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

[Rainer Orth via Phabricator via cfe-commits]

ro created this revision.
ro added reviewers: jyknight, venkatra, efriedma, jrtc27.
ro added a project: clang.
Herald added a subscriber: fedor.sergeev.
ro requested review of this revision.
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Even after D86621 <https://reviews.llvm.org/D86621>, `clang -m32` on Solaris/sparcv9 doesn't inline atomics with 8-byte
operands, unlike `gcc`.  This leads to many link failures in the testsuite (undefined references
to `__atomic_load_8` and `__sync_val_compare_and_swap_8`.  Until a proper codegen fix can be implemented, this patch works around the first of those by linking with `-latomic`.

Tested on `sparcv9-sun-solaris2.11`.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D118021

Files:
  clang/lib/Driver/ToolChains/CommonArgs.cpp
  clang/lib/Driver/ToolChains/CommonArgs.h
  clang/lib/Driver/ToolChains/Solaris.cpp


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 lacks atomics support on 32-bit SPARC, 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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