Add support for -fpcc-struct-return. Patch by Arthur O'Dwyer!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184166 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/CodeGen/x86_32-fpcc-struct-return.c b/CodeGen/x86_32-fpcc-struct-return.c
new file mode 100644 (file)
index 0000000..6851102
--- /dev/null
+++ b/CodeGen/x86_32-fpcc-struct-return.c
@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -triple i386-apple-darwin9 -emit-llvm -o - %s | FileCheck %s --check-prefix=REG
+// RUN: %clang_cc1 -triple i386-apple-darwin9 -fpcc-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=PCC
+// RUN: %clang_cc1 -triple i386-apple-darwin9 -freg-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=REG
+// RUN: %clang_cc1 -triple i386-pc-linux-gnu -emit-llvm -o - %s | FileCheck %s --check-prefix=PCC
+// RUN: %clang_cc1 -triple i386-pc-linux-gnu -fpcc-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=PCC
+// RUN: %clang_cc1 -triple i386-pc-linux-gnu -freg-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=REG
+// RUN: %clang_cc1 -triple i386-pc-win32 -emit-llvm -o - %s | FileCheck %s --check-prefix=REG
+// RUN: %clang_cc1 -triple i386-pc-win32 -fpcc-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=PCC
+// RUN: %clang_cc1 -triple i386-pc-win32 -freg-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=REG
+
+typedef struct { int a,b,c,d; } Big;
+typedef struct { int i; } Small;
+typedef struct { short s; } Short;
+typedef struct { } ZeroSized;
+
+// CHECK: define void @returnBig
+// CHECK: ret void
+Big returnBig(Big x) { return x; }
+
+// CHECK-PCC: define void @returnSmall
+// CHECK-PCC: ret void
+// CHECK-REG: define i32 @returnSmall
+// CHECK-REG: ret i32
+Small returnSmall(Small x) { return x; }
+
+// CHECK-PCC: define void @returnShort
+// CHECK-PCC: ret void
+// CHECK-REG: define i16 @returnShort
+// CHECK-REG: ret i16
+Short returnShort(Short x) { return x; }
+
+// CHECK: define void @returnZero()
+// CHECK: ret void
+ZeroSized returnZero(ZeroSized x) { return x; }

diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index c0e4c4988e2f9e8d85ececd0336371872053d122..5eb4286cc8944871df13f3b1f1eff5b970f100b9 100644 (file)
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -687,6 +687,8 @@ def fpack_struct_EQ : Joined<["-"], "fpack-struct=">, Group<f_Group>, Flags<[CC1
   HelpText<"Specify the default maximum struct packing alignment">;
 def fpascal_strings : Flag<["-"], "fpascal-strings">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Recognize and construct Pascal-style string literals">;
+def fpcc_struct_return : Flag<["-"], "fpcc-struct-return">, Group<f_Group>, Flags<[CC1Option]>,
+  HelpText<"Override the default ABI to return all structs on the stack">;
 def fpch_preprocess : Flag<["-"], "fpch-preprocess">, Group<f_Group>;
 def fpic : Flag<["-"], "fpic">, Group<f_Group>;
 def fno_pic : Flag<["-"], "fno-pic">, Group<f_Group>;
@@ -696,6 +698,8 @@ def fprofile_arcs : Flag<["-"], "fprofile-arcs">, Group<f_Group>;
 def fprofile_generate : Flag<["-"], "fprofile-generate">, Group<f_Group>;
 def framework : Separate<["-"], "framework">, Flags<[LinkerInput]>;
 def frandom_seed_EQ : Joined<["-"], "frandom-seed=">, Group<clang_ignored_f_Group>;
+def freg_struct_return : Flag<["-"], "freg-struct-return">, Group<f_Group>, Flags<[CC1Option]>,
+  HelpText<"Override the default ABI to return small structs in registers">;
 def frtti : Flag<["-"], "frtti">, Group<f_Group>;
 def fsched_interblock : Flag<["-"], "fsched-interblock">, Group<clang_ignored_f_Group>;
 def fshort_enums : Flag<["-"], "fshort-enums">, Group<f_Group>, Flags<[CC1Option]>,

diff --git a/include/clang/Frontend/CodeGenOptions.def b/include/clang/Frontend/CodeGenOptions.def
index f6e2472cb9b7b6607e9e45e2d920da42cbe1ee29..b414d7554f267fcbbb33780834bd40c9b7e00333 100644 (file)
--- a/include/clang/Frontend/CodeGenOptions.def
+++ b/include/clang/Frontend/CodeGenOptions.def
@@ -85,6 +85,10 @@ CODEGENOPT(OmitLeafFramePointer , 1, 0) ///< Set when -momit-leaf-frame-pointer
                                         ///< enabled.
 VALUE_CODEGENOPT(OptimizationLevel, 3, 0) ///< The -O[0-4] option specified.
 VALUE_CODEGENOPT(OptimizeSize, 2, 0) ///< If -Os (==1) or -Oz (==2) is specified.
+
+  /// If -fpcc-struct-return or -freg-struct-return is specified.
+ENUM_CODEGENOPT(StructReturnConvention, StructReturnConventionKind, 2, SRCK_Default)
+
 CODEGENOPT(RelaxAll          , 1, 0) ///< Relax all machine code instructions.
 CODEGENOPT(RelaxedAliasing   , 1, 0) ///< Set when -fno-strict-aliasing is enabled.
 CODEGENOPT(StructPathTBAA    , 1, 0) ///< Whether or not to use struct-path TBAA.

diff --git a/include/clang/Frontend/CodeGenOptions.h b/include/clang/Frontend/CodeGenOptions.h
index db6b4186731c8a71e1cd9be16a76dbcbe6f722d5..6717791466a3fbd511d6ef8258fefb382fc7fce2 100644 (file)
--- a/include/clang/Frontend/CodeGenOptions.h
+++ b/include/clang/Frontend/CodeGenOptions.h
@@ -71,6 +71,12 @@ public:
     FPC_Fast        // Aggressively fuse FP ops (E.g. FMA).
   };
 
+  enum StructReturnConventionKind {
+    SRCK_Default,  // No special option was passed.
+    SRCK_OnStack,  // Small structs on the stack (-fpcc-struct-return).
+    SRCK_InRegs    // Small structs in registers (-freg-struct-return).
+  };
+
   /// The code model to use (-mcmodel).
   std::string CodeModel;
 

diff --git a/lib/CodeGen/TargetInfo.cpp b/lib/CodeGen/TargetInfo.cpp
index 09f7779146bc782f8062b2a21fca358df4d0977a..01fd8e7d79a63f744db4238cea894c3862d05182 100644 (file)
--- a/lib/CodeGen/TargetInfo.cpp
+++ b/lib/CodeGen/TargetInfo.cpp
@@ -575,6 +575,9 @@ public:
       bool d, bool p, bool w, unsigned r)
     :TargetCodeGenInfo(new X86_32ABIInfo(CGT, d, p, w, r)) {}
 
+  static bool isStructReturnInRegABI(
+      const llvm::Triple &Triple, const CodeGenOptions &Opts);
+
   void SetTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
                            CodeGen::CodeGenModule &CGM) const;
 
@@ -1293,8 +1296,9 @@ static std::string qualifyWindowsLibrary(llvm::StringRef Lib) {
 
 class WinX86_32TargetCodeGenInfo : public X86_32TargetCodeGenInfo {
 public:
-  WinX86_32TargetCodeGenInfo(CodeGen::CodeGenTypes &CGT, unsigned RegParms)
-    : X86_32TargetCodeGenInfo(CGT, false, true, true, RegParms) {}
+  WinX86_32TargetCodeGenInfo(CodeGen::CodeGenTypes &CGT,
+        bool d, bool p, bool w, unsigned RegParms)
+    : X86_32TargetCodeGenInfo(CGT, d, p, w, RegParms) {}
 
   void getDependentLibraryOption(llvm::StringRef Lib,
                                  llvm::SmallString<24> &Opt) const {
@@ -4444,6 +4448,36 @@ llvm::Value *SystemZABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
   return ResAddr;
 }
 
+bool X86_32TargetCodeGenInfo::isStructReturnInRegABI(
+    const llvm::Triple &Triple, const CodeGenOptions &Opts) {
+  assert(Triple.getArch() == llvm::Triple::x86);
+
+  switch (Opts.getStructReturnConvention()) {
+  case CodeGenOptions::SRCK_Default:
+    break;
+  case CodeGenOptions::SRCK_OnStack:  // -fpcc-struct-return
+    return false;
+  case CodeGenOptions::SRCK_InRegs:  // -freg-struct-return
+    return true;
+  }
+
+  if (Triple.isOSDarwin())
+    return true;
+
+  switch (Triple.getOS()) {
+  case llvm::Triple::Cygwin:
+  case llvm::Triple::MinGW32:
+  case llvm::Triple::AuroraUX:
+  case llvm::Triple::DragonFly:
+  case llvm::Triple::FreeBSD:
+  case llvm::Triple::OpenBSD:
+  case llvm::Triple::Bitrig:
+  case llvm::Triple::Win32:
+    return true;
+  default:
+    return false;
+  }
+}
 
 ABIArgInfo SystemZABIInfo::classifyReturnType(QualType RetTy) const {
   if (RetTy->isVoidType())
@@ -5506,31 +5540,22 @@ const TargetCodeGenInfo &CodeGenModule::getTargetCodeGenInfo() {
     return *(TheTargetCodeGenInfo = new TCETargetCodeGenInfo(Types));
 
   case llvm::Triple::x86: {
-    if (Triple.isOSDarwin())
-      return *(TheTargetCodeGenInfo =
-               new X86_32TargetCodeGenInfo(Types, true, true, false,
-                                           CodeGenOpts.NumRegisterParameters));
+    bool IsDarwinVectorABI = Triple.isOSDarwin();
+    bool IsSmallStructInRegABI =
+        X86_32TargetCodeGenInfo::isStructReturnInRegABI(Triple, CodeGenOpts);
+    bool IsWin32FloatStructABI = (Triple.getOS() == llvm::Triple::Win32);
 
-    switch (Triple.getOS()) {
-    case llvm::Triple::Cygwin:
-    case llvm::Triple::MinGW32:
-    case llvm::Triple::AuroraUX:
-    case llvm::Triple::DragonFly:
-    case llvm::Triple::FreeBSD:
-    case llvm::Triple::OpenBSD:
-    case llvm::Triple::Bitrig:
-      return *(TheTargetCodeGenInfo =
-               new X86_32TargetCodeGenInfo(Types, false, true, false,
-                                           CodeGenOpts.NumRegisterParameters));
-
-    case llvm::Triple::Win32:
+    if (Triple.getOS() == llvm::Triple::Win32) {
       return *(TheTargetCodeGenInfo =
                new WinX86_32TargetCodeGenInfo(Types,
+                                              IsDarwinVectorABI, IsSmallStructInRegABI,
+                                              IsWin32FloatStructABI,
                                               CodeGenOpts.NumRegisterParameters));
-
-    default:
+    } else {
       return *(TheTargetCodeGenInfo =
-               new X86_32TargetCodeGenInfo(Types, false, false, false,
+               new X86_32TargetCodeGenInfo(Types,
+                                           IsDarwinVectorABI, IsSmallStructInRegABI,
+                                           IsWin32FloatStructABI,
                                            CodeGenOpts.NumRegisterParameters));
     }
   }

diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index add0c623aa2f106a46ede9ad5a3a4fcc1033409e..373939cd933ab9936788edecefa3e01bfd4c1b8f 100644 (file)
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -2165,6 +2165,18 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back(A->getValue());
   }
 
+  if (Arg *A = Args.getLastArg(options::OPT_fpcc_struct_return, options::OPT_freg_struct_return)) {
+    if (getToolChain().getTriple().getArch() != llvm::Triple::x86) {
+      D.Diag(diag::err_drv_unsupported_opt_for_target)
+        << A->getSpelling() << getToolChain().getTriple().str();
+    } else if (A->getOption().matches(options::OPT_fpcc_struct_return)) {
+      CmdArgs.push_back("-fpcc-struct-return");
+    } else {
+      assert(A->getOption().matches(options::OPT_freg_struct_return));
+      CmdArgs.push_back("-freg-struct-return");
+    }
+  }
+
   if (Args.hasFlag(options::OPT_mrtd, options::OPT_mno_rtd, false))
     CmdArgs.push_back("-mrtd");
 

diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 4e62fda4a3410d2bfcff62c391b5bd42efa758e0..1407e105f24cbb7a1c2c03be8154791e3a3587c8 100644 (file)
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -478,6 +478,15 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
       Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Val;
   }
 
+  if (Arg *A = Args.getLastArg(OPT_fpcc_struct_return, OPT_freg_struct_return)) {
+    if (A->getOption().matches(OPT_fpcc_struct_return)) {
+      Opts.setStructReturnConvention(CodeGenOptions::SRCK_OnStack);
+    } else {
+      assert(A->getOption().matches(OPT_freg_struct_return));
+      Opts.setStructReturnConvention(CodeGenOptions::SRCK_InRegs);
+    }
+  }
+
   return Success;
 }
 

diff --git a/test/CodeGen/x86_32-fpcc-struct-return.c b/test/CodeGen/x86_32-fpcc-struct-return.c
new file mode 100644 (file)
index 0000000..6851102
--- /dev/null
+++ b/test/CodeGen/x86_32-fpcc-struct-return.c
@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -triple i386-apple-darwin9 -emit-llvm -o - %s | FileCheck %s --check-prefix=REG
+// RUN: %clang_cc1 -triple i386-apple-darwin9 -fpcc-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=PCC
+// RUN: %clang_cc1 -triple i386-apple-darwin9 -freg-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=REG
+// RUN: %clang_cc1 -triple i386-pc-linux-gnu -emit-llvm -o - %s | FileCheck %s --check-prefix=PCC
+// RUN: %clang_cc1 -triple i386-pc-linux-gnu -fpcc-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=PCC
+// RUN: %clang_cc1 -triple i386-pc-linux-gnu -freg-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=REG
+// RUN: %clang_cc1 -triple i386-pc-win32 -emit-llvm -o - %s | FileCheck %s --check-prefix=REG
+// RUN: %clang_cc1 -triple i386-pc-win32 -fpcc-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=PCC
+// RUN: %clang_cc1 -triple i386-pc-win32 -freg-struct-return -emit-llvm -o - %s | FileCheck %s --check-prefix=REG
+
+typedef struct { int a,b,c,d; } Big;
+typedef struct { int i; } Small;
+typedef struct { short s; } Short;
+typedef struct { } ZeroSized;
+
+// CHECK: define void @returnBig
+// CHECK: ret void
+Big returnBig(Big x) { return x; }
+
+// CHECK-PCC: define void @returnSmall
+// CHECK-PCC: ret void
+// CHECK-REG: define i32 @returnSmall
+// CHECK-REG: ret i32
+Small returnSmall(Small x) { return x; }
+
+// CHECK-PCC: define void @returnShort
+// CHECK-PCC: ret void
+// CHECK-REG: define i16 @returnShort
+// CHECK-REG: ret i16
+Short returnShort(Short x) { return x; }
+
+// CHECK: define void @returnZero()
+// CHECK: ret void
+ZeroSized returnZero(ZeroSized x) { return x; }