[clang][Interp] Pointers into unknown-size arrays are never one-past-end

tbaederr · AlexisPerry · commit 9e94606f1531 · 2024-06-27T15:52:23.000-06:00
diff --git a/clang/lib/AST/Interp/Pointer.h b/clang/lib/AST/Interp/Pointer.h
@@ -553,6 +553,9 @@ class Pointer {
     if (!asBlockPointer().Pointee)
       return false;
 
+    if (isUnknownSizeArray())
+      return false;
+
     return isElementPastEnd() ||
            (getSize() == getOffset() && !isZeroSizeArray());
   }
diff --git a/clang/test/AST/Interp/arrays.cpp b/clang/test/AST/Interp/arrays.cpp
@@ -626,3 +626,4 @@ constexpr int *get2() {
   extern int same_entity_2[];
   return same_entity_2;
 }
+static_assert(get2() == same_entity_2, "failed to find previous decl");

Original file line number	Diff line number	Diff line change
`@@ -553,6 +553,9 @@ class Pointer {`
`553`	`553`	`if (!asBlockPointer().Pointee)`
`554`	`554`	`return false;`
`555`	`555`
	`556`	`+ if (isUnknownSizeArray())`
	`557`	`+ return false;`
	`558`	`+`
`556`	`559`	`return isElementPastEnd() \|\|`
`557`	`560`	`(getSize() == getOffset() && !isZeroSizeArray());`
`558`	`561`	`}`
Original file line number	Diff line number	Diff line change
`@@ -626,3 +626,4 @@ constexpr int *get2() {`
`626`	`626`	`extern int same_entity_2[];`
`627`	`627`	`return same_entity_2;`
`628`	`628`	`}`
	`629`	`+static_assert(get2() == same_entity_2, "failed to find previous decl");`