DebugInfo: Add the ability to disable DWARF name tables entirely

This changes the current default behavior (from emitting pubnames by
default, to not emitting them by default) & moves to matching GCC's
behavior* with one significant difference: -gno(-gnu)-pubnames disables
pubnames even in the presence of -gsplit-dwarf (though -gsplit-dwarf
still by default enables -ggnu-pubnames). This allows users to disable
pubnames (& the new DWARF5 accelerated access tables) when they might
not be worth the size overhead.

* GCC's behavior is that -ggnu-pubnames and -gpubnames override each
other, and that -gno-gnu-pubnames and -gno-pubnames act as synonyms and
disable either kind of pubnames if they come last. (eg: -gpubnames
-gno-gnu-pubnames causes no pubnames (neither gnu or standard) to be
emitted)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@340206 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Driver/CC1Options.td

@@ -197,10 +197,6 @@ def dwarf_column_info : Flag<["-"], "dwarf-column-info">,
   HelpText<"Turn on column location information.">;
 def split_dwarf : Flag<["-"], "split-dwarf">,
   HelpText<"Split out the dwarf .dwo sections">;
-def gnu_pubnames : Flag<["-"], "gnu-pubnames">,
-  HelpText<"Emit newer GNU style pubnames">;
-def arange_sections : Flag<["-"], "arange_sections">,
-  HelpText<"Emit DWARF .debug_arange sections">;
 def dwarf_ext_refs : Flag<["-"], "dwarf-ext-refs">,
   HelpText<"Generate debug info with external references to clang modules"
            " or precompiled headers">;

include/clang/Driver/Options.td

@@ -1807,6 +1807,8 @@ def gno_column_info : Flag<["-"], "gno-column-info">, Group<g_flags_Group>, Flag
 def gsplit_dwarf : Flag<["-"], "gsplit-dwarf">, Group<g_flags_Group>;
 def ggnu_pubnames : Flag<["-"], "ggnu-pubnames">, Group<g_flags_Group>, Flags<[CC1Option]>;
 def gno_gnu_pubnames : Flag<["-"], "gno-gnu-pubnames">, Group<g_flags_Group>, Flags<[CC1Option]>;
+def gpubnames : Flag<["-"], "gpubnames">, Group<g_flags_Group>, Flags<[CC1Option]>;
+def gno_pubnames : Flag<["-"], "gno-pubnames">, Group<g_flags_Group>, Flags<[CC1Option]>;
 def gdwarf_aranges : Flag<["-"], "gdwarf-aranges">, Group<g_flags_Group>;
 def gmodules : Flag <["-"], "gmodules">, Group<gN_Group>,
   HelpText<"Generate debug info with external references to clang modules"

include/clang/Frontend/CodeGenOptions.def

@@ -326,7 +326,7 @@ CODEGENOPT(DebugInfoForProfiling, 1, 0)
 CODEGENOPT(PreserveVec3Type, 1, 0)
 
 /// Whether to emit .debug_gnu_pubnames section instead of .debug_pubnames.
-CODEGENOPT(GnuPubnames, 1, 0)
+CODEGENOPT(DebugNameTable, 2, 0)
 
 CODEGENOPT(NoPLT, 1, 0)
 

lib/CodeGen/CGDebugInfo.cpp

@@ -581,9 +581,8 @@ void CGDebugInfo::CreateCompileUnit() {
       0 /* DWOid */, CGOpts.SplitDwarfInlining, CGOpts.DebugInfoForProfiling,
       CGM.getTarget().getTriple().isNVPTX()
           ? llvm::DICompileUnit::DebugNameTableKind::None
-          : CGOpts.GnuPubnames
-                ? llvm::DICompileUnit::DebugNameTableKind::GNU
-                : llvm::DICompileUnit::DebugNameTableKind::Default);
+          : static_cast<llvm::DICompileUnit::DebugNameTableKind>(
+                CGOpts.DebugNameTable));
 }
 
 llvm::DIType *CGDebugInfo::CreateType(const BuiltinType *BT) {

lib/Driver/ToolChains/Clang.cpp

@@ -3060,11 +3060,18 @@ static void RenderDebugOptions(const ToolChain &TC, const Driver &D,
       CmdArgs.push_back("-debug-info-macro");
 
   // -ggnu-pubnames turns on gnu style pubnames in the backend.
-  if (Args.hasFlag(options::OPT_ggnu_pubnames, options::OPT_gno_gnu_pubnames,
-                   false))
-    if (checkDebugInfoOption(Args.getLastArg(options::OPT_ggnu_pubnames), Args,
-                             D, TC))
-      CmdArgs.push_back("-ggnu-pubnames");
+  const auto *PubnamesArg =
+      Args.getLastArg(options::OPT_ggnu_pubnames, options::OPT_gno_gnu_pubnames,
+                      options::OPT_gpubnames, options::OPT_gno_pubnames);
+  if (SplitDWARFArg ||
+      (PubnamesArg && checkDebugInfoOption(PubnamesArg, Args, D, TC)))
+    if (!PubnamesArg ||
+        (!PubnamesArg->getOption().matches(options::OPT_gno_gnu_pubnames) &&
+         !PubnamesArg->getOption().matches(options::OPT_gno_pubnames)))
+      CmdArgs.push_back(PubnamesArg && PubnamesArg->getOption().matches(
+                                           options::OPT_gpubnames)
+                            ? "-gpubnames"
+                            : "-ggnu-pubnames");
 
   // -gdwarf-aranges turns on the emission of the aranges section in the
   // backend.

lib/Frontend/CompilerInvocation.cpp

@@ -55,6 +55,7 @@
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/Linker/Linker.h"
 #include "llvm/MC/MCTargetOptions.h"
 #include "llvm/Option/Arg.h"
@@ -643,7 +644,12 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.SampleProfileFile = Args.getLastArgValue(OPT_fprofile_sample_use_EQ);
   Opts.DebugInfoForProfiling = Args.hasFlag(
       OPT_fdebug_info_for_profiling, OPT_fno_debug_info_for_profiling, false);
-  Opts.GnuPubnames = Args.hasArg(OPT_ggnu_pubnames);
+  Opts.DebugNameTable = static_cast<unsigned>(
+      Args.hasArg(OPT_ggnu_pubnames)
+          ? llvm::DICompileUnit::DebugNameTableKind::GNU
+          : Args.hasArg(OPT_gpubnames)
+                ? llvm::DICompileUnit::DebugNameTableKind::Default
+                : llvm::DICompileUnit::DebugNameTableKind::None);
 
   setPGOInstrumentor(Opts, Args, Diags);
   Opts.InstrProfileOutput =

test/CodeGen/debug-info-global-constant.c

@@ -7,7 +7,7 @@
 // CHECK: @i = internal constant i32 1, align 4, !dbg ![[I:[0-9]+]]
 // CHECK: ![[I]] = !DIGlobalVariableExpression(var: ![[VAR:.*]], expr: !DIExpression(DW_OP_constu, 1, DW_OP_stack_value))
 // CHECK: ![[VAR]] = distinct !DIGlobalVariable(name: "i",
-// CHECK: !DICompileUnit({{.*}}globals: ![[GLOBALS:[0-9]+]])
+// CHECK: !DICompileUnit({{.*}}globals: ![[GLOBALS:[0-9]+]]
 // CHECK: ![[GLOBALS]] = !{![[I]]}
 static const int i = 1;
 

test/CodeGen/debug-info-macro.c

@@ -23,7 +23,7 @@
 // NO_MACRO-NOT: DIMacro
 // NO_MACRO-NOT: DIMacroFile
 
-// CHECK:  !DICompileUnit({{.*}} macros: [[Macros:![0-9]+]])
+// CHECK:  !DICompileUnit({{.*}} macros: [[Macros:![0-9]+]]
 // CHECK:  [[EmptyMD:![0-9]+]] = !{}
 
 // NO_PCH: [[Macros]] = !{[[MainMacroFile:![0-9]+]], [[BuiltinMacro:![0-9]+]], {{.*}}, [[DefineC1:![0-9]+]], [[DefineA:![0-9]+]], [[UndefC1:![0-9]+]]}

test/CodeGen/debug-info-names.c

@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited %s -o - | FileCheck %s
+// RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited %s -o - -gpubnames | FileCheck --check-prefix=DEFAULT %s
+// RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited %s -o - -ggnu-pubnames | FileCheck --check-prefix=GNU %s
+
+// CHECK: !DICompileUnit({{.*}}, nameTableKind: None
+// DEFAULT-NOT: !DICompileUnit({{.*}}, nameTableKind:
+// GNU: !DICompileUnit({{.*}}, nameTableKind: GNU
+
+void f1() {
+}

test/Driver/debug-options.c

@@ -133,9 +133,18 @@
 // RUN: %clang -### -c -gstrict-dwarf -gno-strict-dwarf %s 2>&1 \
 // RUN:        | FileCheck -check-prefix=GIGNORE %s
 //
-// RUN: %clang -### -c -ggnu-pubnames %s 2>&1 | FileCheck -check-prefix=GOPT %s
-// RUN: %clang -### -c %s 2>&1 | FileCheck -check-prefix=NOGOPT %s
-// RUN: %clang -### -c -ggnu-pubnames -gno-gnu-pubnames %s 2>&1 | FileCheck -check-prefix=NOGOPT %s
+// RUN: %clang -### -c -ggnu-pubnames %s 2>&1 | FileCheck -check-prefix=GPUB %s
+// RUN: %clang -### -c %s 2>&1 | FileCheck -check-prefix=NOPUB %s
+// RUN: %clang -### -c -ggnu-pubnames -gno-gnu-pubnames %s 2>&1 | FileCheck -check-prefix=NOPUB %s
+// RUN: %clang -### -c -ggnu-pubnames -gno-pubnames %s 2>&1 | FileCheck -check-prefix=NOPUB %s
+//
+// RUN: %clang -### -c -gpubnames %s 2>&1 | FileCheck -check-prefix=PUB %s
+// RUN: %clang -### -c %s 2>&1 | FileCheck -check-prefix=NOPUB %s
+// RUN: %clang -### -c -gpubnames -gno-gnu-pubnames %s 2>&1 | FileCheck -check-prefix=NOPUB %s
+// RUN: %clang -### -c -gpubnames -gno-pubnames %s 2>&1 | FileCheck -check-prefix=NOPUB %s
+//
+// RUN: %clang -### -c -gsplit-dwarf %s 2>&1 | FileCheck -check-prefix=GPUB %s
+// RUN: %clang -### -c -gsplit-dwarf -gno-pubnames %s 2>&1 | FileCheck -check-prefix=NOPUB %s
 //
 // RUN: %clang -### -c -gdwarf-aranges %s 2>&1 | FileCheck -check-prefix=GARANGE %s
 //
@@ -229,8 +238,11 @@
 //
 // GIGNORE-NOT: "argument unused during compilation"
 //
-// GOPT: -ggnu-pubnames
-// NOGOPT-NOT: -ggnu-pubnames
+// GPUB: -ggnu-pubnames
+// NOPUB-NOT: -ggnu-pubnames
+// NOPUB-NOT: -gpubnames
+//
+// PUB: -gpubnames
 //
 // GARANGE: -generate-arange-section
 //