Add necessary support for storing code-model to module IR.

[cmtice]

Summary

Currently the code-model does not get saved in the module IR, so if a code model is specified when compiling with LTO, it gets lost and is not propagated properly to LTO. This patch does what is necessary in the front end to pass the code-model to the module, so that the back end can store it in the Module (see https://reviews.llvm.org/D52322 for the back-end patch).

Depends on https://reviews.llvm.org/D52322

Fixes PR33306.

[tejohnson]

Note that if you add a line like:

"Depends on D52322" in the summary that Phabricator will automatically link the two in the right way.

lib/CodeGen/CodeGenModule.cpp

569

Can you simplify by using a single constant for both of these (since handling the same)?

lib/CodeGen/CodeGenModule.h

38

Since nothing changed in this header, should this new include be moved to CodeGenModule.cpp?

test/CodeGen/codemodels.c

2

Might as well check "tiny" and "default" as well for completeness.

[cmtice]

lib/CodeGen/CodeGenModule.cpp

569

I just realized .Case("default") is not a valid case, so I will remove that and there will only be 1 constant.

test/CodeGen/codemodels.c

2

I will add a check for "tiny". "default" turns out not to be a valid option.

[cmtice]

Move include statement from CodeGenModule.h to CodeGenModule.cpp
Remove incorrect "default" case statement.
Add test for "tiny" code model.

[tejohnson]

LGTM

lib/CodeGen/CodeGenModule.h

 #include "llvm/ADT/StringMap.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/ValueHandle.h"
+#include "llvm/Support/CodeGen.h"
 #include "llvm/Transforms/Utils/SanitizerStats.h"
 
 namespace llvm {

lib/CodeGen/CodeGenModule.cpp

 #include "clang/CodeGen/ConstantInitBuilder.h"
 #include "clang/Frontend/CodeGenOptions.h"
 #include "clang/Sema/SemaDiagnostic.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/IR/CallSite.h"

       getModule().setPIELevel(static_cast<llvm::PIELevel::Level>(PLevel));
   }
 
+  if (getCodeGenOpts().CodeModel.size() > 0) {
+    unsigned CM = llvm::StringSwitch<unsigned>(getCodeGenOpts().CodeModel)
+                  .Case("tiny", llvm::CodeModel::Tiny)
+                  .Case("small", llvm::CodeModel::Small)
+                  .Case("kernel", llvm::CodeModel::Kernel)
+                  .Case("medium", llvm::CodeModel::Medium)
+                  .Case("large", llvm::CodeModel::Large)
+                  .Case("default", ~1u)
+                  .Default(~0u);
+    if ((CM != ~0u) && (CM != ~1u)) {
+      llvm::CodeModel::Model codeModel = static_cast<llvm::CodeModel::Model>(CM);
+      getModule().setCodeModel(codeModel);
+    }
+  }
+
   if (CodeGenOpts.NoPLT)
     getModule().setRtLibUseGOT();
 

test/CodeGen/codemodels.c

+// RUN: %clang_cc1 -emit-llvm  %s -o - | FileCheck %s -check-prefix=CHECK-NOMODEL
+// RUN: %clang_cc1 -emit-llvm -mcode-model small %s -o - | FileCheck %s -check-prefix=CHECK-SMALL
+// RUN: %clang_cc1 -emit-llvm -mcode-model kernel %s -o - | FileCheck %s -check-prefix=CHECK-KERNEL
+// RUN: %clang_cc1 -emit-llvm -mcode-model medium %s -o - | FileCheck %s -check-prefix=CHECK-MEDIUM
+// RUN: %clang_cc1 -emit-llvm -mcode-model large %s -o - | FileCheck %s -check-prefix=CHECK-LARGE
+
+// CHECK-SMALL: !llvm.module.flags = !{{{.*}}}
+// CHECK-SMALL: !{{[0-9]+}} = !{i32 1, !"Code Model", i32 1}
+// CHECK-KERNEL: !llvm.module.flags = !{{{.*}}}
+// CHECK-KERNEL: !{{[0-9]+}} = !{i32 1, !"Code Model", i32 2}
+// CHECK-MEDIUM: !llvm.module.flags = !{{{.*}}}
+// CHECK-MEDIUM: !{{[0-9]+}} = !{i32 1, !"Code Model", i32 3}
+// CHECK-LARGE: !llvm.module.flags = !{{{.*}}}
+// CHECK-LARGE: !{{[0-9]+}} = !{i32 1, !"Code Model", i32 4}
+// CHECK-NOMODEL-NOT: Code Model