Enable LLVM asan support for NetBSD/amd64

[krytarowski]

Summary

Enable LLVM asan sanitizer for NetBSD/amd64.

Don't generate -ldl for dlopen(3)-like functions on NetBSD.
These features are available in libc on NetBSD.

Sponsored by <The NetBSD Foundation>

[krytarowski]

$ cat /tmp/test.cpp                                                                                                                                                                  
#include <stdio.h>

int
main(int argc, char **argv)
{
        int *array = new int[100];
        delete [] array;
        return array[argc];
}
$ /usr/pkg/bin/clang++ -fsanitize=address test.cpp -g
$ ./a.out                                             
ASAN:DEADLYSIGNAL
=================================================================
==13051==ERROR: AddressSanitizer: SEGV on unknown address 0x1c2800000008 (pc 0x00000047db6a bp 0x7f7fff366770 sp 0x7f7fff366740 T0)
==13051==The signal is caused by a READ memory access.
    #0 0x47db69 in main /tmp/test.cpp:8:9
    #1 0x4095ea in ___start (/tmp/a.out+0x4095ea)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /tmp/test.cpp:8:9 in main
==13051==ABORTING

[dim]

LGTM

lib/Driver/ToolChains/CommonArgs.cpp

void tools::linkSanitizerRuntimeDeps(const ToolChain &TC,
   // There's no libpthread or librt on RTEMS.
   if (TC.getTriple().getOS() != llvm::Triple::RTEMS) {
     CmdArgs.push_back("-lpthread");
     CmdArgs.push_back("-lrt");
   }
   CmdArgs.push_back("-lm");
   // There's no libdl on FreeBSD or RTEMS.
   if (TC.getTriple().getOS() != llvm::Triple::FreeBSD &&
+      TC.getTriple().getOS() != llvm::Triple::NetBSD &&
       TC.getTriple().getOS() != llvm::Triple::RTEMS)
     CmdArgs.push_back("-ldl");
 }
 
 static void
 collectSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
                          SmallVectorImpl<StringRef> &SharedRuntimes,
                          SmallVectorImpl<StringRef> &StaticRuntimes,

lib/Driver/ToolChains/NetBSD.h

public:
   CXXStdlibType GetDefaultCXXStdlibType() const override;
 
   std::string findLibCxxIncludePath() const override;
   void addLibStdCxxIncludePaths(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
 
   bool IsUnwindTablesDefault() const override { return true; }
+  SanitizerMask getSupportedSanitizers() const override;
 
 protected:
   Tool *buildAssembler() const override;
   Tool *buildLinker() const override;
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_NETBSD_H

lib/Driver/ToolChains/NetBSD.cpp

 #include "NetBSD.h"
 #include "Arch/ARM.h"
 #include "Arch/Mips.h"
 #include "Arch/Sparc.h"
 #include "CommonArgs.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/Options.h"
+#include "clang/Driver/SanitizerArgs.h"
 #include "llvm/Option/ArgList.h"
 
 using namespace clang::driver;
 using namespace clang::driver::tools;
 using namespace clang::driver::toolchains;
 using namespace clang;
 using namespace llvm::opt;
 
void netbsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
   Args.AddAllArgs(CmdArgs, options::OPT_e);
   Args.AddAllArgs(CmdArgs, options::OPT_s);
   Args.AddAllArgs(CmdArgs, options::OPT_t);
   Args.AddAllArgs(CmdArgs, options::OPT_Z_Flag);
   Args.AddAllArgs(CmdArgs, options::OPT_r);
 
+  bool NeedsSanitizerDeps = addSanitizerRuntimes(getToolChain(), Args, CmdArgs);
   AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
 
   unsigned Major, Minor, Micro;
   getToolChain().getTriple().getOSVersion(Major, Minor, Micro);
   bool useLibgcc = true;
   if (Major >= 7 || Major == 0) {
     switch (getToolChain().getArch()) {
     case llvm::Triple::aarch64:
void netbsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   }
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
     addOpenMPRuntime(CmdArgs, getToolChain(), Args);
     if (D.CCCIsCXX()) {
       getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
       CmdArgs.push_back("-lm");
     }
+    if (NeedsSanitizerDeps)
+      linkSanitizerRuntimeDeps(getToolChain(), CmdArgs);
     if (Args.hasArg(options::OPT_pthread))
       CmdArgs.push_back("-lpthread");
     CmdArgs.push_back("-lc");
 
     if (useLibgcc) {
       if (Args.hasArg(options::OPT_static)) {
         // libgcc_eh depends on libc, so resolve as much as possible,
         // pull in any new requirements from libc and then get the rest
std::string NetBSD::findLibCxxIncludePath() const {
   return getDriver().SysRoot + "/usr/include/c++/";
 }
 
 void NetBSD::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
                                       llvm::opt::ArgStringList &CC1Args) const {
   addLibStdCXXIncludePaths(getDriver().SysRoot, "/usr/include/g++", "", "", "",
                            "", DriverArgs, CC1Args);
 }
+
+SanitizerMask NetBSD::getSupportedSanitizers() const {
+  const bool IsX86_64 = getTriple().getArch() == llvm::Triple::x86_64;
+  SanitizerMask Res = ToolChain::getSupportedSanitizers();
+  if (IsX86_64) {
+    Res |= SanitizerKind::Address;
+  }
+  return Res;
+}