Support for the mno-stack-arg-probe flag

Adds support for this flag. There is also another piece for llvm
(separate review). More info:
https://bugs.llvm.org/show_bug.cgi?id=36221

By Ruslan Nikolaev!

Differential Revision: https://reviews.llvm.org/D43108

llvm-svn: 325901

clang/docs/ClangCommandLineReference.rst

@@ -2192,6 +2192,10 @@ Set the stack alignment
 
 Set the stack probe size
 
+.. option:: -mstack-arg-probe, -mno-stack-arg-probe
+
+Disable stack probes
+
 .. option:: -mstackrealign, -mno-stackrealign
 
 Force realign the stack at entry to every function

clang/include/clang/Driver/Options.td

@@ -1842,6 +1842,10 @@ def mstack_alignment : Joined<["-"], "mstack-alignment=">, Group<m_Group>, Flags
   HelpText<"Set the stack alignment">;
 def mstack_probe_size : Joined<["-"], "mstack-probe-size=">, Group<m_Group>, Flags<[CC1Option]>,
   HelpText<"Set the stack probe size">;
+def mstack_arg_probe : Flag<["-"], "mstack-arg-probe">, Group<m_Group>,
+  HelpText<"Enable stack probes">;
+def mno_stack_arg_probe : Flag<["-"], "mno-stack-arg-probe">, Group<m_Group>, Flags<[CC1Option]>,
+  HelpText<"Disable stack probes which are enabled by default">;
 def mthread_model : Separate<["-"], "mthread-model">, Group<m_Group>, Flags<[CC1Option]>,
   HelpText<"The thread model to use, e.g. posix, single (posix by default)">, Values<"posix,single">;
 def meabi : Separate<["-"], "meabi">, Group<m_Group>, Flags<[CC1Option]>,

clang/include/clang/Frontend/CodeGenOptions.def

@@ -227,6 +227,7 @@ VALUE_CODEGENOPT(StackAlignment    , 32, 0) ///< Overrides default stack
                                             ///< alignment, if not 0.
 VALUE_CODEGENOPT(StackProbeSize    , 32, 4096) ///< Overrides default stack
                                                ///< probe size, even if 0.
+CODEGENOPT(NoStackArgProbe, 1, 0) ///< Set when -mno-stack-arg-probe is used
 CODEGENOPT(DebugColumnInfo, 1, 0) ///< Whether or not to use column information
                                   ///< in debug info.
 

clang/lib/CodeGen/TargetInfo.cpp

@@ -2351,16 +2351,15 @@ public:
   }
 };
 
-static void addStackProbeSizeTargetAttribute(const Decl *D,
-                                             llvm::GlobalValue *GV,
-                                             CodeGen::CodeGenModule &CGM) {
-  if (D && isa<FunctionDecl>(D)) {
-    if (CGM.getCodeGenOpts().StackProbeSize != 4096) {
-      llvm::Function *Fn = cast<llvm::Function>(GV);
+static void addStackProbeTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
+                                          CodeGen::CodeGenModule &CGM) {
+  if (llvm::Function *Fn = dyn_cast_or_null<llvm::Function>(GV)) {
 
+    if (CGM.getCodeGenOpts().StackProbeSize != 4096)
       Fn->addFnAttr("stack-probe-size",
                     llvm::utostr(CGM.getCodeGenOpts().StackProbeSize));
-    }
+    if (CGM.getCodeGenOpts().NoStackArgProbe)
+      Fn->addFnAttr("no-stack-arg-probe");
   }
 }
 
@@ -2369,7 +2368,7 @@ void WinX86_32TargetCodeGenInfo::setTargetAttributes(
   X86_32TargetCodeGenInfo::setTargetAttributes(D, GV, CGM);
   if (GV->isDeclaration())
     return;
-  addStackProbeSizeTargetAttribute(D, GV, CGM);
+  addStackProbeTargetAttributes(D, GV, CGM);
 }
 
 class WinX86_64TargetCodeGenInfo : public TargetCodeGenInfo {
@@ -2429,7 +2428,7 @@ void WinX86_64TargetCodeGenInfo::setTargetAttributes(
     }
   }
 
-  addStackProbeSizeTargetAttribute(D, GV, CGM);
+  addStackProbeTargetAttributes(D, GV, CGM);
 }
 }
 
@@ -5622,7 +5621,7 @@ void WindowsARMTargetCodeGenInfo::setTargetAttributes(
   ARMTargetCodeGenInfo::setTargetAttributes(D, GV, CGM);
   if (GV->isDeclaration())
     return;
-  addStackProbeSizeTargetAttribute(D, GV, CGM);
+  addStackProbeTargetAttributes(D, GV, CGM);
 }
 }
 

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4047,6 +4047,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       CmdArgs.push_back("-mstack-probe-size=0");
   }
 
+  if (!Args.hasFlag(options::OPT_mstack_arg_probe,
+                    options::OPT_mno_stack_arg_probe, true))
+    CmdArgs.push_back(Args.MakeArgString("-mno-stack-arg-probe"));
+
   if (Arg *A = Args.getLastArg(options::OPT_mrestrict_it,
                                options::OPT_mno_restrict_it)) {
     if (A->getOption().matches(options::OPT_mrestrict_it)) {

clang/lib/Frontend/CompilerInvocation.cpp

@@ -923,6 +923,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
     Opts.StackProbeSize = StackProbeSize;
   }
 
+  Opts.NoStackArgProbe = Args.hasArg(OPT_mno_stack_arg_probe);
+
   if (Arg *A = Args.getLastArg(OPT_fobjc_dispatch_method_EQ)) {
     StringRef Name = A->getValue();
     unsigned Method = llvm::StringSwitch<unsigned>(Name)

clang/test/CodeGen/stack-arg-probe.c

@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 %s -triple=i686-windows-msvc -emit-llvm -o - -mno-stack-arg-probe | FileCheck %s -check-prefix=NO-STACKPROBE
+// RUN: %clang_cc1 %s -triple=i686-windows-msvc -emit-llvm -o - | FileCheck %s -check-prefix=STACKPROBE
+
+// NO-STACKPROBE: attributes #{{[0-9]+}} = {{{.*}} "no-stack-arg-probe"
+// STACKPROBE-NOT: attributes #{{[0-9]+}} = {{{.*}} "no-stack-arg-probe"
+
+void test1() {
+}

clang/test/Driver/stack-arg-probe.c

@@ -0,0 +1,7 @@
+// RUN: %clang -### %s 2>&1 | FileCheck %s -check-prefix=STACKPROBE
+// RUN: %clang -### -mno-stack-arg-probe -mstack-arg-probe %s 2>&1 | FileCheck %s -check-prefix=STACKPROBE
+// RUN: %clang -### -mstack-arg-probe -mno-stack-arg-probe %s 2>&1 | FileCheck %s -check-prefix=NO-STACKPROBE
+// REQUIRES: clang-driver
+
+// NO-STACKPROBE: -mno-stack-arg-probe
+// STACKPROBE-NOT: -mno-stack-arg-probe