Introduce code_model macros

Summary:
gcc defines macros such as __code_model_small_ based on the user passed command line flag -mcmodel. clang accepts a flag with the same name and similar effects, but does not generate any macro that the user can use. This cl narrows the gap between gcc and clang behaviour.

However, achieving full compatibility with gcc is not trivial: The set of valid values for mcmodel in gcc and clang are not equal. Also, gcc defines different macros for different architectures. In this cl, we only tackle an easy part of the problem and define the macro only for x64 architecture. When the user does not specify a mcmodel, the macro for small code model is produced, as is the case with gcc.

Reviewers: compnerd, MaskRay

Reviewed By: MaskRay

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D52920

llvm-svn: 344000

clang/include/clang/Basic/TargetOptions.h

@@ -67,6 +67,12 @@ public:
   /// \brief If enabled, use 32-bit pointers for accessing const/local/shared
   /// address space.
   bool NVPTXUseShortPointers = false;
+
+  // The code model to be used as specified by the user. Corresponds to
+  // CodeModel::Model enum defined in include/llvm/Support/CodeGen.h, plus
+  // "default" for the case when the user has not explicitly specified a
+  // code model.
+  std::string CodeModel;
 };
 
 }  // end namespace clang

clang/lib/Basic/Targets/X86.cpp

@@ -860,6 +860,11 @@ bool X86TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
 /// definitions for this particular subtarget.
 void X86TargetInfo::getTargetDefines(const LangOptions &Opts,
                                      MacroBuilder &Builder) const {
+  std::string CodeModel = getTargetOpts().CodeModel;
+  if (CodeModel == "default")
+    CodeModel = "small";
+  Builder.defineMacro("__code_model_" + CodeModel + "_");
+
   // Target identification.
   if (getTriple().getArch() == llvm::Triple::x86_64) {
     Builder.defineMacro("__amd64__");

clang/lib/Frontend/CompilerInvocation.cpp

@@ -669,7 +669,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.RegisterGlobalDtorsWithAtExit =
       Args.hasArg(OPT_fregister_global_dtors_with_atexit);
   Opts.CXXCtorDtorAliases = Args.hasArg(OPT_mconstructor_aliases);
-  Opts.CodeModel = getCodeModel(Args, Diags);
+  Opts.CodeModel = TargetOpts.CodeModel;
   Opts.DebugPass = Args.getLastArgValue(OPT_mdebug_pass);
   Opts.DisableFPElim =
       (Args.hasArg(OPT_mdisable_fp_elim) || Args.hasArg(OPT_pg));
@@ -2975,6 +2975,7 @@ static void ParsePreprocessorOutputArgs(PreprocessorOutputOptions &Opts,
 
 static void ParseTargetArgs(TargetOptions &Opts, ArgList &Args,
                             DiagnosticsEngine &Diags) {
+  Opts.CodeModel = getCodeModel(Args, Diags);
   Opts.ABI = Args.getLastArgValue(OPT_target_abi);
   if (Arg *A = Args.getLastArg(OPT_meabi)) {
     StringRef Value = A->getValue();

clang/test/Preprocessor/init.c

@@ -47,21 +47,21 @@
 // CXX11:#define __cplusplus 201103L
 // CXX11:#define __private_extern__ extern
 //
-// 
+//
 // RUN: %clang_cc1 -x c++ -std=c++98 -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix CXX98 %s
-// 
+//
 // CXX98:#define __GNUG__ {{.*}}
 // CXX98:#define __GXX_RTTI 1
 // CXX98:#define __GXX_WEAK__ 1
 // CXX98:#define __cplusplus 199711L
 // CXX98:#define __private_extern__ extern
 //
-// 
+//
 // RUN: %clang_cc1 -fdeprecated-macro -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix DEPRECATED %s
 //
 // DEPRECATED:#define __DEPRECATED 1
 //
-// 
+//
 // RUN: %clang_cc1 -std=c99 -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix C99 %s
 //
 // C99:#define __STDC_VERSION__ 199901L
@@ -71,7 +71,7 @@
 // C99-NOT: __GXX_WEAK__
 // C99-NOT: __cplusplus
 //
-// 
+//
 // RUN: %clang_cc1 -std=c11 -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix C11 %s
 // RUN: %clang_cc1 -std=c1x -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix C11 %s
 // RUN: %clang_cc1 -std=iso9899:2011 -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix C11 %s
@@ -86,7 +86,7 @@
 // C11-NOT: __GXX_WEAK__
 // C11-NOT: __cplusplus
 //
-// 
+//
 // RUN: %clang_cc1 -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix COMMON %s
 //
 // COMMON:#define __CONSTANT_CFSTRINGS__ 1
@@ -113,7 +113,7 @@
 // RUN: %clang_cc1 -E -dM -triple=x86_64-pc-linux-gnu < /dev/null | FileCheck -match-full-lines -check-prefix C-DEFAULT %s
 // RUN: %clang_cc1 -E -dM -triple=x86_64-apple-darwin < /dev/null | FileCheck -match-full-lines -check-prefix C-DEFAULT %s
 // RUN: %clang_cc1 -E -dM -triple=armv7a-apple-darwin < /dev/null | FileCheck -match-full-lines -check-prefix C-DEFAULT %s
-// 
+//
 // C-DEFAULT:#define __STDC_VERSION__ 201112L
 //
 // RUN: %clang_cc1 -ffreestanding -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix FREESTANDING %s
@@ -158,12 +158,12 @@
 // GXX98:#define __cplusplus 199711L
 // GXX98:#define __private_extern__ extern
 //
-// 
+//
 // RUN: %clang_cc1 -std=iso9899:199409 -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix C94 %s
 //
 // C94:#define __STDC_VERSION__ 199409L
 //
-// 
+//
 // RUN: %clang_cc1 -fms-extensions -triple i686-pc-win32 -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix MSEXT %s
 //
 // MSEXT-NOT:#define __STDC__
@@ -185,7 +185,7 @@
 // MSEXT-CXX-NOWCHAR-NOT:#define _WCHAR_T_DEFINED 1
 // MSEXT-CXX-NOWCHAR:#define __BOOL_DEFINED 1
 //
-// 
+//
 // RUN: %clang_cc1 -x objective-c -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix OBJC %s
 //
 // OBJC:#define OBJC_NEW_PROPERTIES 1
@@ -197,7 +197,7 @@
 //
 // OBJCGC:#define __OBJC_GC__ 1
 //
-// 
+//
 // RUN: %clang_cc1 -x objective-c -fobjc-exceptions -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix NONFRAGILE %s
 //
 // NONFRAGILE:#define OBJC_ZEROCOST_EXCEPTIONS 1
@@ -246,9 +246,9 @@
 //
 // PASCAL:#define __PASCAL_STRINGS__ 1
 //
-// 
+//
 // RUN: %clang_cc1 -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix SCHAR %s
-// 
+//
 // SCHAR:#define __STDC__ 1
 // SCHAR-NOT:#define __UNSIGNED_CHAR__
 // SCHAR:#define __clang__ 1
@@ -7978,6 +7978,7 @@
 // X86_64:#define __WINT_WIDTH__ 32
 // X86_64:#define __amd64 1
 // X86_64:#define __amd64__ 1
+// X86_64:#define __code_model_small_ 1
 // X86_64:#define __x86_64 1
 // X86_64:#define __x86_64__ 1
 //
@@ -7987,7 +7988,10 @@
 // X86_64H:#define __x86_64__ 1
 // X86_64H:#define __x86_64h 1
 // X86_64H:#define __x86_64h__ 1
-
+//
+// RUN: %clang -xc - -E -dM -mcmodel=medium --target=i386-unknown-linux < /dev/null | FileCheck -match-full-lines -check-prefix X86_MEDIUM %s
+// X86_MEDIUM:#define __code_model_medium_ 1
+//
 // RUN: %clang_cc1 -E -dM -ffreestanding -triple=x86_64-none-none-gnux32 < /dev/null | FileCheck -match-full-lines -check-prefix X32 %s
 // RUN: %clang_cc1 -x c++ -E -dM -ffreestanding -triple=x86_64-none-none-gnux32 < /dev/null | FileCheck -match-full-lines -check-prefix X32 -check-prefix X32-CXX %s
 //
@@ -9830,7 +9834,7 @@
 // AVR:#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
 // AVR:#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 1
 // AVR:#define __GXX_ABI_VERSION 1002
-// AVR:#define __INT16_C_SUFFIX__ 
+// AVR:#define __INT16_C_SUFFIX__
 // AVR:#define __INT16_MAX__ 32767
 // AVR:#define __INT16_TYPE__ short
 // AVR:#define __INT32_C_SUFFIX__ L
@@ -9839,7 +9843,7 @@
 // AVR:#define __INT64_C_SUFFIX__ LL
 // AVR:#define __INT64_MAX__ 9223372036854775807LL
 // AVR:#define __INT64_TYPE__ long long int
-// AVR:#define __INT8_C_SUFFIX__ 
+// AVR:#define __INT8_C_SUFFIX__
 // AVR:#define __INT8_MAX__ 127
 // AVR:#define __INT8_TYPE__ signed char
 // AVR:#define __INTMAX_C_SUFFIX__ LL
@@ -9914,7 +9918,7 @@
 // AVR:#define __UINT64_C_SUFFIX__ ULL
 // AVR:#define __UINT64_MAX__ 18446744073709551615ULL
 // AVR:#define __UINT64_TYPE__ long long unsigned int
-// AVR:#define __UINT8_C_SUFFIX__ 
+// AVR:#define __UINT8_C_SUFFIX__
 // AVR:#define __UINT8_MAX__ 255
 // AVR:#define __UINT8_TYPE__ unsigned char
 // AVR:#define __UINTMAX_C_SUFFIX__ ULL
@@ -9938,7 +9942,7 @@
 // AVR:#define __UINT_LEAST64_TYPE__ long long unsigned int
 // AVR:#define __UINT_LEAST8_MAX__ 255
 // AVR:#define __UINT_LEAST8_TYPE__ unsigned char
-// AVR:#define __USER_LABEL_PREFIX__ 
+// AVR:#define __USER_LABEL_PREFIX__
 // AVR:#define __WCHAR_MAX__ 32767
 // AVR:#define __WCHAR_TYPE__ int
 // AVR:#define __WINT_TYPE__ int