[analyzer] use invalidateRegions() in VisitGCCAsmStmt (#109838)

Author: pskrgag

clang/lib/StaticAnalyzer/Core/ExprEngine.cpp

@@ -3811,15 +3811,19 @@ void ExprEngine::VisitGCCAsmStmt(const GCCAsmStmt *A, ExplodedNode *Pred,
     assert(!isa<NonLoc>(X)); // Should be an Lval, or unknown, undef.
 
     if (std::optional<Loc> LV = X.getAs<Loc>())
-      state = state->bindLoc(*LV, UnknownVal(), Pred->getLocationContext());
+      state = state->invalidateRegions(*LV, A, currBldrCtx->blockCount(),
+                                       Pred->getLocationContext(),
+                                       /*CausedByPointerEscape=*/true);
   }
 
   // Do not reason about locations passed inside inline assembly.
   for (const Expr *I : A->inputs()) {
     SVal X = state->getSVal(I, Pred->getLocationContext());
 
     if (std::optional<Loc> LV = X.getAs<Loc>())
-      state = state->bindLoc(*LV, UnknownVal(), Pred->getLocationContext());
+      state = state->invalidateRegions(*LV, A, currBldrCtx->blockCount(),
+                                       Pred->getLocationContext(),
+                                       /*CausedByPointerEscape=*/true);
   }
 
   Bldr.generateNode(A, Pred, state);

clang/test/Analysis/asm.cpp

@@ -7,11 +7,10 @@ void clang_analyzer_dump_ptr(void *);
 
 int global;
 void testRValueOutput() {
-  int &ref = global;
-  ref = 1;
+  int origVal = global;
   __asm__("" : "=r"(((int)(global))));  // don't crash on rvalue output operand
-  clang_analyzer_eval(global == 1); // expected-warning{{UNKNOWN}}
-  clang_analyzer_eval(ref == 1);    // expected-warning{{UNKNOWN}}
+  int newVal = global; // Value "after" the invalidation.
+  clang_analyzer_eval(origVal == newVal); // expected-warning{{TRUE}} expected-warning{{FALSE}}
 }
 
 void *MyMemcpy(void *d, const void *s, const int n) {
@@ -40,7 +39,20 @@ void testInlineAsmMemcpyUninit(void)
 {
     int a[10], b[10] = {}, c;
     MyMemcpy(&a[1], &b[1], sizeof(b) - sizeof(b[1]));
-    c = a[0]; // expected-warning{{Assigned value is garbage or undefined}}
+    c = a[0]; // FIXME: should be warning about uninitialized value, but invalidateRegions() also
+              // invalidates super region.
+}
+
+void testInlineAsmMemcpyUninitLoop(const void *src, unsigned long len)
+{
+    int a[10], c;
+    unsigned long toCopy = sizeof(a) < len ? sizeof(a) : len;
+
+    MyMemcpy(a, src, toCopy);
+
+    // Use index 1, since before use of invalidateRegions in VisitGCCAsmStmt, engine bound unknown SVal only to
+    // first element.
+    c = a[1]; // no-warning
 }
 
 void testAsmWithVoidPtrArgument()
@@ -49,6 +61,6 @@ void testAsmWithVoidPtrArgument()
   clang_analyzer_dump(*(int *)globalVoidPtr); // expected-warning-re {{reg_${{[0-9]+}}<int Element{SymRegion{reg_${{[0-9]+}}<void * globalVoidPtr>},0 S64b,int}>}}
   clang_analyzer_dump_ptr(globalVoidPtr); // expected-warning-re {{&SymRegion{reg_${{[0-9]+}}<void * globalVoidPtr>}}}
   asm ("" : : "a"(globalVoidPtr)); // no crash
-  clang_analyzer_dump(*(int *)globalVoidPtr); // expected-warning {{Unknown}}
+  clang_analyzer_dump(*(int *)globalVoidPtr); // expected-warning {{derived_}}
   clang_analyzer_dump_ptr(globalVoidPtr); // expected-warning-re {{&SymRegion{reg_${{[0-9]+}}<void * globalVoidPtr>}}}
 }