The Darwin kernel does not provide useful guard variable support.
Issue this as an IR-gen error; it's not really worthwhile doing this
"right", i.e. in Sema, because IR gen knows a lot of tricks beyond
what the constant evaluator knows.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@127854 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Driver/CC1Options.td b/include/clang/Driver/CC1Options.td
index c0fb23d..e103b5b 100644
--- a/include/clang/Driver/CC1Options.td
+++ b/include/clang/Driver/CC1Options.td
@@ -110,6 +110,8 @@
HelpText<"Do not emit code that uses the red zone.">;
def dwarf_debug_flags : Separate<"-dwarf-debug-flags">,
HelpText<"The string to embed in the Dwarf debug flags record.">;
+def fforbid_guard_variables : Flag<"-fforbid-guard-variables">,
+ HelpText<"Emit an error if a C++ static local initializer would need a guard variable">;
def g : Flag<"-g">, HelpText<"Generate source level debug information">;
def fcatch_undefined_behavior : Flag<"-fcatch-undefined-behavior">,
HelpText<"Generate runtime checks for undefined behavior.">;
diff --git a/include/clang/Frontend/CodeGenOptions.h b/include/clang/Frontend/CodeGenOptions.h
index ee85b65..875fbcd 100644
--- a/include/clang/Frontend/CodeGenOptions.h
+++ b/include/clang/Frontend/CodeGenOptions.h
@@ -51,6 +51,8 @@
/// Decl* various IR entities came from. Only
/// useful when running CodeGen as a
/// subroutine.
+ unsigned ForbidGuardVariables : 1; /// Issue errors if C++ guard variables
+ /// are required
unsigned FunctionSections : 1; /// Set when -ffunction-sections is enabled
unsigned HiddenWeakTemplateVTables : 1; /// Emit weak vtables and RTTI for
/// template classes with hidden visibility
@@ -128,6 +130,7 @@
DisableLLVMOpts = 0;
DisableRedZone = 0;
EmitDeclMetadata = 0;
+ ForbidGuardVariables = 0;
FunctionSections = 0;
HiddenWeakTemplateVTables = 0;
HiddenWeakVTables = 0;
diff --git a/lib/CodeGen/CGDeclCXX.cpp b/lib/CodeGen/CGDeclCXX.cpp
index 6635af8..ed25b6d 100644
--- a/lib/CodeGen/CGDeclCXX.cpp
+++ b/lib/CodeGen/CGDeclCXX.cpp
@@ -149,6 +149,14 @@
void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
llvm::GlobalVariable *DeclPtr) {
+ // If we've been asked to forbid guard variables, emit an error now.
+ // This diagnostic is hard-coded for Darwin's use case; we can find
+ // better phrasing if someone else needs it.
+ if (CGM.getCodeGenOpts().ForbidGuardVariables)
+ CGM.Error(D.getLocation(),
+ "this initialization requires a guard variable, which "
+ "the kernel does not support");
+
CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr);
}
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 6181470..11e8587 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -154,6 +154,11 @@
return getContext().Target.getTriple().getOS() == llvm::Triple::Darwin;
}
+void CodeGenModule::Error(SourceLocation loc, llvm::StringRef error) {
+ unsigned diagID = getDiags().getCustomDiagID(Diagnostic::Error, error);
+ getDiags().Report(Context.getFullLoc(loc), diagID);
+}
+
/// ErrorUnsupported - Print out an error that codegen doesn't support the
/// specified stmt yet.
void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type,
diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index 0205797..5b8164f 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -527,6 +527,9 @@
llvm::Constant *EmitAnnotateAttr(llvm::GlobalValue *GV,
const AnnotateAttr *AA, unsigned LineNo);
+ /// Error - Emit a general error that something can't be done.
+ void Error(SourceLocation loc, llvm::StringRef error);
+
/// ErrorUnsupported - Print out an error that codegen doesn't support the
/// specified stmt yet.
/// \param OmitOnError - If true, then this error should only be emitted if no
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 45fdd8b..ee4976e 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1138,6 +1138,12 @@
if (getToolChain().getTriple().getOS() != llvm::Triple::Darwin)
CmdArgs.push_back("-mconstructor-aliases");
+ // Darwin's kernel doesn't support guard variables; just die if we
+ // try to use them.
+ if (KernelOrKext &&
+ getToolChain().getTriple().getOS() == llvm::Triple::Darwin)
+ CmdArgs.push_back("-fforbid-guard-variables");
+
if (Args.hasArg(options::OPT_mms_bitfields)) {
CmdArgs.push_back("-mms-bitfields");
}
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 859eb74..31fcee2 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -127,6 +127,8 @@
Res.push_back("-fno-merge-all-constants");
if (Opts.NoCommon)
Res.push_back("-fno-common");
+ if (Opts.ForbidGuardVariables)
+ Res.push_back("-fforbid-guard-variables");
if (Opts.NoImplicitFloat)
Res.push_back("-no-implicit-float");
if (Opts.OmitLeafFramePointer)
@@ -896,6 +898,7 @@
Opts.LimitDebugInfo = Args.hasArg(OPT_flimit_debug_info);
Opts.DisableLLVMOpts = Args.hasArg(OPT_disable_llvm_optzns);
Opts.DisableRedZone = Args.hasArg(OPT_disable_red_zone);
+ Opts.ForbidGuardVariables = Args.hasArg(OPT_fforbid_guard_variables);
Opts.RelaxedAliasing = Args.hasArg(OPT_relaxed_aliasing);
Opts.DwarfDebugFlags = Args.getLastArgValue(OPT_dwarf_debug_flags);
Opts.MergeAllConstants = !Args.hasArg(OPT_fno_merge_all_constants);
diff --git a/test/CodeGenCXX/apple-kext-guard-variable.cpp b/test/CodeGenCXX/apple-kext-guard-variable.cpp
new file mode 100644
index 0000000..f9d4460
--- /dev/null
+++ b/test/CodeGenCXX/apple-kext-guard-variable.cpp
@@ -0,0 +1,9 @@
+// RUN: %clang -mtriple=x86_64-apple-darwin10 -S -mkernel -Xclang -verify %s
+
+// rdar://problem/9143356
+
+int foo();
+void test() {
+ static int y = 0;
+ static int x = foo(); // expected-error {{this initialization requires a guard variable, which the kernel does not support}}
+}