[Clang FE, SystemZ] Recognize -mrecord-mcount CL option.

Recognize -mrecord-mcount from the command line and add a function attribute
"mrecord-mcount" when passed.

Only valid on SystemZ (when used with -mfentry).

Review: Ulrich Weigand
https://reviews.llvm.org/D71627

clang/include/clang/Basic/CodeGenOptions.def

@@ -113,6 +113,7 @@ VALUE_CODEGENOPT(XRayInstructionThreshold , 32, 200)
 CODEGENOPT(InstrumentForProfiling , 1, 0) ///< Set when -pg is enabled.
 CODEGENOPT(CallFEntry , 1, 0) ///< Set when -mfentry is enabled.
 CODEGENOPT(MNopMCount , 1, 0) ///< Set when -mnop-mcount is enabled.
+CODEGENOPT(RecordMCount , 1, 0) ///< Set when -mrecord-mcount is enabled.
 CODEGENOPT(PackedStack , 1, 0) ///< Set when -mpacked-stack is enabled.
 CODEGENOPT(LessPreciseFPMAD  , 1, 0) ///< Enable less precise MAD instructions to
                                      ///< be generated.

clang/include/clang/Driver/Options.td

@@ -2477,6 +2477,8 @@ def mfentry : Flag<["-"], "mfentry">, HelpText<"Insert calls to fentry at functi
   Flags<[CC1Option]>, Group<m_Group>;
 def mnop_mcount : Flag<["-"], "mnop-mcount">, HelpText<"Generate mcount/__fentry__ calls as nops. To activate they need to be patched in.">,
   Flags<[CC1Option]>, Group<m_Group>;
+def mrecord_mcount : Flag<["-"], "mrecord-mcount">, HelpText<"Generate a __mcount_loc section entry for each __fentry__ call.">,
+  Flags<[CC1Option]>, Group<m_Group>;
 def mpacked_stack : Flag<["-"], "mpacked-stack">, HelpText<"Use packed stack layout (SystemZ only).">,
   Flags<[CC1Option]>, Group<m_Group>;
 def mips16 : Flag<["-"], "mips16">, Group<m_mips_Features_Group>;

clang/lib/CodeGen/CodeGenFunction.cpp

@@ -968,6 +968,17 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
             << "-mnop-mcount" << "-mfentry";
         Fn->addFnAttr("mnop-mcount");
       }
+
+      if (CGM.getCodeGenOpts().RecordMCount) {
+        if (getContext().getTargetInfo().getTriple().getArch() !=
+            llvm::Triple::systemz)
+          CGM.getDiags().Report(diag::err_opt_not_valid_on_target)
+            << "-mrecord-mcount";
+        if (!CGM.getCodeGenOpts().CallFEntry)
+          CGM.getDiags().Report(diag::err_opt_not_valid_without_opt)
+            << "-mrecord-mcount" << "-mfentry";
+        Fn->addFnAttr("mrecord-mcount");
+      }
     }
   }
 

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4990,6 +4990,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   if (TC.SupportsProfiling())
     Args.AddLastArg(CmdArgs, options::OPT_mnop_mcount);
 
+  if (TC.SupportsProfiling())
+    Args.AddLastArg(CmdArgs, options::OPT_mrecord_mcount);
+
   Args.AddLastArg(CmdArgs, options::OPT_mpacked_stack);
 
   if (Args.getLastArg(options::OPT_fapple_kext) ||

clang/lib/Frontend/CompilerInvocation.cpp

@@ -1104,6 +1104,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.InstrumentForProfiling = Args.hasArg(OPT_pg);
   Opts.CallFEntry = Args.hasArg(OPT_mfentry);
   Opts.MNopMCount = Args.hasArg(OPT_mnop_mcount);
+  Opts.RecordMCount = Args.hasArg(OPT_mrecord_mcount);
   Opts.PackedStack = Args.hasArg(OPT_mpacked_stack);
   Opts.EmitOpenCLArgMetadata = Args.hasArg(OPT_cl_kernel_arg_info);
 

clang/test/CodeGen/mrecord-mcount.c

@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -pg -mfentry -mrecord-mcount -triple s390x-ibm-linux -emit-llvm \
+// RUN:   -o - %s 2>&1 | FileCheck  %s
+// RUN: not %clang_cc1 -pg -mrecord-mcount -triple s390x-ibm-linux -emit-llvm -o - \
+// RUN:   %s 2>&1 | FileCheck -check-prefix=NOMFENTRY %s
+// RUN: %clang_cc1 -mfentry -mrecord-mcount -triple s390x-ibm-linux -emit-llvm -o - \
+// RUN:   %s 2>&1 | FileCheck -check-prefix=NOPG %s
+// RUN: %clang_cc1 -mrecord-mcount -triple s390x-ibm-linux -emit-llvm -o - %s \
+// RUN:   2>&1 | FileCheck -check-prefix=NOPG %s
+// RUN: not %clang_cc1 -pg -mfentry -mrecord-mcount -triple x86_64-linux-gnu \
+// RUN:   -emit-llvm -o - %s 2>&1 | FileCheck -check-prefix=X86 %s
+
+int foo(void) {
+  return 0;
+}
+
+int __attribute__((no_instrument_function)) no_instrument(void) {
+  return foo();
+}
+
+//CHECK: attributes #0 = { {{.*}}"mrecord-mcount"{{.*}} }
+//CHECK: attributes #1 = { {{.*}} }
+//CHECK-NOT: attributes #1 = { {{.*}}"mrecord-mcount"{{.*}} }
+//NOMFENTRY: error: option '-mrecord-mcount' cannot be specified without '-mfentry'
+//NOPG-NOT: attributes #0 = { {{.*}}"mrecord-mcount"{{.*}} }
+//NOPG-NOT: attributes #1 = { {{.*}}"mrecord-mcount"{{.*}} }
+//X86: error: option '-mrecord-mcount' cannot be specified on this target