[clang][driver] Add option to manually control -disable-free in cc1

[Chenbing.Zheng]

Summary

I get a memory leak in clang's CompilerInstance::ExecuteAction,
and remove -disable-free in cc1 works according to
https://github.com/RadeonOpenCompute/ROCm-OpenCL-Driver/issues/13

So, I want to add option to manually control -disable-free in cc1.

[aaron.ballman]

Hmmm, can you explain a bit more about why you need this? By default, Clang (the application) leaks memory on shutdown (why free a whole bunch of memory only to terminate, which frees the memory for you?). So it surprises me that we'd need a *driver* option for this because the driver is how you execute clang itself (rather than using Clang as a library, which is why we have the cc1 option). So, to me, this doesn't feel strongly motivated, but I might be misunderstanding the problem you're trying to solve.

clang/include/clang/Driver/Options.td

 def fdiagnostics_show_template_tree : Flag<["-"], "fdiagnostics-show-template-tree">,
     Group<f_Group>, Flags<[CC1Option]>,
     HelpText<"Print a template comparison tree for differing templates">,
     MarshallingInfoFlag<DiagnosticOpts<"ShowTemplateTree">>;
 def fdiscard_value_names : Flag<["-"], "fdiscard-value-names">, Group<f_clang_Group>,
   HelpText<"Discard value names in LLVM IR">, Flags<[NoXarchOption]>;
 def fno_discard_value_names : Flag<["-"], "fno-discard-value-names">, Group<f_clang_Group>,
   HelpText<"Do not discard value names in LLVM IR">, Flags<[NoXarchOption]>;
+def fno_disable_free : Flag<["-"], "fno-disable-free">, Group<f_clang_Group>,
+  HelpText<"cancel disable-free in cc1">, Flags<[NoXarchOption]>;
 defm dollars_in_identifiers : BoolFOption<"dollars-in-identifiers",
   LangOpts<"DollarIdents">, Default<!strconcat("!", asm_preprocessor.KeyPath)>,
   PosFlag<SetTrue, [], "Allow">, NegFlag<SetFalse, [], "Disallow">,
   BothFlags<[CC1Option], " '$' in identifiers">>;
 def fdwarf2_cfi_asm : Flag<["-"], "fdwarf2-cfi-asm">, Group<clang_ignored_f_Group>;
 def fno_dwarf2_cfi_asm : Flag<["-"], "fno-dwarf2-cfi-asm">, Group<clang_ignored_f_Group>;
 defm dwarf_directory_asm : BoolFOption<"dwarf-directory-asm",
   CodeGenOpts<"NoDwarfDirectoryAsm">, DefaultFalse,

clang/lib/Driver/ToolChains/Clang.cpp

void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   }
 
   if (C.getDriver().embedBitcodeMarkerOnly() && !IsUsingLTO)
     CmdArgs.push_back("-fembed-bitcode=marker");
 
   // We normally speed up the clang process a bit by skipping destructors at
   // exit, but when we're generating diagnostics we can rely on some of the
   // cleanup.
-  if (!C.isForDiagnostics())
+  if (!Args.hasArg(options::OPT_fno_disable_free) && !C.isForDiagnostics())
     CmdArgs.push_back("-disable-free");
   CmdArgs.push_back("-clear-ast-before-backend");
 
 #ifdef NDEBUG
   const bool IsAssertBuild = false;
 #else
   const bool IsAssertBuild = true;
 #endif

clang/test/Driver/clang_f_opts.c

 // CHECK_JMC: -fjmc
 // CHECK_NOJMC_LTO-NOT: -plugin-opt=-enable-jmc-instrument
 // CHECK_JMC_LTO: -plugin-opt=-enable-jmc-instrument
 
 // RUN: %clang -### -fintegrated-objemitter -target x86_64 %s 2>&1 | FileCheck -check-prefix=CHECK-INT-OBJEMITTER %s
 // CHECK-INT-OBJEMITTER-NOT: unsupported option '-fintegrated-objemitter' for target
 // RUN: %clang -### -fno-integrated-objemitter -target x86_64 %s 2>&1 | FileCheck -check-prefix=CHECK-NOINT-OBJEMITTER %s
 // CHECK-NOINT-OBJEMITTER: unsupported option '-fno-integrated-objemitter' for target
+
+// RUN: %clang -### -S %s 2>&1 | FileCheck -check-prefix=CHECK-DISABLE-FREE %s
+// RUN: %clang -### -S -fno-disable-free %s 2>&1 | FileCheck -check-prefix=CHECK-NO-DISABLE-FREE %s
+// CHECK-DISABLE-FREE: "-disable-free"
+// CHECK-NO-DISABLE-FREE-NOT: "-disable-free"