[MinGW] Allow using ASan

Linking to ASan for MinGW is similar to MSVC, but MinGW always links
the MSVCRT dynamically, so there is only one of the MSVC cases to
consider.

When linking to a shared compiler runtime library on MinGW, the suffix
of the import library is .dll.a.

The existing case of .dll as suffix for windows in general doesn't
seem correct (since this is used for linking). As long as callers never
actually set the Shared flag, the default static suffix of .lib also
worked fine for import libraries as well.

Differential Revision: https://reviews.llvm.org/D52538

4 files changed, 42 insertions, 4 deletions

diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 8933e905fce..f05c8a39823 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -367,8 +367,10 @@ std::string ToolChain::getCompilerRT(const ArgList &Args, StringRef Component,
       TT.isWindowsMSVCEnvironment() || TT.isWindowsItaniumEnvironment();
 
   const char *Prefix = IsITANMSVCWindows ? "" : "lib";
-  const char *Suffix = Shared ? (Triple.isOSWindows() ? ".dll" : ".so")
+  const char *Suffix = Shared ? (Triple.isOSWindows() ? ".lib" : ".so")
                               : (IsITANMSVCWindows ? ".lib" : ".a");
+  if (Shared && Triple.isWindowsGNUEnvironment())
+    Suffix = ".dll.a";
 
   for (const auto &LibPath : getLibraryPaths()) {
     SmallString<128> P(LibPath);
diff --git a/clang/lib/Driver/ToolChains/MinGW.cpp b/clang/lib/Driver/ToolChains/MinGW.cpp
index a88e00f0c8e..f9e641e63ff 100644
--- a/clang/lib/Driver/ToolChains/MinGW.cpp
+++ b/clang/lib/Driver/ToolChains/MinGW.cpp
@@ -14,6 +14,7 @@
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
+#include "clang/Driver/SanitizerArgs.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
@@ -95,7 +96,7 @@ void tools::MinGW::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                         const char *LinkingOutput) const {
   const ToolChain &TC = getToolChain();
   const Driver &D = TC.getDriver();
-  // const SanitizerArgs &Sanitize = TC.getSanitizerArgs();
+  const SanitizerArgs &Sanitize = TC.getSanitizerArgs();
 
   ArgStringList CmdArgs;
 
@@ -187,8 +188,6 @@ void tools::MinGW::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   TC.AddFilePathLibArgs(Args, CmdArgs);
   AddLinkerInputs(TC, Inputs, Args, CmdArgs, JA);
 
-  // TODO: Add ASan stuff here
-
   // TODO: Add profile stuff here
 
   if (TC.ShouldLinkCXXStdlib(Args)) {
@@ -231,6 +230,24 @@ void tools::MinGW::Linker::ConstructJob(Compilation &C, const JobAction &JA,
       if (Args.hasArg(options::OPT_pthread))
         CmdArgs.push_back("-lpthread");
 
+      if (Sanitize.needsAsanRt()) {
+        // MinGW always links against a shared MSVCRT.
+        CmdArgs.push_back(
+            TC.getCompilerRTArgString(Args, "asan_dynamic", true));
+        CmdArgs.push_back(
+            TC.getCompilerRTArgString(Args, "asan_dynamic_runtime_thunk"));
+        CmdArgs.push_back(Args.MakeArgString("--require-defined"));
+        CmdArgs.push_back(Args.MakeArgString(TC.getArch() == llvm::Triple::x86
+                                                 ? "___asan_seh_interceptor"
+                                                 : "__asan_seh_interceptor"));
+        // Make sure the linker consider all object files from the dynamic
+        // runtime thunk.
+        CmdArgs.push_back(Args.MakeArgString("--whole-archive"));
+        CmdArgs.push_back(Args.MakeArgString(
+            TC.getCompilerRT(Args, "asan_dynamic_runtime_thunk")));
+        CmdArgs.push_back(Args.MakeArgString("--no-whole-archive"));
+      }
+
       if (!HasWindowsApp) {
         // Add system libraries. If linking to libwindowsapp.a, that import
         // library replaces all these and we shouldn't accidentally try to
@@ -407,6 +424,12 @@ toolchains::MinGW::GetExceptionModel(const ArgList &Args) const {
   return llvm::ExceptionHandling::DwarfCFI;
 }
 
+SanitizerMask toolchains::MinGW::getSupportedSanitizers() const {
+  SanitizerMask Res = ToolChain::getSupportedSanitizers();
+  Res |= SanitizerKind::Address;
+  return Res;
+}
+
 void toolchains::MinGW::AddCudaIncludeArgs(const ArgList &DriverArgs,
                                            ArgStringList &CC1Args) const {
   CudaInstallation.AddCudaIncludeArgs(DriverArgs, CC1Args);
diff --git a/clang/lib/Driver/ToolChains/MinGW.h b/clang/lib/Driver/ToolChains/MinGW.h
index 0c3919d29f7..450044d4512 100644
--- a/clang/lib/Driver/ToolChains/MinGW.h
+++ b/clang/lib/Driver/ToolChains/MinGW.h
@@ -65,6 +65,8 @@ public:
   bool isPIEDefault() const override;
   bool isPICDefaultForced() const override;
 
+  SanitizerMask getSupportedSanitizers() const override;
+
   llvm::ExceptionHandling GetExceptionModel(
       const llvm::opt::ArgList &Args) const override;
 
diff --git a/clang/test/Driver/mingw-sanitizers.c b/clang/test/Driver/mingw-sanitizers.c
new file mode 100644
index 00000000000..09f28fea8ab
--- /dev/null
+++ b/clang/test/Driver/mingw-sanitizers.c
@@ -0,0 +1,11 @@
+// RUN: %clang -target i686-windows-gnu %s -### -fsanitize=address 2>&1 | FileCheck --check-prefix=ASAN-I686 %s
+// ASAN-I686: "{{.*}}libclang_rt.asan_dynamic-i386.dll.a"
+// ASAN-I686: "{{[^"]*}}libclang_rt.asan_dynamic_runtime_thunk-i386.a"
+// ASAN-I686: "--require-defined" "___asan_seh_interceptor"
+// ASAN-I686: "--whole-archive" "{{.*}}libclang_rt.asan_dynamic_runtime_thunk-i386.a" "--no-whole-archive"
+
+// RUN: %clang -target x86_64-windows-gnu %s -### -fsanitize=address 2>&1 | FileCheck --check-prefix=ASAN-X86_64 %s
+// ASAN-X86_64: "{{.*}}libclang_rt.asan_dynamic-x86_64.dll.a"
+// ASAN-X86_64: "{{[^"]*}}libclang_rt.asan_dynamic_runtime_thunk-x86_64.a"
+// ASAN-X86_64: "--require-defined" "__asan_seh_interceptor"
+// ASAN-X86_64: "--whole-archive" "{{.*}}libclang_rt.asan_dynamic_runtime_thunk-x86_64.a" "--no-whole-archive"