diff --git a/clang/lib/Checker/RegionStore.cpp b/clang/lib/Checker/RegionStore.cpp index b333a5d2830e..c97da33aaac6 100644 --- a/clang/lib/Checker/RegionStore.cpp +++ b/clang/lib/Checker/RegionStore.cpp @@ -787,9 +787,12 @@ DefinedOrUnknownSVal RegionStoreManager::getSizeInElements(const GRState *state, return ValMgr.makeIntVal(CAT->getSize(), false); } - // Clients can use ordinary variables as if they were arrays. These - // essentially are arrays of size 1. - return ValMgr.makeIntVal(1, false); + // Clients can reinterpret ordinary variables as arrays, possibly of + // another type. The width is rounded down to ensure that an access is + // entirely within bounds. + CharUnits VarSize = getContext().getTypeSizeInChars(T); + CharUnits EleSize = getContext().getTypeSizeInChars(EleTy); + return ValMgr.makeIntVal(VarSize / EleSize, false); } } diff --git a/clang/test/Analysis/no-outofbounds.c b/clang/test/Analysis/no-outofbounds.c index f9ac589797a8..771323b81114 100644 --- a/clang/test/Analysis/no-outofbounds.c +++ b/clang/test/Analysis/no-outofbounds.c @@ -1,6 +1,5 @@ // RUN: %clang_cc1 -analyzer-check-objc-mem -analyze -analyzer-experimental-internal-checks -analyzer-store=basic -verify %s // RUN: %clang_cc1 -analyzer-check-objc-mem -analyze -analyzer-experimental-internal-checks -analyzer-store=region -verify %s -// XFAIL: * //===----------------------------------------------------------------------===// // This file tests cases where we should not flag out-of-bounds warnings. @@ -10,4 +9,6 @@ void f() { long x = 0; char *y = (char*) &x; char c = y[0] + y[1] + y[2]; // no-warning + short *z = (short*) &x; + short s = z[0] + z[1]; // no-warning } diff --git a/clang/test/Analysis/outofbound.c b/clang/test/Analysis/outofbound.c index 45325e92f376..e1ff66ccf4dc 100644 --- a/clang/test/Analysis/outofbound.c +++ b/clang/test/Analysis/outofbound.c @@ -13,3 +13,26 @@ void f2() { int *p = malloc(12); p[3] = 4; // expected-warning{{Access out-of-bound array element (buffer overflow)}} } + +struct three_words { + int c[3]; +}; + +struct seven_words { + int c[7]; +}; + +void f3() { + struct three_words a, *p; + p = &a; + p[0] = a; // no-warning + p[1] = a; // expected-warning{{Access out-of-bound array element (buffer overflow)}} +} + +void f4() { + struct seven_words c; + struct three_words a, *p = (struct three_words *)&c; + p[0] = a; // no-warning + p[1] = a; // no-warning + p[2] = a; // expected-warning{{Access out-of-bound array element (buffer overflow)}} +}