Subzero: fix partially initialized ManagedStatic assert
This is the same fix that I applied to LLVM7 here:
https://swiftshader-review.googlesource.com/c/SwiftShader/+/37608
but this time to subzero-llvm.
Fixes ANGLE dEQP tests run against SwiftShader/Subzero.
Bug: chromium:151653536
Change-Id: Ia4725b74d068a3afd99d407c53b11f757bc5e11f
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/42469
Presubmit-Ready: Antonio Maiorano <amaiorano@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/third_party/llvm-subzero/include/llvm/Support/Compiler.h b/third_party/llvm-subzero/include/llvm/Support/Compiler.h
index 55148a4..803fd48 100644
--- a/third_party/llvm-subzero/include/llvm/Support/Compiler.h
+++ b/third_party/llvm-subzero/include/llvm/Support/Compiler.h
@@ -243,6 +243,15 @@
#define LLVM_FALLTHROUGH
#endif
+/// LLVM_REQUIRE_CONSTANT_INITIALIZATION - Apply this to globals to ensure that
+/// they are constant initialized.
+#if __has_cpp_attribute(clang::require_constant_initialization)
+#define LLVM_REQUIRE_CONSTANT_INITIALIZATION \
+ [[clang::require_constant_initialization]]
+#else
+#define LLVM_REQUIRE_CONSTANT_INITIALIZATION
+#endif
+
/// LLVM_EXTENSION - Support compilers where we have a keyword to suppress
/// pedantic diagnostics.
#ifdef __GNUC__
diff --git a/third_party/llvm-subzero/include/llvm/Support/ManagedStatic.h b/third_party/llvm-subzero/include/llvm/Support/ManagedStatic.h
index 7ce86ee..e4ebd7c 100644
--- a/third_party/llvm-subzero/include/llvm/Support/ManagedStatic.h
+++ b/third_party/llvm-subzero/include/llvm/Support/ManagedStatic.h
@@ -36,18 +36,37 @@
static void call(void *Ptr) { delete[](T *)Ptr; }
};
+// If the current compiler is MSVC 2017 or earlier, then we have to work around
+// a bug where MSVC emits code to perform dynamic initialization even if the
+// class has a constexpr constructor. Instead, fall back to the C++98 strategy
+// where there are no constructors or member initializers. We can remove this
+// when MSVC 2019 (19.20+) is our minimum supported version.
+#if !defined(__clang__) && defined(_MSC_VER) && _MSC_VER < 1920
+#define LLVM_AVOID_CONSTEXPR_CTOR
+#endif
+
/// ManagedStaticBase - Common base class for ManagedStatic instances.
class ManagedStaticBase {
protected:
+#ifndef LLVM_AVOID_CONSTEXPR_CTOR
+ mutable std::atomic<void *> Ptr{};
+ mutable void (*DeleterFn)(void *) = nullptr;
+ mutable const ManagedStaticBase *Next = nullptr;
+#else
// This should only be used as a static variable, which guarantees that this
// will be zero initialized.
mutable std::atomic<void *> Ptr;
- mutable void (*DeleterFn)(void*);
+ mutable void (*DeleterFn)(void *);
mutable const ManagedStaticBase *Next;
+#endif
void RegisterManagedStatic(void *(*creator)(), void (*deleter)(void*)) const;
public:
+#ifndef LLVM_AVOID_CONSTEXPR_CTOR
+ constexpr ManagedStaticBase() = default;
+#endif
+
/// isConstructed - Return true if this object has not been created yet.
bool isConstructed() const { return Ptr != nullptr; }
diff --git a/third_party/llvm-subzero/lib/Support/CommandLine.cpp b/third_party/llvm-subzero/lib/Support/CommandLine.cpp
index fa1782c..3e77cd0 100644
--- a/third_party/llvm-subzero/lib/Support/CommandLine.cpp
+++ b/third_party/llvm-subzero/lib/Support/CommandLine.cpp
@@ -383,11 +383,16 @@
GlobalParser->registerCategory(this);
}
-// A special subcommand representing no subcommand
-ManagedStatic<SubCommand> llvm::cl::TopLevelSubCommand;
+// A special subcommand representing no subcommand. It is particularly important
+// that this ManagedStatic uses constant initailization and not dynamic
+// initialization because it is referenced from cl::opt constructors, which run
+// dynamically in an arbitrary order.
+LLVM_REQUIRE_CONSTANT_INITIALIZATION ManagedStatic<SubCommand>
+llvm::cl::TopLevelSubCommand;
// A special subcommand that can be used to put an option into all subcommands.
-ManagedStatic<SubCommand> llvm::cl::AllSubCommands;
+LLVM_REQUIRE_CONSTANT_INITIALIZATION ManagedStatic<SubCommand>
+llvm::cl::AllSubCommands;
void SubCommand::registerSubCommand() {
GlobalParser->registerSubCommand(this);
