Split DWARF: Allow -gmlt/-gsplit-dwarf to override rather than complement each other

It doesn't make any sense to enable -gmlt with -gsplit-dwarf, since
-gmlt is designed for on-line symbolication (and -gsplit-dwarf normally
emits all the -gmlt data into the .o anyway - so there's nothing to
split out except redundant/duplicate info).

With this change they override each other, -gmlt -gsplit-dwarf is the
same as -gsplit-dwarf and -gsplit-dwarf -gmlt is the same as -gmlt.

llvm-svn: 243694

diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 8bbc92d..ce39b87 100644 (file)
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -3644,9 +3644,11 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   // Use the last option from "-g" group. "-gline-tables-only" and "-gdwarf-x"
   // are preserved, all other debug options are substituted with "-g".
   Args.ClaimAllArgs(options::OPT_g_Group);
+  Arg *SplitDwarfArg = Args.getLastArg(options::OPT_gsplit_dwarf);
   if (Arg *A = Args.getLastArg(options::OPT_g_Group)) {
-    if (A->getOption().matches(options::OPT_gline_tables_only) ||
-        A->getOption().matches(options::OPT_g1)) {
+    if ((A->getOption().matches(options::OPT_gline_tables_only) ||
+         A->getOption().matches(options::OPT_g1)) &&
+        (!SplitDwarfArg || A->getIndex() > SplitDwarfArg->getIndex())) {
       // FIXME: we should support specifying dwarf version with
       // -gline-tables-only.
       CmdArgs.push_back("-gline-tables-only");
@@ -3656,6 +3658,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
           Triple.getOS() == llvm::Triple::FreeBSD ||
           Triple.getOS() == llvm::Triple::Solaris)
         CmdArgs.push_back("-gdwarf-2");
+      SplitDwarfArg = nullptr;
     } else if (A->getOption().matches(options::OPT_gdwarf_2))
       CmdArgs.push_back("-gdwarf-2");
     else if (A->getOption().matches(options::OPT_gdwarf_3))
@@ -3685,8 +3688,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   // -gsplit-dwarf should turn on -g and enable the backend dwarf
   // splitting and extraction.
   // FIXME: Currently only works on Linux.
-  if (getToolChain().getTriple().isOSLinux() &&
-      Args.hasArg(options::OPT_gsplit_dwarf)) {
+  if (getToolChain().getTriple().isOSLinux() && SplitDwarfArg) {
     CmdArgs.push_back("-g");
     CmdArgs.push_back("-backend-option");
     CmdArgs.push_back("-split-dwarf=Enable");
@@ -4970,8 +4972,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
 
   // Add the split debug info name to the command lines here so we
   // can propagate it to the backend.
-  bool SplitDwarf = Args.hasArg(options::OPT_gsplit_dwarf) &&
-                    getToolChain().getTriple().isOSLinux() &&
+  bool SplitDwarf = SplitDwarfArg && getToolChain().getTriple().isOSLinux() &&
                     (isa<AssembleJobAction>(JA) || isa<CompileJobAction>(JA) ||
                      isa<BackendJobAction>(JA));
   const char *SplitDwarfOut;

diff --git a/clang/test/Driver/split-debug.c b/clang/test/Driver/split-debug.c
index 6296c46..ae79067 100644 (file)
--- a/clang/test/Driver/split-debug.c
+++ b/clang/test/Driver/split-debug.c
@@ -32,3 +32,20 @@
 // RUN: FileCheck -check-prefix=CHECK-IAS < %t %s
 //
 // CHECK-IAS: objcopy
+
+// RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -gmlt -S -### %s 2> %t
+// RUN: FileCheck -check-prefix=CHECK-GMLT-OVER-SPLIT < %t %s
+//
+// CHECK-GMLT-OVER-SPLIT: "-gline-tables-only"
+// CHECK-GMLT-OVER-SPLIT-NOT: "-g"
+// CHECK-GMLT-OVER-SPLIT-NOT: "-split-dwarf=Enable"
+// CHECK-GMLT-OVER-SPLIT-NOT: "-split-dwarf-file"
+
+// RUN: %clang -target x86_64-unknown-linux-gnu -gmlt -gsplit-dwarf -S -### %s 2> %t
+// RUN: FileCheck -check-prefix=CHECK-SPLIT-OVER-GMLT < %t %s
+//
+// CHECK-SPLIT-OVER-GMLT-NOT: "-gline-tables-only"
+// CHECK-SPLIT-OVER-GMLT: "-g"
+// CHECK-SPLIT-OVER-GMLT: "-split-dwarf=Enable"
+// CHECK-SPLIT-OVER-GMLT: "-split-dwarf-file"
+// CHECK-SPLIT-OVER-GMLT-NOT: "-gline-tables-only"