[clang] e62b3a9 - Unwind-tables: move back to original logic outline for kind.

[Tim Northover via cfe-commits]

Author: Tim Northover
Date: 2022-09-29T13:39:06+01:00
New Revision: e62b3a9375d8694efe5bf3d1409bec9be0d288e9

URL: https://github.com/llvm/llvm-project/commit/e62b3a9375d8694efe5bf3d1409bec9be0d288e9
DIFF: https://github.com/llvm/llvm-project/commit/e62b3a9375d8694efe5bf3d1409bec9be0d288e9.diff

LOG: Unwind-tables: move back to original logic outline for kind.

There are lots of options interacting in complex ways here, and when moving to
`getDefaultUnwindTableLevel` I had refactored this and changed behaviour in
some cases. So this reverts the basic structure of the logic back to the
original, while leaving the hook in the new style.

Added: 
    

Modified: 
    clang/lib/Driver/ToolChains/Clang.cpp
    clang/test/Driver/clang-translation.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index c93a7276f1a9..5ea9e8085302 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5470,27 +5470,24 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   // -fasynchronous-unwind-tables and -fnon-call-exceptions interact in more
   // complicated ways.
   auto SanitizeArgs = TC.getSanitizerArgs(Args);
-  auto UnwindTables = TC.getDefaultUnwindTableLevel(Args);
-
-  const bool HasSyncUnwindTables = Args.hasFlag(
-      options::OPT_funwind_tables, options::OPT_fno_unwind_tables, false);
-  if (Args.hasFlag(options::OPT_fasynchronous_unwind_tables,
-                   options::OPT_fno_asynchronous_unwind_tables,
-                   SanitizeArgs.needsUnwindTables()) &&
-      !Freestanding)
-    UnwindTables = ToolChain::UnwindTableLevel::Asynchronous;
-  else if (HasSyncUnwindTables)
-    UnwindTables = ToolChain::UnwindTableLevel::Synchronous;
-  else if (Args.hasFlag(options::OPT_fno_unwind_tables,
-                   options::OPT_fno_asynchronous_unwind_tables,
-                   options::OPT_funwind_tables, false) || Freestanding)
-    UnwindTables = ToolChain::UnwindTableLevel::None;
-
-
-  if (UnwindTables == ToolChain::UnwindTableLevel::Synchronous)
-    CmdArgs.push_back("-funwind-tables=1");
-  else if (UnwindTables == ToolChain::UnwindTableLevel::Asynchronous)
+
+  bool IsAsyncUnwindTablesDefault =
+      TC.getDefaultUnwindTableLevel(Args) == ToolChain::UnwindTableLevel::Asynchronous;
+  bool IsSyncUnwindTablesDefault =
+      TC.getDefaultUnwindTableLevel(Args) == ToolChain::UnwindTableLevel::Synchronous;
+
+  bool AsyncUnwindTables = Args.hasFlag(
+      options::OPT_fasynchronous_unwind_tables,
+      options::OPT_fno_asynchronous_unwind_tables,
+      (IsAsyncUnwindTablesDefault || SanitizeArgs.needsUnwindTables()) &&
+          !Freestanding);
+  bool UnwindTables =
+      Args.hasFlag(options::OPT_funwind_tables, options::OPT_fno_unwind_tables,
+                   IsSyncUnwindTablesDefault && !Freestanding);
+  if (AsyncUnwindTables)
     CmdArgs.push_back("-funwind-tables=2");
+  else if (UnwindTables)
+     CmdArgs.push_back("-funwind-tables=1");
 
   // Prepare `-aux-target-cpu` and `-aux-target-feature` unless
   // `--gpu-use-aux-triple-only` is specified.
@@ -7316,7 +7313,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("-faddrsig");
 
   if ((Triple.isOSBinFormatELF() || Triple.isOSBinFormatMachO()) &&
-      (EH || UnwindTables != ToolChain::UnwindTableLevel::None ||
+      (EH || UnwindTables || AsyncUnwindTables ||
        DebugInfoKind != codegenoptions::NoDebugInfo))
     CmdArgs.push_back("-D__GCC_HAVE_DWARF2_CFI_ASM=1");
 

diff  --git a/clang/test/Driver/clang-translation.c b/clang/test/Driver/clang-translation.c
index 715b0b3150bd..ca98ca5e8228 100644
--- a/clang/test/Driver/clang-translation.c
+++ b/clang/test/Driver/clang-translation.c
@@ -99,6 +99,17 @@
 //
 // ARM64-EXPLICIT-UWTABLE-APPLE: -funwind-tables
 
+// RUN: %clang -target arm64-apple-macosx -### -ffreestanding -fasynchronous-unwind-tables %s 2>&1 | \
+// RUN: FileCheck --check-prefix=ASYNC-UNWIND-FREESTANDING %s
+//
+// ASYNC-UNWIND-FREESTANDING: -funwind-tables=2
+
+// Quite weird behaviour, but it's a long-standing default.
+// RUN: %clang -target x86_64-apple-macosx -### -fno-unwind-tables %s 2>&1 |\
+// RUN: FileCheck --check-prefix=NOUNWIND-IGNORED %s
+//
+// NOUNWIND-IGNORED: -funwind-tables=2
+
 // RUN: %clang -target arm64-apple-ios10 -fno-exceptions -### -S %s -arch arm64 2>&1 | \
 // RUN: FileCheck -check-prefix=ARM64-APPLE-EXCEP %s
 // ARM64-APPLE-EXCEP-NOT: -funwind-tables