[Driver] Link shared asan runtime lib with -z now on Solaris/x86

As detailed in Issue llvm#64126, several asan tests `FAIL` due to a cycle in
`AsanInitInternal`.  This can by avoided by disabling lazy binding with `ld
-z now`.

Tested on `amd64-pc-solaris2.11` and `x86_64-pc-linux-gnu`.

Differential Revision: https://reviews.llvm.org/D156325

Author: rorth

clang/lib/Driver/ToolChains/Solaris.cpp

@@ -151,18 +151,22 @@ void solaris::Linker::ConstructJob(Compilation &C, const JobAction &JA,
       CmdArgs.push_back("-lgcc");
       CmdArgs.push_back("-lm");
     }
+    const SanitizerArgs &SA = getToolChain().getSanitizerArgs(Args);
     if (NeedsSanitizerDeps) {
       linkSanitizerRuntimeDeps(getToolChain(), CmdArgs);
 
       // Work around Solaris/amd64 ld bug when calling __tls_get_addr directly.
       // However, ld -z relax=transtls is available since Solaris 11.2, but not
       // in Illumos.
-      const SanitizerArgs &SA = getToolChain().getSanitizerArgs(Args);
       if (getToolChain().getTriple().getArch() == llvm::Triple::x86_64 &&
           (SA.needsAsanRt() || SA.needsStatsRt() ||
            (SA.needsUbsanRt() && !SA.requiresMinimalRuntime())))
         CmdArgs.push_back("-zrelax=transtls");
     }
+    // Avoid AsanInitInternal cycle, Issue #64126.
+    if (getToolChain().getTriple().isX86() && SA.needsSharedRt() &&
+        SA.needsAsanRt())
+      CmdArgs.push_back("-znow");
   }
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles,

clang/test/Driver/solaris-ld-sanitizer.c

@@ -49,3 +49,19 @@
 // RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-X64-UBSAN %s
 // CHECK-LD-X64-UBSAN: -zrelax=transtls
+
+/// General tests that the ld -z now workaround is only applied on
+/// Solaris/i386 with shared libclang_rt.asan.. Note that we use sysroot to
+/// make these tests independent of the host system.
+
+/// Check i386-pc-solaris2.11, 32bit, shared libclang_rt.asan
+// RUN: %clang -fsanitize=address -shared-libasan --target=i386-pc-solaris2.11 %s -### 2>&1 \
+// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD-X32-ASAN-SHARED %s
+// CHECK-LD-X32-ASAN-SHARED: -znow
+
+/// Check i386-pc-solaris2.11, 32bit, static libclang_rt.asan
+// RUN: %clang -fsanitize=address --target=i386-pc-solaris2.11 %s -### 2>&1 \
+// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD-X32-ASAN %s
+// CHECK-LD-X32-ASAN-NOT: -znow