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zero9178 requested review of this revision.
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When using the -fno-rtti option of the GCC style clang++, using typeid results
in an error. The MSVC STL however kindly provides a define flag called
_HAS_STATIC_RTTI, which either enables or disables uses of typeid throughout
the STL. By default, if undefined, it is set to 1, enabling the use of typeid.
With this patch, _HAS_STATIC_RTTI is set to 0 when -fno-rtti is specified. This
way various headers of the MSVC STL like functional can be consumed without
compilation failures.
----
Some context: I was first made aware of this define in this bug report
regarding twoPhase lookup:
https://bugs.chromium.org/p/chromium/issues/detail?id=996675
Back then however there was still a usage of typeid left unguarded, which has
since been fixed in this commit https://github.com/microsoft/STL/issues/340.
Since that is November 2019, so a rather recent version of MSVC, this will not
work in versions prior to this fix.
For compat one could maybe allow `typeid(void)`, but that is beyond the scope
of this patch either way I think.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D103771
Files:
clang/lib/Driver/ToolChains/MSVC.cpp
clang/lib/Driver/ToolChains/MSVC.h
clang/test/Driver/msvc-static-rtti.cpp
Index: clang/test/Driver/msvc-static-rtti.cpp
===================================================================
--- /dev/null
+++ clang/test/Driver/msvc-static-rtti.cpp
@@ -0,0 +1,5 @@
+// RUN: %clang -target x86_64-pc-windows-msvc -fno-rtti -### %s 2>&1 |
FileCheck %s -check-prefix STATIC-RTTI-DEF
+// RUN: %clang -target x86_64-pc-windows-msvc -frtti -### %s 2>&1 | FileCheck
%s -check-prefix STATIC-RTTI-DEF-NOT
+
+// STATIC-RTTI-DEF: -D_HAS_STATIC_RTTI=0
+// STATIC-RTTI-DEF-NOT: -D_HAS_STATIC_RTTI=0
Index: clang/lib/Driver/ToolChains/MSVC.h
===================================================================
--- clang/lib/Driver/ToolChains/MSVC.h
+++ clang/lib/Driver/ToolChains/MSVC.h
@@ -122,6 +122,11 @@
bool FoundMSVCInstall() const { return !VCToolChainPath.empty(); }
+ void
+ addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
+ llvm::opt::ArgStringList &CC1Args,
+ Action::OffloadKind DeviceOffloadKind) const override;
+
protected:
void AddSystemIncludeWithSubfolder(const llvm::opt::ArgList &DriverArgs,
llvm::opt::ArgStringList &CC1Args,
Index: clang/lib/Driver/ToolChains/MSVC.cpp
===================================================================
--- clang/lib/Driver/ToolChains/MSVC.cpp
+++ clang/lib/Driver/ToolChains/MSVC.cpp
@@ -1555,3 +1555,11 @@
return DAL;
}
+
+void MSVCToolChain::addClangTargetOptions(
+ const ArgList &DriverArgs, ArgStringList &CC1Args,
+ Action::OffloadKind DeviceOffloadKind) const {
+ if (DriverArgs.hasArg(options::OPT_fno_rtti, options::OPT_frtti,
+ /*Default=*/false))
+ CC1Args.push_back("-D_HAS_STATIC_RTTI=0");
+}
Index: clang/test/Driver/msvc-static-rtti.cpp
===================================================================
--- /dev/null
+++ clang/test/Driver/msvc-static-rtti.cpp
@@ -0,0 +1,5 @@
+// RUN: %clang -target x86_64-pc-windows-msvc -fno-rtti -### %s 2>&1 | FileCheck %s -check-prefix STATIC-RTTI-DEF
+// RUN: %clang -target x86_64-pc-windows-msvc -frtti -### %s 2>&1 | FileCheck %s -check-prefix STATIC-RTTI-DEF-NOT
+
+// STATIC-RTTI-DEF: -D_HAS_STATIC_RTTI=0
+// STATIC-RTTI-DEF-NOT: -D_HAS_STATIC_RTTI=0
Index: clang/lib/Driver/ToolChains/MSVC.h
===================================================================
--- clang/lib/Driver/ToolChains/MSVC.h
+++ clang/lib/Driver/ToolChains/MSVC.h
@@ -122,6 +122,11 @@
bool FoundMSVCInstall() const { return !VCToolChainPath.empty(); }
+ void
+ addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
+ llvm::opt::ArgStringList &CC1Args,
+ Action::OffloadKind DeviceOffloadKind) const override;
+
protected:
void AddSystemIncludeWithSubfolder(const llvm::opt::ArgList &DriverArgs,
llvm::opt::ArgStringList &CC1Args,
Index: clang/lib/Driver/ToolChains/MSVC.cpp
===================================================================
--- clang/lib/Driver/ToolChains/MSVC.cpp
+++ clang/lib/Driver/ToolChains/MSVC.cpp
@@ -1555,3 +1555,11 @@
return DAL;
}
+
+void MSVCToolChain::addClangTargetOptions(
+ const ArgList &DriverArgs, ArgStringList &CC1Args,
+ Action::OffloadKind DeviceOffloadKind) const {
+ if (DriverArgs.hasArg(options::OPT_fno_rtti, options::OPT_frtti,
+ /*Default=*/false))
+ CC1Args.push_back("-D_HAS_STATIC_RTTI=0");
+}
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