[Driver] Add flag enabling the function stack size section that was added in r319430

[seaneveson]

Summary

Adds the -fstack-size-section flag to enable the .stack_sizes section. The flag defaults to on for the PS4 triple.

Follow up change from: https://reviews.llvm.org/D39788

Original RFC: http://lists.llvm.org/pipermail/llvm-dev/2017-August/117028.html

[seaneveson]

Ping.

[MatzeB]

Looks good to me, but I'm not too familiar with the clang driver code. So it would be good if you could at least add some more experienced clang developers into the reviewer list and wait some more days before committing.

I also wonder whether it would be possible to move the fact that it defaults to on for PS4 into the PS4CPU.cpp file somehow (not that things are distributed that cleanly right now anyway).

[probinson]

The title says "Add cc1 option..." which to me implies a "cc1 only" option. What you're actually doing is adding a driver option. Please update the title.

test/Driver/stack-size-section.c

3

Driver tests use -### to report the command line they'd use to invoke cc1, and verify the presence or absence of the option that you expect to see in the cc1 command line. The actual functionality test (presence or absence of something in the IR or whatever) should go in some other more appropriate place.
Also, we use FileCheck not grep.

[seaneveson]

Improve tests.

[seaneveson]

In D40712#949979, @MatzeB wrote:

I also wonder whether it would be possible to move the fact that it defaults to on for PS4 into the PS4CPU.cpp file somehow (not that things are distributed that cleanly right now anyway).

I see what you're saying, but I can't see an easy way to do that right now, and there are already a number of target dependent defaults done in the same way.

[seaneveson]

Ping.

[bruno]

lib/Driver/ToolChains/Clang.cpp

3783

What happens when you invoke cc1 directly for ps4 and don't specify any of the two options? Is it going to default to not using stack size section? It also seems that all non ps4 targets will get -fno-stack-size-section flag by default in cc1, is it really needed?

[seaneveson]

Thanks Bruno,

Changed the default for cc1 to be false regardless of the target. The default in the driver is still true for PS4 (only).

[bruno]

Thanks! LGTM

include/clang/Driver/Options.td

def ffunction_sections : Flag<["-"], "ffunction-sections">, Group<f_Group>,
   Flags<[CC1Option]>,
   HelpText<"Place each function in its own section (ELF Only)">;
 def fno_function_sections : Flag<["-"], "fno-function-sections">,
   Group<f_Group>, Flags<[CC1Option]>;
 def fdata_sections : Flag <["-"], "fdata-sections">, Group<f_Group>,
  Flags<[CC1Option]>, HelpText<"Place each data in its own section (ELF Only)">;
 def fno_data_sections : Flag <["-"], "fno-data-sections">, Group<f_Group>,
   Flags<[CC1Option]>;
+def fstack_size_section : Flag<["-"], "fstack-size-section">, Group<f_Group>, Flags<[CC1Option]>,
+  HelpText<"Emit section containing metadata on function stack sizes">;
+def fno_stack_size_section : Flag<["-"], "fno-stack-size-section">, Group<f_Group>, Flags<[CC1Option]>,
+  HelpText<"Don't emit section containing metadata on function stack sizes">;
 
 def funique_section_names : Flag <["-"], "funique-section-names">,
   Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Use unique names for text and data sections (ELF Only)">;
 def fno_unique_section_names : Flag <["-"], "fno-unique-section-names">,
   Group<f_Group>, Flags<[CC1Option]>;
 
 def fstrict_return : Flag<["-"], "fstrict-return">, Group<f_Group>,

include/clang/Frontend/CodeGenOptions.def

CODEGENOPT(InstrumentFunctions , 1, 0) ///< Set when -finstrument-functions is
                                        ///< enabled.
 CODEGENOPT(InstrumentFunctionsAfterInlining , 1, 0) ///< Set when
                           ///< -finstrument-functions-after-inlining is enabled.
 CODEGENOPT(InstrumentFunctionEntryBare , 1, 0) ///< Set when
                                ///< -finstrument-function-entry-bare is enabled.
 
 CODEGENOPT(XRayInstrumentFunctions , 1, 0) ///< Set when -fxray-instrument is
                                            ///< enabled.
+CODEGENOPT(StackSizeSection  , 1, 0) ///< Set when -fstack-size-section is enabled.
 
 ///< Set when -fxray-always-emit-customevents is enabled.
 CODEGENOPT(XRayAlwaysEmitCustomEvents , 1, 0)
 
 ///< Set the minimum number of instructions in a function to determine selective
 ///< XRay instrumentation.
 VALUE_CODEGENOPT(XRayInstructionThreshold , 32, 200)
 

lib/CodeGen/BackendUtil.cpp

static void initTargetOptions(llvm::TargetOptions &Options,
   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
   Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
   Options.FunctionSections = CodeGenOpts.FunctionSections;
   Options.DataSections = CodeGenOpts.DataSections;
   Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
+  Options.EmitStackSizeSection = CodeGenOpts.StackSizeSection;
 
   if (CodeGenOpts.EnableSplitDwarf)
     Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
   Options.MCOptions.MCIncrementalLinkerCompatible =

lib/Driver/ToolChains/Clang.cpp

if (Arg *A = Args.getLastArg(options::OPT_fconstant_string_class_EQ)) {
     CmdArgs.push_back(A->getValue());
   }
 
   if (Arg *A = Args.getLastArg(options::OPT_ftabstop_EQ)) {
     CmdArgs.push_back("-ftabstop");
     CmdArgs.push_back(A->getValue());
   }
 
+  if (Args.hasFlag(options::OPT_fstack_size_section,
+                   options::OPT_fno_stack_size_section, RawTriple.isPS4()))
+    CmdArgs.push_back("-fstack-size-section");
+  else
+    CmdArgs.push_back("-fno-stack-size-section");
+
   CmdArgs.push_back("-ferror-limit");
   if (Arg *A = Args.getLastArg(options::OPT_ferror_limit_EQ))
     CmdArgs.push_back(A->getValue());
   else
     CmdArgs.push_back("19");
 
   if (Arg *A = Args.getLastArg(options::OPT_fmacro_backtrace_limit_EQ)) {
     CmdArgs.push_back("-fmacro-backtrace-limit");

lib/Frontend/CompilerInvocation.cpp

Diags.Report(diag::err_drv_invalid_value)
         << Opts.ThreadModel;
   Opts.TrapFuncName = Args.getLastArgValue(OPT_ftrap_function_EQ);
   Opts.UseInitArray = Args.hasArg(OPT_fuse_init_array);
 
   Opts.FunctionSections = Args.hasFlag(OPT_ffunction_sections,
                                        OPT_fno_function_sections, false);
   Opts.DataSections = Args.hasFlag(OPT_fdata_sections,
                                    OPT_fno_data_sections, false);
+  Opts.StackSizeSection = Args.hasFlag(
+      OPT_fstack_size_section, OPT_fno_stack_size_section, Triple.isPS4());
   Opts.UniqueSectionNames = Args.hasFlag(OPT_funique_section_names,
                                          OPT_fno_unique_section_names, true);
 
   Opts.MergeFunctions = Args.hasArg(OPT_fmerge_functions);
 
   Opts.NoUseJumpTables = Args.hasArg(OPT_fno_jump_tables);
 
   Opts.ProfileSampleAccurate = Args.hasArg(OPT_fprofile_sample_accurate);

test/CodeGen/stack-size-section.c

+// RUN: %clang_cc1 -triple x86_64-unknown %s -S -o - | FileCheck %s --check-prefix=CHECK-ABSENT
+// CHECK-ABSENT-NOT: section .stack_sizes
+
+// RUN: %clang_cc1 -triple x86_64-unknown -fstack-size-section %s -S -o - | FileCheck %s --check-prefix=CHECK-PRESENT
+// CHECK-PRESENT: section .stack_sizes
+
+int foo() { return 42; }

test/Driver/stack-size-section.c

+// RUN: %clang -target x86_64-unknown %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ABSENT
+// RUN: %clang -target x86_64-scei-ps4 -fno-stack-size-section %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ABSENT
+// CHECK-ABSENT-NOT: -fstack-size-section
+
+// RUN: %clang -target x86_64-unknown -fstack-size-section -### 2>&1 | FileCheck %s --check-prefix=CHECK-PRESENT
+// RUN: %clang -target x86_64-scei-ps4 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-PRESENT
+// CHECK-PRESENT: -fstack-size-section
+
+int foo() { return 42; }