samitolvanen updated this revision to Diff 383518.
samitolvanen marked 2 inline comments as done.
samitolvanen added a comment.
Missed a comment.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D108479/new/
https://reviews.llvm.org/D108479
Files:
clang/docs/LanguageExtensions.rst
clang/include/clang/AST/APValue.h
clang/include/clang/Basic/Builtins.def
clang/lib/AST/APValue.cpp
clang/lib/AST/ExprConstant.cpp
clang/lib/CodeGen/CGBuiltin.cpp
clang/lib/CodeGen/CGExprConstant.cpp
clang/lib/Sema/SemaChecking.cpp
clang/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp
clang/test/CodeGen/builtin-addressof-nocfi.c
clang/test/SemaCXX/builtins.cpp
Index: clang/test/SemaCXX/builtins.cpp
===================================================================
--- clang/test/SemaCXX/builtins.cpp
+++ clang/test/SemaCXX/builtins.cpp
@@ -39,6 +39,15 @@
S *ptmp = __builtin_addressof(S{}); // expected-error {{taking the address of a temporary}}
}
+namespace addressof_nocfi {
+void a(void) {}
+static_assert(__builtin_addressof_nocfi(a) == a, "");
+
+struct S {
+} s;
+static_assert(__builtin_addressof_nocfi(s) == &s, "");
+} // namespace addressof_nocfi
+
void no_ms_builtins() {
__assume(1); // expected-error {{use of undeclared}}
__noop(1); // expected-error {{use of undeclared}}
Index: clang/test/CodeGen/builtin-addressof-nocfi.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/builtin-addressof-nocfi.c
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fsanitize=cfi-icall -o - %s | FileCheck %s
+
+#if !__has_builtin(__builtin_addressof_nocfi)
+#error "missing __builtin_addressof_nocfi"
+#endif
+
+void a(void) {}
+void b(void) {}
+void c(void (*p)(void)) {
+ p();
+}
+
+// CHECK: @e = constant void ()* no_cfi @a
+void (*const e)(void) = __builtin_addressof_nocfi(a);
+// CHECK: @f = global [2 x void ()*] [void ()* @b, void ()* no_cfi @b]
+void (*f[])(void) = {b, __builtin_addressof_nocfi(b)};
+
+void d(void) {
+ // CHECK: store void ()* no_cfi @b, void ()** %g
+ void (*g)(void) = __builtin_addressof_nocfi(b);
+ // CHECK: call void @c(void ()* no_cfi @a)
+ c(__builtin_addressof_nocfi(a));
+ e();
+ f[1]();
+ g();
+}
Index: clang/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp
@@ -66,7 +66,8 @@
case Builtin::BI__builtin_expect:
case Builtin::BI__builtin_expect_with_probability:
case Builtin::BI__builtin_assume_aligned:
- case Builtin::BI__builtin_addressof: {
+ case Builtin::BI__builtin_addressof:
+ case Builtin::BI__builtin_addressof_nocfi: {
// For __builtin_unpredictable, __builtin_expect,
// __builtin_expect_with_probability and __builtin_assume_aligned,
// just return the value of the subexpression.
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -1749,6 +1749,7 @@
return ExprError();
break;
case Builtin::BI__builtin_addressof:
+ case Builtin::BI__builtin_addressof_nocfi:
if (SemaBuiltinAddressof(*this, TheCall))
return ExprError();
break;
Index: clang/lib/CodeGen/CGExprConstant.cpp
===================================================================
--- clang/lib/CodeGen/CGExprConstant.cpp
+++ clang/lib/CodeGen/CGExprConstant.cpp
@@ -1889,8 +1889,12 @@
if (D->hasAttr<WeakRefAttr>())
return CGM.GetWeakRefReference(D).getPointer();
- if (auto FD = dyn_cast<FunctionDecl>(D))
- return CGM.GetAddrOfFunction(FD);
+ if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
+ llvm::Constant *C = CGM.GetAddrOfFunction(FD);
+ if (base.isNoCFIValue())
+ return llvm::NoCFIValue::get(cast<llvm::GlobalValue>(C));
+ return C;
+ }
if (auto VD = dyn_cast<VarDecl>(D)) {
// We can never refer to a variable with local storage.
Index: clang/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- clang/lib/CodeGen/CGBuiltin.cpp
+++ clang/lib/CodeGen/CGBuiltin.cpp
@@ -4439,6 +4439,9 @@
}
case Builtin::BI__builtin_addressof:
return RValue::get(EmitLValue(E->getArg(0)).getPointer(*this));
+ case Builtin::BI__builtin_addressof_nocfi:
+ return RValue::get(llvm::NoCFIValue::get(
+ cast<GlobalValue>(EmitLValue(E->getArg(0)).getPointer(*this))));
case Builtin::BI__builtin_operator_new:
return EmitBuiltinNewDeleteCall(
E->getCallee()->getType()->castAs<FunctionProtoType>(), E, false);
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -8982,6 +8982,11 @@
switch (BuiltinOp) {
case Builtin::BI__builtin_addressof:
return evaluateLValue(E->getArg(0), Result);
+ case Builtin::BI__builtin_addressof_nocfi:
+ if (!evaluateLValue(E->getArg(0), Result))
+ return false;
+ Result.Base.setNoCFIValue(true);
+ return true;
case Builtin::BI__builtin_assume_aligned: {
// We need to be very careful here because: if the pointer does not have the
// asserted alignment, then the behavior is undefined, and undefined
Index: clang/lib/AST/APValue.cpp
===================================================================
--- clang/lib/AST/APValue.cpp
+++ clang/lib/AST/APValue.cpp
@@ -40,9 +40,11 @@
"Type is insufficiently aligned");
APValue::LValueBase::LValueBase(const ValueDecl *P, unsigned I, unsigned V)
- : Ptr(P ? cast<ValueDecl>(P->getCanonicalDecl()) : nullptr), Local{I, V} {}
+ : Ptr(P ? cast<ValueDecl>(P->getCanonicalDecl()) : nullptr),
+ Local{I, V,
+ /*NoCFIValue =*/false} {}
APValue::LValueBase::LValueBase(const Expr *P, unsigned I, unsigned V)
- : Ptr(P), Local{I, V} {}
+ : Ptr(P), Local{I, V, /*NoCFIValue=*/false} {}
APValue::LValueBase APValue::LValueBase::getDynamicAlloc(DynamicAllocLValue LV,
QualType Type) {
@@ -124,6 +126,15 @@
return QualType::getFromOpaquePtr(DynamicAllocType);
}
+bool APValue::LValueBase::isNoCFIValue() const {
+ return (is<const ValueDecl *>() ? Local.NoCFIValue : false);
+}
+
+void APValue::LValueBase::setNoCFIValue(bool NoCFI) {
+ if (is<const ValueDecl *>())
+ Local.NoCFIValue = NoCFI;
+}
+
void APValue::LValueBase::Profile(llvm::FoldingSetNodeID &ID) const {
ID.AddPointer(Ptr.getOpaqueValue());
if (is<TypeInfoLValue>() || is<DynamicAllocLValue>())
Index: clang/include/clang/Basic/Builtins.def
===================================================================
--- clang/include/clang/Basic/Builtins.def
+++ clang/include/clang/Basic/Builtins.def
@@ -1559,6 +1559,7 @@
// Clang builtins (not available in GCC).
BUILTIN(__builtin_addressof, "v*v&", "nct")
+BUILTIN(__builtin_addressof_nocfi, "v*v&", "nct")
BUILTIN(__builtin_operator_new, "v*z", "tc")
BUILTIN(__builtin_operator_delete, "vv*", "tn")
BUILTIN(__builtin_char_memchr, "c*cC*iz", "n")
Index: clang/include/clang/AST/APValue.h
===================================================================
--- clang/include/clang/AST/APValue.h
+++ clang/include/clang/AST/APValue.h
@@ -176,6 +176,8 @@
unsigned getVersion() const;
QualType getTypeInfoType() const;
QualType getDynamicAllocType() const;
+ bool isNoCFIValue() const;
+ void setNoCFIValue(bool NoCFI);
QualType getType() const;
@@ -190,6 +192,7 @@
PtrTy Ptr;
struct LocalState {
unsigned CallIndex, Version;
+ bool NoCFIValue;
};
union {
LocalState Local;
Index: clang/docs/LanguageExtensions.rst
===================================================================
--- clang/docs/LanguageExtensions.rst
+++ clang/docs/LanguageExtensions.rst
@@ -2517,6 +2517,13 @@
return __builtin_addressof(value);
}
+``__builtin_addressof_nocfi``
+-----------------------------
+
+``__builtin_addressof_nocfi`` is similar to ``__builtin_addressof``, but
+with ``-fsanitize=cfi``, when passed a function, it returns the address of
+the function body instead of a pointer to the CFI jump table.
+
``__builtin_operator_new`` and ``__builtin_operator_delete``
------------------------------------------------------------
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