ahatanak created this revision.
ahatanak added a reviewer: rsmith.
The assertion fails when a function with a default argument that materializes a
temporary is called more than once in an expression. The assertion fails in
CallStackFrame::createTemporary when it searches map Temporaries using the
default argument's expression (which is a MaterializeTemporaryExpr) as the key
and it discovers that there is already an element with that key that has been
initialized.
constexpr bool equals(const float& arg = 1.0f) {
return arg == 1.0f;
}
constexpr bool test_default_arg() {
return equals() && equals();
}
This patch removes the assertion and makes CallStackFrame::createTemporary
reset the existing element and return it if the element is found in the map.
rdar://problem/36505742
https://reviews.llvm.org/D42776
Files:
lib/AST/ExprConstant.cpp
test/SemaCXX/constexpr-default-arg.cpp
Index: test/SemaCXX/constexpr-default-arg.cpp
===================================================================
--- /dev/null
+++ test/SemaCXX/constexpr-default-arg.cpp
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -std=c++1y -fsyntax-only -verify %s
+
+// expected-no-diagnostics
+
+constexpr bool equals(const float& arg = 1.0f) {
+ return arg == 1.0f;
+}
+
+constexpr bool test_default_arg() {
+ return equals() && equals();
+}
Index: lib/AST/ExprConstant.cpp
===================================================================
--- lib/AST/ExprConstant.cpp
+++ lib/AST/ExprConstant.cpp
@@ -1162,8 +1162,15 @@
APValue &CallStackFrame::createTemporary(const void *Key,
bool IsLifetimeExtended) {
- APValue &Result = Temporaries[Key];
- assert(Result.isUninit() && "temporary created multiple times");
+ auto LB = Temporaries.lower_bound(Key);
+
+ // If an element with key Key is found, reset the value and return it. This
+ // can happen if Key is part of a default argument expression.
+ if (LB != Temporaries.end() && LB->first == Key)
+ return LB->second = APValue();
+
+ APValue &Result =
+ Temporaries.insert(LB, std::make_pair(Key, APValue()))->second;
Info.CleanupStack.push_back(Cleanup(&Result, IsLifetimeExtended));
return Result;
}
Index: test/SemaCXX/constexpr-default-arg.cpp
===================================================================
--- /dev/null
+++ test/SemaCXX/constexpr-default-arg.cpp
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -std=c++1y -fsyntax-only -verify %s
+
+// expected-no-diagnostics
+
+constexpr bool equals(const float& arg = 1.0f) {
+ return arg == 1.0f;
+}
+
+constexpr bool test_default_arg() {
+ return equals() && equals();
+}
Index: lib/AST/ExprConstant.cpp
===================================================================
--- lib/AST/ExprConstant.cpp
+++ lib/AST/ExprConstant.cpp
@@ -1162,8 +1162,15 @@
APValue &CallStackFrame::createTemporary(const void *Key,
bool IsLifetimeExtended) {
- APValue &Result = Temporaries[Key];
- assert(Result.isUninit() && "temporary created multiple times");
+ auto LB = Temporaries.lower_bound(Key);
+
+ // If an element with key Key is found, reset the value and return it. This
+ // can happen if Key is part of a default argument expression.
+ if (LB != Temporaries.end() && LB->first == Key)
+ return LB->second = APValue();
+
+ APValue &Result =
+ Temporaries.insert(LB, std::make_pair(Key, APValue()))->second;
Info.CleanupStack.push_back(Cleanup(&Result, IsLifetimeExtended));
return Result;
}
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