Turn off lldb debug tuning by default for FreeBSD

[dim]

Summary

In rL242338, debugger tuning was introduced, and the tuning for FreeBSD
was set to lldb by default. However, for the foreseeable future we
still need to default to gdb tuning, since lldb is not ready for all of
FreeBSD's architectures, and some system tools (like objcopy, etc) have
not yet been adapted to cope with the lldb tuned format, which has
.apple sections.

Therefore, let FreeBSD use gdb by default for now.

[emaste]

I advocated for the lldb tuning by default on FreeBSD originally, but I didn't fully understand the implications. It turns out we're just not ready yet. So, LGTM.

[probinson]

LGTM. Somebody had actually asked for the default to be LLDB, originally, but I'm not invested which way the default goes.

[emaste]

Somebody had actually asked for the default to be LLDB, originally

That was me. I didn't quite understand what was going to change though and subsequently realized there's more work we'll need to do in gdb, and other build tools before we can set this default on FreeBSD.

lib/CodeGen/AsmPrinter/DwarfDebug.cpp

DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
   CurFn = nullptr;
   CurMI = nullptr;
   Triple TT(Asm->getTargetTriple());
 
   // Make sure we know our "debugger tuning."  The target option takes
   // precedence; fall back to triple-based defaults.
   if (Asm->TM.Options.DebuggerTuning != DebuggerKind::Default)
     DebuggerTuning = Asm->TM.Options.DebuggerTuning;
-  else if (IsDarwin || TT.isOSFreeBSD())
+  else if (IsDarwin)
     DebuggerTuning = DebuggerKind::LLDB;
   else if (TT.isPS4CPU())
     DebuggerTuning = DebuggerKind::SCE;
   else
     DebuggerTuning = DebuggerKind::GDB;
 
   // Turn on accelerator tables for LLDB by default.
   if (DwarfAccelTables == Default)

test/DebugInfo/X86/debugger-tune.ll

 ; Verify target-based defaults for "debugger tuning," and the ability to
 ; override defaults.
 ; We use existence of the debug_pubnames section to distinguish the GDB case,
 ; and the apple_names section to distinguish the LLDB case. SCE has neither.
 
 ; Verify defaults for various targets.
 ; RUN: llc -mtriple=x86_64-scei-ps4 -filetype=obj < %s | llvm-readobj -sections - | FileCheck --check-prefix=SCE %s
 ; RUN: llc -mtriple=x86_64-apple-darwin12 -filetype=obj < %s | llvm-readobj -sections - | FileCheck --check-prefix=LLDB %s
-; RUN: llc -mtriple=x86_64-pc-freebsd -filetype=obj < %s | llvm-readobj -sections - | FileCheck --check-prefix=LLDB %s
+; RUN: llc -mtriple=x86_64-pc-freebsd -filetype=obj < %s | llvm-readobj -sections - | FileCheck --check-prefix=GDB %s
 ; RUN: llc -mtriple=x86_64-pc-linux -filetype=obj < %s | llvm-readobj -sections - | FileCheck --check-prefix=GDB %s
 
 ; We can override defaults.
 ; RUN: llc -mtriple=x86_64-scei-ps4 -filetype=obj -debugger-tune=gdb < %s | llvm-readobj -sections - | FileCheck --check-prefix=GDB %s
 ; RUN: llc -mtriple=x86_64-pc-linux -filetype=obj -debugger-tune=lldb < %s | llvm-readobj -sections - | FileCheck --check-prefix=LLDB %s
 ; RUN: llc -mtriple=x86_64-apple-darwin12 -filetype=obj -debugger-tune=sce < %s | llvm-readobj -sections - | FileCheck --check-prefix=SCE %s
 
 

test/DebugInfo/X86/tls.ll

 ; RUN: llc %s -o - -filetype=asm -O0 -mtriple=x86_64-unknown-linux-gnu \
 ; RUN:   | FileCheck --check-prefix=NOEMU --check-prefix=SINGLE --check-prefix=SINGLE-64 --check-prefix=GNUOP %s
 
 ; RUN: llc %s -o - -filetype=asm -O0 -mtriple=i386-linux-gnu \
 ; RUN:   | FileCheck --check-prefix=NOEMU --check-prefix=SINGLE --check-prefix=SINGLE-32 --check-prefix=GNUOP %s
 
 ; RUN: llc %s -o - -filetype=asm -O0 -mtriple=x86_64-unknown-linux-gnu -split-dwarf=Enable \
 ; RUN:   | FileCheck --check-prefix=NOEMU --check-prefix=FISSION --check-prefix=GNUOP %s
 
 ; RUN: llc %s -o - -filetype=asm -O0 -mtriple=x86_64-scei-ps4 \
 ; RUN:   | FileCheck --check-prefix=NOEMU --check-prefix=SINGLE --check-prefix=SINGLE-64 --check-prefix=STDOP %s
 
 ; RUN: llc %s -o - -filetype=asm -O0 -mtriple=x86_64-apple-darwin \
 ; RUN:   | FileCheck --check-prefix=NOEMU --check-prefix=DARWIN --check-prefix=STDOP %s
 
 ; RUN: llc %s -o - -filetype=asm -O0 -mtriple=x86_64-unknown-freebsd \
-; RUN:   | FileCheck --check-prefix=NOEMU --check-prefix=SINGLE --check-prefix=SINGLE-64 --check-prefix=STDOP %s
+; RUN:   | FileCheck --check-prefix=NOEMU --check-prefix=SINGLE --check-prefix=SINGLE-64 --check-prefix=GNUOP %s
 
 ; RUN: llc %s -o - -filetype=asm -O0 -mtriple=x86_64-unknown-linux-gnu -emulated-tls \
 ; RUN:   | FileCheck --check-prefix=SINGLE --check-prefix=EMUSINGLE-64 \
 ; RUN:     --check-prefix=EMUGNUOP --check-prefix=EMU %s
 
 ; RUN: llc %s -o - -filetype=asm -O0 -mtriple=i386-linux-gnu -emulated-tls \
 ; RUN:   | FileCheck --check-prefix=SINGLE --check-prefix=EMUSINGLE-32 \
 ; RUN:     --check-prefix=EMUGNUOP --check-prefix=EMU %s