[Driver] Fix search paths on x32

[jrtc27]

Summary

When targeting x32, the x32 libraries and headers should be used, not
the x86_64 ones (which may not even be available), so prioritise those
and use the right multiarch triple.

[glaubitz]

As a heads-up, powerpcspe needs a similar treatment as it suffers from the same problem:

cd build-llvm \
CFLAGS=`dpkg-buildflags --get CFLAGS`; \
CFLAGS="$CFLAGS `dpkg-buildflags --get CPPFLAGS`"; \
echo $CFLAGS; \
bin/clang++ -c $CFLAGS -std=c++11 ../lib/Fuzzer/*.cpp -IFuzzer; \
ar ruv libFuzzer.a Fuzzer*.o
-g -O2 -fdebug-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2
In file included from ../lib/Fuzzer/FuzzerCrossOver.cpp:12:
In file included from ../lib/Fuzzer/FuzzerDefs.h:15:
In file included from /usr/lib/gcc/powerpc-linux-gnuspe/7.3.0/../../../../include/c++/7.3.0/cassert:43:
In file included from /usr/lib/gcc/powerpc-linux-gnuspe/7.3.0/../../../../include/powerpc-linux-gnuspe/c++/7.3.0/bits/c++config.h:533:
In file included from /usr/lib/gcc/powerpc-linux-gnuspe/7.3.0/../../../../include/powerpc-linux-gnuspe/c++/7.3.0/bits/os_defines.h:39:
/usr/include/features.h:419:12: fatal error: 'sys/cdefs.h' file not found
#  include <sys/cdefs.h>
           ^~~~~~~~~~~~~
1 error generated.
ar: `u' modifier ignored since `D' is the default (see `U')
ar: creating libFuzzer.a
ar: Fuzzer*.o: No such file or directory

Full build log in: https://people.debian.org/~glaubitz/llvm-toolchain-4.0_4.0.1-10.log.gz

Like x32, powerpcspe is just a variant on an existing architecture, namely powerpc but with a different ABI and hence a suffix in the GNU triplet name (full triplet name is "powerpc-linux-gnuspe").

[jrtc27]

Ping?

[dschuff]

This should probably have some tests. It looks like there are some existing x32 tests in test/Driver/linux-header-search.cpp and test/Driver/cross-linux.c that might be relevant for updating.

[sylvestre.ledru]

@jrtc27 are you going to take care of the tests? Thanks

[glaubitz]

I have just rebased the patch and I am looking at the tests now.

[glaubitz]

I don't think that "test/Driver/linux-header-search.cpp" needs to be updated. x32 is actually supported in both an x86_64-linux-gnu environment and x86_64-linux-gnux32 environment. In order to update test/Driver/linux-header-search.cpp, we would have to add a debian-10-x32 chroot to the LLVM test environment. However, the patch by @jrtc27 actually doesn't break the previous tests as his patch just allows the native header and library paths as altnernative search paths.

The same applies to test/Driver/cross-linux.c. The x32 test there will still remain valid, even with the changes.

[glaubitz]

I have pushed a rebase revision here: https://reviews.llvm.org/D52050

I have no idea how to edit the author though.

[jrtc27]

Superseded by D52050

lib/Driver/ToolChains/Gnu.cpp

/*static*/ void Generic_GCC::GCCInstallationDetector::CollectLibDirsAndTriples(
   static const char *const X86_64LibDirs[] = {"/lib64", "/lib"};
   static const char *const X86_64Triples[] = {
       "x86_64-linux-gnu",       "x86_64-unknown-linux-gnu",
       "x86_64-pc-linux-gnu",    "x86_64-redhat-linux6E",
       "x86_64-redhat-linux",    "x86_64-suse-linux",
       "x86_64-manbo-linux-gnu", "x86_64-linux-gnu",
       "x86_64-slackware-linux", "x86_64-linux-android",
       "x86_64-unknown-linux"};
-  static const char *const X32LibDirs[] = {"/libx32"};
+  static const char *const X32LibDirs[] = {"/libx32", "/lib"};
+  static const char *const X32Triples[] = {
+      "x86_64-linux-gnux32",    "x86_64-unknown-linux-gnux32",
+      "x86_64-pc-linux-gnux32"};
   static const char *const X86LibDirs[] = {"/lib32", "/lib"};
   static const char *const X86Triples[] = {
       "i686-linux-gnu",       "i686-pc-linux-gnu",     "i486-linux-gnu",
       "i386-linux-gnu",       "i386-redhat-linux6E",   "i686-redhat-linux",
       "i586-redhat-linux",    "i386-redhat-linux",     "i586-suse-linux",
       "i486-slackware-linux", "i686-montavista-linux", "i686-linux-android",
       "i586-linux-gnu"};
 
case llvm::Triple::thumbeb:
     LibDirs.append(begin(ARMebLibDirs), end(ARMebLibDirs));
     if (TargetTriple.getEnvironment() == llvm::Triple::GNUEABIHF) {
       TripleAliases.append(begin(ARMebHFTriples), end(ARMebHFTriples));
     } else {
       TripleAliases.append(begin(ARMebTriples), end(ARMebTriples));
     }
     break;
   case llvm::Triple::x86_64:
-    LibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
-    TripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
     // x32 is always available when x86_64 is available, so adding it as
     // secondary arch with x86_64 triples
     if (TargetTriple.getEnvironment() == llvm::Triple::GNUX32) {
-      BiarchLibDirs.append(begin(X32LibDirs), end(X32LibDirs));
+      LibDirs.append(begin(X32LibDirs), end(X32LibDirs));
+      TripleAliases.append(begin(X32Triples), end(X32Triples));
+      BiarchLibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
       BiarchTripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
     } else {
+      LibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
+      TripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
       BiarchLibDirs.append(begin(X86LibDirs), end(X86LibDirs));
       BiarchTripleAliases.append(begin(X86Triples), end(X86Triples));
     }
     break;
   case llvm::Triple::x86:
     LibDirs.append(begin(X86LibDirs), end(X86LibDirs));
     // MCU toolchain is 32 bit only and its triple alias is TargetTriple
     // itself, which will be appended below.

lib/Driver/ToolChains/Linux.cpp

if (TargetEnvironment == llvm::Triple::GNUEABIHF) {
         return "armeb-linux-gnueabi";
     }
     break;
   case llvm::Triple::x86:
     if (D.getVFS().exists(SysRoot + "/lib/i386-linux-gnu"))
       return "i386-linux-gnu";
     break;
   case llvm::Triple::x86_64:
-    // We don't want this for x32, otherwise it will match x86_64 libs
-    if (TargetEnvironment != llvm::Triple::GNUX32 &&
-        D.getVFS().exists(SysRoot + "/lib/x86_64-linux-gnu"))
+    if (TargetEnvironment == llvm::Triple::GNUX32) {
+      if (D.getVFS().exists(SysRoot + "/lib/x86_64-linux-gnux32"))
+        return "x86_64-linux-gnux32";
+    } else {
+      if (D.getVFS().exists(SysRoot + "/lib/x86_64-linux-gnu"))
         return "x86_64-linux-gnu";
+    }
     break;
   case llvm::Triple::aarch64:
     if (D.getVFS().exists(SysRoot + "/lib/aarch64-linux-gnu"))
       return "aarch64-linux-gnu";
     break;
   case llvm::Triple::aarch64_be:
     if (D.getVFS().exists(SysRoot + "/lib/aarch64_be-linux-gnu"))
       return "aarch64_be-linux-gnu";
void Linux::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
   // Implement generic Debian multiarch support.
   const StringRef X86_64MultiarchIncludeDirs[] = {
       "/usr/include/x86_64-linux-gnu",
 
       // FIXME: These are older forms of multiarch. It's not clear that they're
       // in use in any released version of Debian, so we should consider
       // removing them.
       "/usr/include/i686-linux-gnu/64", "/usr/include/i486-linux-gnu/64"};
+  const StringRef X32MultiarchIncludeDirs[] = {
+      "/usr/include/x86_64-linux-gnux32"};
   const StringRef X86MultiarchIncludeDirs[] = {
       "/usr/include/i386-linux-gnu",
 
       // FIXME: These are older forms of multiarch. It's not clear that they're
       // in use in any released version of Debian, so we should consider
       // removing them.
       "/usr/include/x86_64-linux-gnu/32", "/usr/include/i686-linux-gnu",
       "/usr/include/i486-linux-gnu"};
const StringRef SparcMultiarchIncludeDirs[] = {
       "/usr/include/sparc-linux-gnu"};
   const StringRef Sparc64MultiarchIncludeDirs[] = {
       "/usr/include/sparc64-linux-gnu"};
   const StringRef SYSTEMZMultiarchIncludeDirs[] = {
       "/usr/include/s390x-linux-gnu"};
   ArrayRef<StringRef> MultiarchIncludeDirs;
   switch (getTriple().getArch()) {
   case llvm::Triple::x86_64:
+    if (getTriple().getEnvironment() == llvm::Triple::GNUX32)
+      MultiarchIncludeDirs = X32MultiarchIncludeDirs;
+    else
       MultiarchIncludeDirs = X86_64MultiarchIncludeDirs;
     break;
   case llvm::Triple::x86:
     MultiarchIncludeDirs = X86MultiarchIncludeDirs;
     break;
   case llvm::Triple::aarch64:
   case llvm::Triple::aarch64_be:
     MultiarchIncludeDirs = AArch64MultiarchIncludeDirs;
     break;