[clang][Interp] Fix "Initializing" zero-size arrays

getIndex() returns 0 here, so we were trying to initalize the 0th element. Fixes #88018
llvm · Apr 9, 2024 · d412047 · d412047
1 parent 62e9257
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diff --git a/clang/lib/AST/Interp/Pointer.cpp b/clang/lib/AST/Interp/Pointer.cpp
@@ -177,6 +177,10 @@ void Pointer::initialize() const {
     if (isStatic() && Base == 0)
       return;
 
+    // Nothing to do for these.
+    if (Desc->getNumElems() == 0)
+      return;
+
     InitMapPtr &IM = getInitMap();
     if (!IM)
       IM =

diff --git a/clang/test/AST/Interp/arrays.cpp b/clang/test/AST/Interp/arrays.cpp
@@ -566,3 +566,7 @@ char melchizedek[2200000000];
 typedef decltype(melchizedek[1] - melchizedek[0]) ptrdiff_t;
 constexpr ptrdiff_t d1 = &melchizedek[0x7fffffff] - &melchizedek[0]; // ok
 constexpr ptrdiff_t d3 = &melchizedek[0] - &melchizedek[0x80000000u]; // ok
+
+/// GH#88018
+const int SZA[] = {};
+void testZeroSizedArrayAccess() { unsigned c = SZA[4]; }