[PowerPC][Clang] Remove constraint for initial-exec TLS mode on AIX

[qiucf]

Summary

We are going to support initial-exec TLS mode on AIX targets. Currently, initial-exec is guarded from both -ftls-model=initial-exec and __attribute__((tls_model("initial-exec"))) in clang.

This patch removes such guards so that we can get expected IR, as the first step to enable support for initial-exec.

[nemanjai]

Please provide a description justifying this change. There is no context here for the viewer to determine whether this change makes sense.

[nemanjai]

So we don't have code generation for this, but we are enabling it in the front end? What happens if we try to produce code for the IR this produces? It would make more sense to me to implement what is needed in the back end prior to allowing the front end to produce the code.

[qiucf]

Ping

[shchenz]

LGTM

clang/lib/Frontend/CompilerInvocation.cpp

if (A->getOption().matches(OPT_mlink_builtin_bitcode)) {
       F.Internalize = true;
     }
     Opts.LinkBitcodeFiles.push_back(F);
   }
 
   if (Arg *A = Args.getLastArg(OPT_ftlsmodel_EQ)) {
     if (T.isOSAIX()) {
       StringRef Name = A->getValue();
-      if (Name != "global-dynamic" && Name != "local-exec")
+      if (Name == "local-dynamic")
         Diags.Report(diag::err_aix_unsupported_tls_model) << Name;
     }
   }
 
   if (Arg *A = Args.getLastArg(OPT_fdenormal_fp_math_EQ)) {
     StringRef Val = A->getValue();
     Opts.FPDenormalMode = llvm::parseDenormalFPAttribute(Val);
     Opts.FP32DenormalMode = Opts.FPDenormalMode;

clang/lib/Sema/SemaDeclAttr.cpp

static void handleTLSModelAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
   // Check that the value.
   if (Model != "global-dynamic" && Model != "local-dynamic"
       && Model != "initial-exec" && Model != "local-exec") {
     S.Diag(LiteralLoc, diag::err_attr_tlsmodel_arg);
     return;
   }
 
   if (S.Context.getTargetInfo().getTriple().isOSAIX() &&
-      Model != "global-dynamic" && Model != "local-exec") {
+      Model == "local-dynamic") {
     S.Diag(LiteralLoc, diag::err_aix_attr_unsupported_tls_model) << Model;
     return;
   }
 
   D->addAttr(::new (S.Context) TLSModelAttr(S.Context, AL, Model));
 }
 
 static void handleRestrictAttr(Sema &S, Decl *D, const ParsedAttr &AL) {

clang/test/CodeGen/PowerPC/aix-tls-model.cpp

 // RUN: %clang_cc1 %s -triple powerpc-unknown-aix -target-cpu pwr8 -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-GD
 // RUN: %clang_cc1 %s -triple powerpc-unknown-aix -target-cpu pwr8 -ftls-model=global-dynamic -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-GD
 // RUN: not %clang_cc1 %s -triple powerpc-unknown-aix -target-cpu pwr8 -ftls-model=local-dynamic -emit-llvm 2>&1 | FileCheck %s -check-prefix=CHECK-LD-ERROR
-// RUN: not %clang_cc1 %s -triple powerpc-unknown-aix -target-cpu pwr8 -ftls-model=initial-exec -emit-llvm  2>&1 | FileCheck %s -check-prefix=CHECK-IE-ERROR
+// RUN: %clang_cc1 %s -triple powerpc-unknown-aix -target-cpu pwr8 -ftls-model=initial-exec -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-IE
 // RUN: %clang_cc1 %s -triple powerpc-unknown-aix -target-cpu pwr8 -ftls-model=local-exec -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-LE
 // RUN: %clang_cc1 %s -triple powerpc64-unknown-aix -target-cpu pwr8 -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-GD
 // RUN: %clang_cc1 %s -triple powerpc64-unknown-aix -target-cpu pwr8 -ftls-model=global-dynamic -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-GD
 // RUN: not %clang_cc1 %s -triple powerpc64-unknown-aix -target-cpu pwr8 -ftls-model=local-dynamic -emit-llvm 2>&1 | FileCheck %s -check-prefix=CHECK-LD-ERROR
-// RUN: not %clang_cc1 %s -triple powerpc64-unknown-aix -target-cpu pwr8 -ftls-model=initial-exec -emit-llvm  2>&1 | FileCheck %s -check-prefix=CHECK-IE-ERROR
+// RUN: %clang_cc1 %s -triple powerpc64-unknown-aix -target-cpu pwr8 -ftls-model=initial-exec -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-IE
 // RUN: %clang_cc1 %s -triple powerpc64-unknown-aix -target-cpu pwr8 -ftls-model=local-exec -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-LE
 
 int z1 = 0;
 int z2;
 int __thread x;
 int f() {
   static int __thread y;
   return y++;
 }
 
 // CHECK-GD: @z1 ={{.*}} global i32 0
 // CHECK-GD: @z2 ={{.*}} global i32 0
 // CHECK-GD: @x ={{.*}} thread_local global i32 0
 // CHECK-GD: @_ZZ1fvE1y = internal thread_local global i32 0
 // CHECK-LD-ERROR:  error: TLS model 'local-dynamic' is not yet supported on AIX
-// CHECK-IE-ERROR:  error: TLS model 'initial-exec' is not yet supported on AIX
+// CHECK-IE: @z1 ={{.*}} global i32 0
+// CHECK-IE: @z2 ={{.*}} global i32 0
+// CHECK-IE: @x ={{.*}} thread_local(initialexec) global i32 0
+// CHECK-IE: @_ZZ1fvE1y = internal thread_local(initialexec) global i32 0
 // CHECK-LE: @z1 ={{.*}} global i32 0
 // CHECK-LE: @z2 ={{.*}} global i32 0
 // CHECK-LE: @x ={{.*}} thread_local(localexec) global i32 0
 // CHECK-LE: @_ZZ1fvE1y = internal thread_local(localexec) global i32 0

clang/test/Sema/aix-attr-tls_model.c

 // RUN: %clang_cc1 -triple powerpc64-unknown-aix -target-cpu pwr8 -verify -fsyntax-only %s
 // RUN: %clang_cc1 -triple powerpc-unknown-aix -target-cpu pwr8 -verify -fsyntax-only %s
 
 #if !__has_attribute(tls_model)
 #error "Should support tls_model attribute"
 #endif
 
 static __thread int y __attribute((tls_model("global-dynamic"))); // no-warning
 static __thread int y __attribute((tls_model("local-dynamic"))); // expected-error {{TLS model 'local-dynamic' is not yet supported on AIX}}
-static __thread int y __attribute((tls_model("initial-exec"))); // expected-error {{TLS model 'initial-exec' is not yet supported on AIX}}
+static __thread int y __attribute((tls_model("initial-exec"))); // no-warning
 static __thread int y __attribute((tls_model("local-exec"))); // no-warning