[PATCH] D118021: [Driver] Use libatomic for 32-bit SPARC atomics support

[Rainer Orth via Phabricator via cfe-commits]

ro updated this revision to Diff 403604.
ro added a comment.
Herald added a project: Sanitizers.
Herald added a subscriber: Sanitizers.

- Clarify comment.
- Use `__ATOMIC_SEQ_CST`.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D118021/new/

https://reviews.llvm.org/D118021

Files:
  clang/lib/Driver/ToolChains/CommonArgs.cpp
  clang/lib/Driver/ToolChains/CommonArgs.h
  clang/lib/Driver/ToolChains/Solaris.cpp
  compiler-rt/lib/sanitizer_common/sanitizer_atomic_clang.h


Index: compiler-rt/lib/sanitizer_common/sanitizer_atomic_clang.h
===================================================================
--- compiler-rt/lib/sanitizer_common/sanitizer_atomic_clang.h
+++ compiler-rt/lib/sanitizer_common/sanitizer_atomic_clang.h
@@ -74,13 +74,8 @@
 inline bool atomic_compare_exchange_strong(volatile T *a, typename T::Type *cmp,
                                            typename T::Type xchg,
                                            memory_order mo) {
-  typedef typename T::Type Type;
-  Type cmpv = *cmp;
-  Type prev;
-  prev = __sync_val_compare_and_swap(&a->val_dont_use, cmpv, xchg);
-  if (prev == cmpv) return true;
-  *cmp = prev;
-  return false;
+  return __atomic_compare_exchange(&a->val_dont_use, cmp, &xchg, false, mo,
+                                   __ATOMIC_SEQ_CST);
 }
 
 template<typename T>
Index: clang/lib/Driver/ToolChains/Solaris.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Solaris.cpp
+++ clang/lib/Driver/ToolChains/Solaris.cpp
@@ -132,6 +132,13 @@
       CmdArgs.push_back("-lssp_nonshared");
       CmdArgs.push_back("-lssp");
     }
+    // LLVM support for atomics on 32-bit SPARC V8+ is incomplete, so
+    // forcibly link with libatomic as a workaround.
+    if (getToolChain().getTriple().getArch() == llvm::Triple::sparc) {
+      CmdArgs.push_back(getAsNeededOption(getToolChain(), true));
+      CmdArgs.push_back("-latomic");
+      CmdArgs.push_back(getAsNeededOption(getToolChain(), false));
+    }
     CmdArgs.push_back("-lgcc_s");
     CmdArgs.push_back("-lc");
     if (!Args.hasArg(options::OPT_shared)) {
Index: clang/lib/Driver/ToolChains/CommonArgs.h
===================================================================
--- clang/lib/Driver/ToolChains/CommonArgs.h
+++ clang/lib/Driver/ToolChains/CommonArgs.h
@@ -114,6 +114,8 @@
                       bool ForceStaticHostRuntime = false,
                       bool IsOffloadingHost = false, bool GompNeedsRT = false);
 
+const char *getAsNeededOption(const ToolChain &TC, bool as_needed);
+
 llvm::opt::Arg *getLastProfileUseArg(const llvm::opt::ArgList &Args);
 llvm::opt::Arg *getLastProfileSampleUseArg(const llvm::opt::ArgList &Args);
 
Index: clang/lib/Driver/ToolChains/CommonArgs.cpp
===================================================================
--- clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -737,7 +737,7 @@
   return false;
 }
 
-static const char *getAsNeededOption(const ToolChain &TC, bool as_needed) {
+const char *tools::getAsNeededOption(const ToolChain &TC, bool as_needed) {
   assert(!TC.getTriple().isOSAIX() &&
          "AIX linker does not support any form of --as-needed option yet.");
 


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