expected-note@-1 {{Assigned value is garbage or undefined}}
+     int var = res; // expected-warning{{Assigned value is uninitialized}}
+                    // expected-note@-1 {{Assigned value is uninitialized}}
      return;
    }
 }

clang/test/Analysis/call-invalidation.cpp

@@ -197,7 +197,7 @@ int testStdCtorDoesNotInvalidateParentObject() {
 int testStdCtorDoesNotInvalidateParentObjectSwapped() {
   StdWrappingOpaqueSwapped obj;
   int x = obj.o.nested_member; // no-garbage: std::Opaque::ctor might initialized this
-  int y = obj.uninit; // expected-warning {{Assigned value is garbage or undefined}}
+  int y = obj.uninit; // expected-warning {{Assigned value is uninitialized}}
   return x + y;
 }
 
@@ -277,6 +277,6 @@ struct StdWrappingFancyOpaque {
 int testNestedStdNamespacesAndRecords() {
   StdWrappingFancyOpaque obj;
   int x = obj.o.nested_member; // no-garbage: ctor
-  int y = obj.uninit; // expected-warning {{Assigned value is garbage or undefined}}
+  int y = obj.uninit; // expected-warning {{Assigned value is uninitialized}}
   return x + y;
 }

clang/test/Analysis/ctor-array.cpp

@@ -12,19 +12,19 @@ struct s {
 void a1(void) {
   s arr[3];
   int x = arr[0].x;
-  // expected-warning@-1{{Assigned value is garbage or undefined}}
+  // expected-warning@-1{{Assigned value is uninitialized}}
 }
 
 void a2(void) {
   s arr[3];
   int x = arr[1].x;
-  // expected-warning@-1{{Assigned value is garbage or undefined}}
+  // expected-warning@-1{{Assigned value is uninitialized}}
 }
 
 void a3(void) {
   s arr[3];
   int x = arr[2].x;
-  // expected-warning@-1{{Assigned value is garbage or undefined}}
+  // expected-warning@-1{{Assigned value is uninitialized}}
 }
 
 struct s2 {
@@ -37,23 +37,23 @@ void b1(void) {
 
   clang_analyzer_eval(arr[0].y == 2); // expected-warning{{TRUE}}
   int x = arr[0].x;
-  // expected-warning@-1{{Assigned value is garbage or undefined}}
+  // expected-warning@-1{{Assigned value is uninitialized}}
 }
 
 void b2(void) {
   s2 arr[3];
 
   clang_analyzer_eval(arr[1].y == 2); // expected-warning{{TRUE}}
   int x = arr[1].x;
-  // expected-warning@-1{{Assigned value is garbage or undefined}}
+  // expected-warning@-1{{Assigned value is uninitialized}}
 }
 
 void b3(void) {
   s2 arr[3];
 
   clang_analyzer_eval(arr[2].y == 2); // expected-warning{{TRUE}}
   int x = arr[2].x;
-  // expected-warning@-1{{Assigned value is garbage or undefined}}
+  // expected-warning@-1{{Assigned value is uninitialized}}
 }
 
 void c1(void) {
@@ -70,7 +70,7 @@ void c1(void) {
 
     clang_analyzer_eval(arr[1].y == 2); // expected-warning{{TRUE}}
     int x = arr[1].x;
-    // expected-warning@-1{{Assigned value is garbage or undefined}}
+    // expected-warning@-1{{Assigned value is uninitialized}}
   }
 }
 
@@ -100,15 +100,15 @@ void e1(void) {
   clang_analyzer_eval(arr[1].arr[1].y == 2); // expected-warning{{TRUE}}
 
   int x = arr[1].sarr[1].x;
-  // expected-warning@-1{{Assigned value is garbage or undefined}}
+  // expected-warning@-1{{Assigned value is uninitialized}}
 }
 
 void f1(void) {
   s2 arr[2][2];
 
   clang_analyzer_eval(arr[1][1].y == 2); // expected-warning{{TRUE}}
   int x = arr[1][1].x;
-  // expected-warning@-1{{Assigned value is garbage or undefined}}
+  // expected-warning@-1{{Assigned value is uninitialized}}
 }
 
 struct s5 {
@@ -168,14 +168,14 @@ void h2(void) {
   s a[2][2], b[2][2];
 
   int x = a[1][1].x;
-  // expected-warning@-1{{Assigned value is garbage or undefined}}
+  // expected-warning@-1{{Assigned value is uninitialized}}
 }
 
 void h3(void) {
   s a[2][2], b[2][2];
 
   int x = b[1][1].y;
-  // expected-warning@-1{{Assigned value is garbage or undefined}}
+  // expected-warning@-1{{Assigned value is uninitialized}}
 }
 
 struct Base {