[clang][LTO] Setting Desired Default AIX Debugging Options

[qiongsiwu1]

Summary

On AIX, strict-dwarf defaults to true. This patch implement this default behaviour. Additionally, it adds debug tuning tests.

[shchenz]

clang/lib/Driver/ToolChains/CommonArgs.cpp

589

Typo: presense -> absence?

590

Could you also post another patch to fix the no-lto path to remove the redundant -debugger-tuning=dbx on AIX? We should make the lto mode and non-lto mode be consistent.

clang/test/Driver/lto-aix.c

8

Can we add case that by default, no -debugger-tune is emitted?

[qiongsiwu1]

This comment was removed by qiongsiwu1.

[qiongsiwu1]

Address code review.

[qiongsiwu1]

clang/lib/Driver/ToolChains/CommonArgs.cpp

589

Thanks for the catch! I realized the original code was confusing (probably incorrect). The logic is rewritten and the comment is eliminated.

590

Yes will do!

[qiongsiwu1]

Clean up test cases.

[shchenz]

LGTM. Thanks.

clang/lib/Driver/ToolChains/CommonArgs.cpp

588

nit: maybe we don't need to change this. OPT_gTune_Group will check the four debugger types.

[qiongsiwu1]

Address a review comment.

clang/lib/Driver/ToolChains/CommonArgs.cpp

if (A->getOption().matches(options::OPT_glldb))
       CmdArgs.push_back(
           Args.MakeArgString(Twine(PluginOptPrefix) + "-debugger-tune=lldb"));
     else if (A->getOption().matches(options::OPT_gsce))
       CmdArgs.push_back(
           Args.MakeArgString(Twine(PluginOptPrefix) + "-debugger-tune=sce"));
     else if (A->getOption().matches(options::OPT_gdbx))
       CmdArgs.push_back(
           Args.MakeArgString(Twine(PluginOptPrefix) + "-debugger-tune=dbx"));
-    else
+    else {
+      // On platforms other than AIX, gdb is the default option.
+      // On AIX, dbx will be automatically pick up in the presense of the
+      // debugger tuning argument, so set gdb only if it is specified.
+      if (!IsOSAIX || A->getOption().matches(options::OPT_ggdb) ||
+          Args.getLastArg(options::OPT_ggdbN_Group))
         CmdArgs.push_back(
             Args.MakeArgString(Twine(PluginOptPrefix) + "-debugger-tune=gdb"));
     }
+  }
+
+  if (IsOSAIX) {
+    // On AIX, strict-dwarf is assumed to be true if any debug option is
+    // specified, unless clang is told explicitly not to assume so.
+    Arg *A = Args.getLastArg(options::OPT_g_Group);
+    bool EnableDebugInfo = A && !A->getOption().matches(options::OPT_g0) &&
+                           !A->getOption().matches(options::OPT_ggdb0);
+    if (EnableDebugInfo && Args.hasFlag(options::OPT_gstrict_dwarf,
+                                        options::OPT_gno_strict_dwarf, true))
+      CmdArgs.push_back(
+          Args.MakeArgString(Twine(PluginOptPrefix) + "-strict-dwarf=true"));
+  }
 
   bool UseSeparateSections =
       isUseSeparateSections(ToolChain.getEffectiveTriple());
 
   if (Args.hasFlag(options::OPT_ffunction_sections,
                    options::OPT_fno_function_sections, UseSeparateSections))
     CmdArgs.push_back(
         Args.MakeArgString(Twine(PluginOptPrefix) + "-function-sections=1"));

clang/test/Driver/lto-aix.c

 // Test LTO path, mcpu and opt level options
 // RUN: %clang --target=powerpc-ibm-aix -### %s -flto -fuse-ld=ld -O3 2>&1 \
 // RUN:   | FileCheck -check-prefixes=LTOPATH,MCPUOPTLEVEL %s
 //
 // LTOPATH: "-bplugin:{{.*}}libLTO.{{so|dll|dylib}}"
 // MCPUOPTLEVEL: "-bplugin_opt:-mcpu={{.*}}" "-bplugin_opt:-O3"
+//
+// Test debugging options
+// RUN: %clang -target powerpc-ibm-aix-xcoff -### %s -flto -g 2>&1 \
+// RUN:   | FileCheck -check-prefix=STRICT %s
+// RUN: %clang -target powerpc64-ibm-aix-xcoff -### %s -flto -g 2>&1 \
+// RUN:   | FileCheck -check-prefix=STRICT %s
+// RUN: %clang -target powerpc-ibm-aix-xcoff -### %s -flto -g -gdbx 2>&1 \
+// RUN:   | FileCheck -check-prefix=DBX -check-prefix=STRICT %s
+// RUN: %clang -target powerpc-ibm-aix-xcoff -### %s -flto -g -ggdb 2>&1 \
+// RUN:   | FileCheck -check-prefix=GDB -check-prefix=STRICT %s
+// RUN: %clang -target powerpc-ibm-aix-xcoff -### %s -flto -g -ggdb0 2>&1 \
+// RUN:   | FileCheck -check-prefix=GDB -check-prefix=NOSTRICT %s
+// RUN: %clang -target powerpc-ibm-aix-xcoff -### %s -flto -g -ggdb1 2>&1 \
+// RUN:   | FileCheck -check-prefix=GDB -check-prefix=STRICT %s
+// RUN: %clang -target powerpc-ibm-aix-xcoff -### %s -flto -g -g0 2>&1 \
+// RUN:   | FileCheck -check-prefix=NOSTRICT %s
+// RUN: %clang -target powerpc-ibm-aix-xcoff -### %s -flto -g -gno-strict-dwarf 2>&1 \
+// RUN:   | FileCheck -check-prefix=NOSTRICT %s
+// RUN: %clang -target powerpc-ibm-aix-xcoff -### %s -flto -gstrict-dwarf 2>&1 \
+// RUN:   | FileCheck -check-prefix=NOSTRICT %s
+//
+// DBX:    "-bplugin_opt:-debugger-tune=dbx"
+// GDB:    "-bplugin_opt:-debugger-tune=gdb"
+// STRICT:       "-bplugin_opt:-strict-dwarf=true"
+// NOSTRICT-NOT: "-bplugin_opt:-strict-dwarf=true"