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[clang][bytecode] Reject memcpy dummy pointers after null check #118460

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Merged
merged 1 commit into from
Dec 3, 2024
Merged

[clang][bytecode] Reject memcpy dummy pointers after null check #118460

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7 changes: 4 additions & 3 deletions clang/lib/AST/ByteCode/InterpBuiltin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1813,9 +1813,6 @@ static bool interp__builtin_memcpy(InterpState &S, CodePtr OpPC,

bool Move = (ID == Builtin::BI__builtin_memmove || ID == Builtin::BImemmove);

if (DestPtr.isDummy() || SrcPtr.isDummy())
return false;

// If the size is zero, we treat this as always being a valid no-op.
if (Size.isZero()) {
S.Stk.push<Pointer>(DestPtr);
Expand All @@ -1830,6 +1827,10 @@ static bool interp__builtin_memcpy(InterpState &S, CodePtr OpPC,
return false;
}

// As a last resort, reject dummy pointers.
if (DestPtr.isDummy() || SrcPtr.isDummy())
return false;

if (!DoBitCastPtr(S, OpPC, SrcPtr, DestPtr))
return false;

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4 changes: 4 additions & 0 deletions clang/test/AST/ByteCode/builtin-functions.cpp
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Expand Up @@ -1169,6 +1169,10 @@ namespace BuiltinMemcpy {
static_assert(__builtin_memcpy(null_incomplete, null_incomplete, sizeof(wchar_t))); // both-error {{not an integral constant expression}} \
// both-note {{source of 'memcpy' is nullptr}}

wchar_t global;
constexpr wchar_t *null = 0;
static_assert(__builtin_memcpy(&global, null, sizeof(wchar_t))); // both-error {{not an integral constant expression}} \
// both-note {{source of 'memcpy' is nullptr}}

constexpr int simpleMove() {
int a = 12;
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