[clang] d267daa - [clang][bytecode] Diagnose loads from weak variables (#109256)
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Thu Sep 19 02:59:41 PDT 2024
Author: Timm Baeder
Date: 2024-09-19T11:59:38+02:00
New Revision: d267daa9eb517b2e040a59121c15dba59223ebba
URL: https://github.com/llvm/llvm-project/commit/d267daa9eb517b2e040a59121c15dba59223ebba
DIFF: https://github.com/llvm/llvm-project/commit/d267daa9eb517b2e040a59121c15dba59223ebba.diff
LOG: [clang][bytecode] Diagnose loads from weak variables (#109256)
Added:
Modified:
clang/lib/AST/ByteCode/Interp.cpp
clang/test/AST/ByteCode/weak.cpp
clang/test/SemaCXX/weak-init.cpp
Removed:
################################################################################
diff --git a/clang/lib/AST/ByteCode/Interp.cpp b/clang/lib/AST/ByteCode/Interp.cpp
index 827a177f9bf830..17cf3ccdeb6a94 100644
--- a/clang/lib/AST/ByteCode/Interp.cpp
+++ b/clang/lib/AST/ByteCode/Interp.cpp
@@ -560,13 +560,25 @@ bool CheckGlobalInitialized(InterpState &S, CodePtr OpPC, const Pointer &Ptr) {
return false;
}
+static bool CheckWeak(InterpState &S, CodePtr OpPC, const Pointer &Ptr) {
+ if (!Ptr.isWeak())
+ return true;
+
+ const auto *VD = Ptr.getDeclDesc()->asVarDecl();
+ assert(VD);
+ S.FFDiag(S.Current->getLocation(OpPC), diag::note_constexpr_var_init_weak)
+ << VD;
+ S.Note(VD->getLocation(), diag::note_declared_at);
+
+ return false;
+}
+
bool CheckLoad(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
AccessKinds AK) {
if (!CheckLive(S, OpPC, Ptr, AK))
return false;
if (!CheckConstant(S, OpPC, Ptr))
return false;
-
if (!CheckDummy(S, OpPC, Ptr, AK))
return false;
if (!CheckExtern(S, OpPC, Ptr))
@@ -579,6 +591,8 @@ bool CheckLoad(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
return false;
if (!CheckTemporary(S, OpPC, Ptr, AK))
return false;
+ if (!CheckWeak(S, OpPC, Ptr))
+ return false;
if (!CheckMutable(S, OpPC, Ptr))
return false;
if (!CheckVolatile(S, OpPC, Ptr, AK))
diff --git a/clang/test/AST/ByteCode/weak.cpp b/clang/test/AST/ByteCode/weak.cpp
index 0322241beef83b..52c75229d9ec7a 100644
--- a/clang/test/AST/ByteCode/weak.cpp
+++ b/clang/test/AST/ByteCode/weak.cpp
@@ -7,3 +7,11 @@ int ha[(bool)&a]; // both-warning {{variable length arrays in C++ are a Clang ex
int ha2[&a == nullptr]; // both-warning {{variable length arrays in C++ are a Clang extension}} \
// both-note {{comparison against address of weak declaration '&a' can only be performed at runtime}} \
// both-error {{variable length array declaration not allowed at file scope}}
+
+extern const int W1 __attribute__((weak)) = 10; // both-note {{declared here}}
+static_assert(W1 == 10, ""); // both-error {{static assertion expression is not an integral constant expression}} \
+ // both-note {{initializer of weak variable 'W1' is not considered constant because it may be
diff erent at runtime}}
+
+extern const int W2 __attribute__((weak)); // both-note {{declared here}}
+static_assert(W2 == 10, ""); // both-error {{static assertion expression is not an integral constant expression}} \
+ // both-note {{initializer of 'W2' is unknown}}
diff --git a/clang/test/SemaCXX/weak-init.cpp b/clang/test/SemaCXX/weak-init.cpp
index a88d32bdca5a17..0147b80f382402 100644
--- a/clang/test/SemaCXX/weak-init.cpp
+++ b/clang/test/SemaCXX/weak-init.cpp
@@ -1,4 +1,5 @@
// RUN: %clang_cc1 %s -verify -fsyntax-only
+// RUN: %clang_cc1 %s -verify -fsyntax-only -fexperimental-new-constant-interpreter
extern const int W1 __attribute__((weak)) = 10; // expected-note {{declared here}}
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