[clang][bytecode] Fix diagnosing reads from temporaries #106868
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Fix the DeclID not being set in global temporaries and use the same strategy for deciding if a temporary is readable as the current interpreter.
llvmbot
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clang
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@llvm/pr-subscribers-clang Author: Timm Baeder (tbaederr) ChangesFix the DeclID not being set in global temporaries and use the same strategy for deciding if a temporary is readable as the current interpreter. Full diff: https://github.com/llvm/llvm-project/pull/106868.diff 3 Files Affected:
diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index dced9ea3493732..1ddaa5bd41df75 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -3772,7 +3772,6 @@ VarCreationState Compiler<Emitter>::visitVarDecl(const VarDecl *VD,
auto initGlobal = [&](unsigned GlobalIndex) -> bool {
assert(Init);
- DeclScope<Emitter> LocalScope(this, VD);
if (VarT) {
if (!this->visit(Init))
@@ -3796,6 +3795,8 @@ VarCreationState Compiler<Emitter>::visitVarDecl(const VarDecl *VD,
return this->emitPopPtr(Init);
};
+ DeclScope<Emitter> LocalScope(this, VD);
+
// We've already seen and initialized this global.
if (std::optional<unsigned> GlobalIndex = P.getGlobal(VD)) {
if (P.getPtrGlobal(*GlobalIndex).isInitialized())
diff --git a/clang/lib/AST/ByteCode/Interp.cpp b/clang/lib/AST/ByteCode/Interp.cpp
index 42012767c22332..3d75f2ce7183a6 100644
--- a/clang/lib/AST/ByteCode/Interp.cpp
+++ b/clang/lib/AST/ByteCode/Interp.cpp
@@ -181,16 +181,21 @@ static bool CheckTemporary(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
if (!Ptr.isStaticTemporary())
return true;
- if (Ptr.getDeclDesc()->getType().isConstQualified())
+ const auto *MTE = dyn_cast_if_present<MaterializeTemporaryExpr>(
+ Ptr.getDeclDesc()->asExpr());
+ if (!MTE)
return true;
- if (S.P.getCurrentDecl() == ID)
- return true;
-
- const SourceInfo &E = S.Current->getSource(OpPC);
- S.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
- S.Note(Ptr.getDeclLoc(), diag::note_constexpr_temporary_here);
- return false;
+ // FIXME(perf): Since we do this check on every Load from a static
+ // temporary, it might make sense to cache the value of the
+ // isUsableInConstantExpressions call.
+ if (!MTE->isUsableInConstantExpressions(S.getASTContext()) &&
+ Ptr.block()->getEvalID() != S.Ctx.getEvalID()) {
+ const SourceInfo &E = S.Current->getSource(OpPC);
+ S.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
+ S.Note(Ptr.getDeclLoc(), diag::note_constexpr_temporary_here);
+ return false;
+ }
}
return true;
}
diff --git a/clang/test/AST/ByteCode/references.cpp b/clang/test/AST/ByteCode/references.cpp
index 9a790dc75d7308..7c1dccb1f9e341 100644
--- a/clang/test/AST/ByteCode/references.cpp
+++ b/clang/test/AST/ByteCode/references.cpp
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -verify %s
-// RUN: %clang_cc1 -verify=ref %s
+// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -verify=expected,both %s
+// RUN: %clang_cc1 -verify=ref,both %s
constexpr int a = 10;
@@ -135,3 +135,12 @@ static_assert(nonextended_string_ref[2] == '\0', "");
/// but taking its address is.
int &&A = 12;
int arr[!&A];
+
+namespace Temporaries {
+ struct A { int n; };
+ struct B { const A &a; };
+ const B j = {{1}}; // both-note {{temporary created here}}
+
+ static_assert(j.a.n == 1, ""); // both-error {{not an integral constant expression}} \
+ // both-note {{read of temporary is not allowed in a constant expression outside the expression that created the temporary}}
+}
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tbaederr
changed the title
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/66/builds/3334 Here is the relevant piece of the build log for the reference |
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Fix the DeclID not being set in global temporaries and use the same strategy for deciding if a temporary is readable as the current interpreter.