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[clang][bytecode] Guard strcmp against differing element types (#154777)

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This can happen when casts are involved.

Fixes #154006
This commit is contained in:
Timm Baeder 2025-08-21 18:02:08 +02:00 committed by GitHub
parent dacabc1fee
commit 3923adfa3f
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2 changed files with 15 additions and 1 deletions
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7
clang/lib/AST/ByteCode/InterpBuiltin.cpp
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@ -205,6 +205,8 @@ static bool interp__builtin_strcmp(InterpState &S, CodePtr OpPC,
if (A.isDummy() || B.isDummy()) if (A.isDummy() || B.isDummy())
return false; return false;
if (!A.isBlockPointer() || !B.isBlockPointer())
return false;
bool IsWide = ID == Builtin::BIwcscmp || ID == Builtin::BIwcsncmp || bool IsWide = ID == Builtin::BIwcscmp || ID == Builtin::BIwcsncmp ||
ID == Builtin::BI__builtin_wcscmp || ID == Builtin::BI__builtin_wcscmp ||
@ -212,7 +214,10 @@ static bool interp__builtin_strcmp(InterpState &S, CodePtr OpPC,
assert(A.getFieldDesc()->isPrimitiveArray()); assert(A.getFieldDesc()->isPrimitiveArray());
assert(B.getFieldDesc()->isPrimitiveArray()); assert(B.getFieldDesc()->isPrimitiveArray());
assert(getElemType(A).getTypePtr() == getElemType(B).getTypePtr()); // Different element types shouldn't happen, but with casts they can.
if (!S.getASTContext().hasSameUnqualifiedType(getElemType(A), getElemType(B)))
return false;
PrimType ElemT = *S.getContext().classify(getElemType(A)); PrimType ElemT = *S.getContext().classify(getElemType(A));
auto returnResult = [&](int V) -> bool { auto returnResult = [&](int V) -> bool {

9
clang/test/AST/ByteCode/c.c
View File

@ -338,3 +338,12 @@ static void *FooTable[1] = {
} }
}; };
int strcmp(const char *, const char *); // all-note {{passing argument to parameter here}}
#define S "\x01\x02\x03\x04\x05\x06\x07\x08"
const char _str[] = {S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7]};
const unsigned char _str2[] = {S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7]};
const int compared = strcmp(_str, (const char *)_str2); // all-error {{initializer element is not a compile-time constant}}
const int compared2 = strcmp(strcmp, _str); // all-warning {{incompatible pointer types}} \
// all-error {{initializer element is not a compile-time constant}}