[clang] 2d6829b - [clang] disable implicit moves when not in CPlusPLus
Matheus Izvekov via cfe-commits
cfe-commits at lists.llvm.org
Tue Sep 14 02:29:56 PDT 2021
Author: Matheus Izvekov
Date: 2021-09-14T11:29:47+02:00
New Revision: 2d6829bbbe6877920d9be1db93b9f3fc85b43d10
URL: https://github.com/llvm/llvm-project/commit/2d6829bbbe6877920d9be1db93b9f3fc85b43d10
DIFF: https://github.com/llvm/llvm-project/commit/2d6829bbbe6877920d9be1db93b9f3fc85b43d10.diff
LOG: [clang] disable implicit moves when not in CPlusPLus
See PR51842.
This fixes an assert firing in the static analyzer, triggered by implicit moves
in blocks in C mode:
This also simplifies the AST a little bit when compiling non C++ code,
as the xvalue implicit casts are not inserted.
We keep and test that the nrvo flag is still being set on the VarDecls,
as that is still a bit beneficial while not really making anything
more complicated.
Signed-off-by: Matheus Izvekov <mizvekov at gmail.com>
Reviewed By: NoQ
Differential Revision: https://reviews.llvm.org/D109654
Added:
clang/test/AST/nrvo.c
clang/test/Analysis/blocks-nrvo.c
Modified:
clang/lib/Sema/SemaStmt.cpp
Removed:
################################################################################
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index dc93e9e1c51c5..813925460241e 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -3481,7 +3481,8 @@ VerifyInitializationSequenceCXX98(const Sema &S,
ExprResult Sema::PerformMoveOrCopyInitialization(
const InitializedEntity &Entity, const NamedReturnInfo &NRInfo, Expr *Value,
bool SupressSimplerImplicitMoves) {
- if ((!getLangOpts().CPlusPlus2b || SupressSimplerImplicitMoves) &&
+ if (getLangOpts().CPlusPlus &&
+ (!getLangOpts().CPlusPlus2b || SupressSimplerImplicitMoves) &&
NRInfo.isMoveEligible()) {
ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, Value->getType(),
CK_NoOp, Value, VK_XValue, FPOptionsOverride());
diff --git a/clang/test/AST/nrvo.c b/clang/test/AST/nrvo.c
new file mode 100644
index 0000000000000..4f50d6a1e384b
--- /dev/null
+++ b/clang/test/AST/nrvo.c
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -ast-dump -fblocks %s | FileCheck -strict-whitespace %s
+
+struct A {};
+
+struct A f1() {
+ // CHECK: FunctionDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:1, line:{{[^:]*}}:1> line:[[@LINE-1]]:10 f1 'struct A ()'
+ // CHECK-NEXT: CompoundStmt 0x{{[^ ]*}} <col:15, line:{{[^:]*}}:1>
+ struct A a;
+ // CHECK-NEXT: DeclStmt 0x{{[^ ]*}} <line:[[@LINE-1]]:3, col:13>
+ // CHECK-NEXT: VarDecl 0x{{[^ ]*}} <col:3, col:12> col:12 used a 'struct A':'struct A' nrvo
+ return a;
+ // CHECK-NEXT: ReturnStmt 0x{{[^ ]*}} <line:[[@LINE-1]]:3, col:10>
+ // CHECK-NEXT: ImplicitCastExpr 0x{{[^ ]*}} <col:10> 'struct A':'struct A' <LValueToRValue>
+ // CHECK-NEXT: DeclRefExpr 0x{{[^ ]*}} <col:10> 'struct A':'struct A' lvalue Var 0x{{[^ ]*}} 'a' 'struct A':'struct A'
+}
+
+void f2() {
+ (void)^{
+ // CHECK: BlockDecl 0x{{[^ ]*}} <line:[[@LINE-1]]:9, line:{{[^:]*}}:3> line:[[@LINE-1]]:9
+ // CHECK-NEXT: CompoundStmt 0x{{[^ ]*}} <col:10, line:{{[^:]*}}:3>
+ struct A a;
+ // CHECK-NEXT: DeclStmt 0x{{[^ ]*}} <line:[[@LINE-1]]:5, col:15>
+ // CHECK-NEXT: VarDecl 0x{{[^ ]*}} <col:5, col:14> col:14 used a 'struct A':'struct A' nrvo
+ return a;
+ // CHECK-NEXT: ReturnStmt 0x{{[^ ]*}} <line:[[@LINE-1]]:5, col:12>
+ // CHECK-NEXT: ImplicitCastExpr 0x{{[^ ]*}} <col:12> 'struct A':'struct A' <LValueToRValue>
+ // CHECK-NEXT: DeclRefExpr 0x{{[^ ]*}} <col:12> 'struct A':'struct A' lvalue Var 0x{{[^ ]*}} 'a' 'struct A':'struct A'
+ }();
+}
diff --git a/clang/test/Analysis/blocks-nrvo.c b/clang/test/Analysis/blocks-nrvo.c
new file mode 100644
index 0000000000000..bb0be869ee767
--- /dev/null
+++ b/clang/test/Analysis/blocks-nrvo.c
@@ -0,0 +1,14 @@
+// RUN: %clang_analyze_cc1 -w -analyzer-checker=core -fblocks -verify %s
+
+// expected-no-diagnostics
+
+typedef struct {
+ int x;
+} S;
+
+void foo() {
+ ^{
+ S s;
+ return s; // no-crash
+ };
+}
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