[AIX] Lower intrinsic __builtin_cpu_is into AIX platform-specific code. (#80069)

On AIX OS, __builtin_cpu_is() references the runtime external variable
_system_configuration from /usr/include/sys/systemcfg.h.

ref issue:  https://github.com/llvm/llvm-project/issues/80042

7 files changed, 149 insertions, 2 deletions

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 1141188..a96f69d 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10364,6 +10364,8 @@ def err_x86_builtin_tile_arg_duplicate : Error<
 
 def err_builtin_target_unsupported : Error<
   "builtin is not supported on this target">;
+def err_builtin_aix_os_unsupported : Error<
+  "this builtin is available only on AIX 7.2 and later operating systems">;
 def err_builtin_longjmp_unsupported : Error<
   "__builtin_longjmp is not supported for the current target">;
 def err_builtin_setjmp_unsupported : Error<
diff --git a/clang/lib/Basic/Targets/PPC.cpp b/clang/lib/Basic/Targets/PPC.cpp
index 8c891cc..aebe51b 100644
--- a/clang/lib/Basic/Targets/PPC.cpp
+++ b/clang/lib/Basic/Targets/PPC.cpp
@@ -904,6 +904,16 @@ bool PPCTargetInfo::validateCpuSupports(StringRef FeatureStr) const {
 }
 
 bool PPCTargetInfo::validateCpuIs(StringRef CPUName) const {
+  llvm::Triple Triple = getTriple();
+  if (Triple.isOSAIX()) {
+#define PPC_AIX_CPU(NAME, SUPPORT, INDEX, OP, VALUE) .Case(NAME, true)
+    return llvm::StringSwitch<bool>(CPUName)
+#include "llvm/TargetParser/PPCTargetParser.def"
+        .Default(false);
+  }
+
+  assert(Triple.isOSLinux() &&
+         "__builtin_cpu_is() is only supported for AIX and Linux.");
 #define PPC_LNX_CPU(NAME, NUM) .Case(NAME, true)
   return llvm::StringSwitch<bool>(CPUName)
 #include "llvm/TargetParser/PPCTargetParser.def"
diff --git a/clang/lib/Basic/Targets/PPC.h b/clang/lib/Basic/Targets/PPC.h
index a91bded..7068391 100644
--- a/clang/lib/Basic/Targets/PPC.h
+++ b/clang/lib/Basic/Targets/PPC.h
@@ -362,8 +362,16 @@ public:
 
   // We support __builtin_cpu_supports/__builtin_cpu_is on targets that
   // have Glibc since it is Glibc that provides the HWCAP[2] in the auxv.
+  static constexpr int MINIMUM_AIX_OS_MAJOR = 7;
+  static constexpr int MINIMUM_AIX_OS_MINOR = 2;
   bool supportsCpuSupports() const override { return getTriple().isOSGlibc(); }
-  bool supportsCpuIs() const override { return getTriple().isOSGlibc(); }
+  bool supportsCpuIs() const override {
+    llvm::Triple Triple = getTriple();
+    // AIX 7.2 is the minimum requirement to support __builtin_cpu_is().
+    return Triple.isOSGlibc() ||
+           (Triple.isOSAIX() &&
+            !Triple.isOSVersionLT(MINIMUM_AIX_OS_MAJOR, MINIMUM_AIX_OS_MINOR));
+  }
   bool validateCpuSupports(StringRef Feature) const override;
   bool validateCpuIs(StringRef Name) const override;
 };
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index d454ccc..d8b2115 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -16542,12 +16542,59 @@ Value *CodeGenFunction::EmitPPCBuiltinExpr(unsigned BuiltinID,
 
   Intrinsic::ID ID = Intrinsic::not_intrinsic;
 
+#include "llvm/TargetParser/PPCTargetParser.def"
+  auto GenAIXPPCBuiltinCpuExpr = [&](unsigned SupportMethod, unsigned FieldIdx,
+                                     unsigned CompOp,
+                                     unsigned OpValue) -> Value * {
+    if (SupportMethod == AIX_BUILTIN_PPC_FALSE)
+      return llvm::ConstantInt::getFalse(ConvertType(E->getType()));
+
+    if (SupportMethod == AIX_BUILTIN_PPC_TRUE)
+      return llvm::ConstantInt::getTrue(ConvertType(E->getType()));
+
+    assert(SupportMethod <= USE_SYS_CONF && "Invalid value for SupportMethod.");
+    assert((CompOp == COMP_EQ) && "Only equal comparisons are supported.");
+
+    llvm::Type *STy = llvm::StructType::get(PPC_SYSTEMCONFIG_TYPE);
+    llvm::Constant *SysConf =
+        CGM.CreateRuntimeVariable(STy, "_system_configuration");
+
+    // Grab the appropriate field from _system_configuration.
+    llvm::Value *Idxs[] = {ConstantInt::get(Int32Ty, 0),
+                           ConstantInt::get(Int32Ty, FieldIdx)};
+
+    llvm::Value *FieldValue = Builder.CreateGEP(STy, SysConf, Idxs);
+    FieldValue = Builder.CreateAlignedLoad(Int32Ty, FieldValue,
+                                           CharUnits::fromQuantity(4));
+    assert(FieldValue->getType()->isIntegerTy(32) &&
+           "Only 32-bit integers are supported in GenAIXPPCBuiltinCpuExpr().");
+    return Builder.CreateICmp(ICmpInst::ICMP_EQ, FieldValue,
+                              ConstantInt::get(Int32Ty, OpValue));
+  };
+
   switch (BuiltinID) {
   default: return nullptr;
 
   case Builtin::BI__builtin_cpu_is: {
     const Expr *CPUExpr = E->getArg(0)->IgnoreParenCasts();
     StringRef CPUStr = cast<clang::StringLiteral>(CPUExpr)->getString();
+    llvm::Triple Triple = getTarget().getTriple();
+
+    if (Triple.isOSAIX()) {
+      unsigned IsCpuSupport, FieldIdx, CompareOp, CpuIdValue;
+      typedef std::tuple<unsigned, unsigned, unsigned, unsigned> CPUType;
+      std::tie(IsCpuSupport, FieldIdx, CompareOp, CpuIdValue) =
+          static_cast<CPUType>(StringSwitch<CPUType>(CPUStr)
+#define PPC_AIX_CPU(NAME, SUPPORT_MAGIC, INDEX, COMPARE_OP, VALUE)             \
+  .Case(NAME, {SUPPORT_MAGIC, INDEX, COMPARE_OP, VALUE})
+#include "llvm/TargetParser/PPCTargetParser.def"
+          );
+      return GenAIXPPCBuiltinCpuExpr(IsCpuSupport, FieldIdx, CompareOp,
+                                     CpuIdValue);
+    }
+
+    assert(Triple.isOSLinux() &&
+           "__builtin_cpu_is() is only supported for AIX and Linux.");
     unsigned NumCPUID = StringSwitch<unsigned>(CPUStr)
 #define PPC_LNX_CPU(Name, NumericID) .Case(Name, NumericID)
 #include "llvm/TargetParser/PPCTargetParser.def"
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index e8bfb21..710437b 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -2165,7 +2165,10 @@ static bool SemaBuiltinCpu(Sema &S, const TargetInfo &TI, CallExpr *TheCall,
     return S.Diag(TheCall->getBeginLoc(), diag::err_builtin_target_unsupported)
            << SourceRange(TheCall->getBeginLoc(), TheCall->getEndLoc());
   if (!IsCPUSupports && !TheTI->supportsCpuIs())
-    return S.Diag(TheCall->getBeginLoc(), diag::err_builtin_target_unsupported)
+    return S.Diag(TheCall->getBeginLoc(),
+                  TI.getTriple().isOSAIX()
+                      ? diag::err_builtin_aix_os_unsupported
+                      : diag::err_builtin_target_unsupported)
            << SourceRange(TheCall->getBeginLoc(), TheCall->getEndLoc());
 
   Expr *Arg = TheCall->getArg(0)->IgnoreParenImpCasts();
diff --git a/clang/test/CodeGen/aix-builtin-cpu-is.c b/clang/test/CodeGen/aix-builtin-cpu-is.c
new file mode 100644
index 0000000..b0a0dec4
--- /dev/null
+++ b/clang/test/CodeGen/aix-builtin-cpu-is.c
@@ -0,0 +1,71 @@
+// RUN: echo "int main() { return __builtin_cpu_is(\"ppc970\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"ppc-cell-be\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"ppca2\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"ppc405\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"ppc440\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"ppc464\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"ppc476\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"power4\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"power5\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"power5+\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"power6\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"power6x\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"power7\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s -DVALUE=32768 \
+// RUN:   --check-prefix=CHECKOP
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"power8\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s -DVALUE=65536 \
+// RUN:   --check-prefix=CHECKOP
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"power9\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s -DVALUE=131072\
+// RUN:   --check-prefix=CHECKOP
+
+// RUN: echo "int main() { return __builtin_cpu_is(\"power10\");}" > %t.c 
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.2.0.0 -emit-llvm -o - %t.c | FileCheck %s -DVALUE=262144 \
+// RUN:   --check-prefix=CHECKOP
+
+// CHECK:     define i32 @main() #0 {
+// CHECK-NEXT: entry:
+// CHECK-NEXT:   %retval = alloca i32, align 4
+// CHECK-NEXT:   store i32 0, ptr %retval, align 4
+// CHECK-NEXT:   ret i32 0
+// CHECK-NEXT: }
+
+// CHECKOP: @_system_configuration = external global { i32, i32, i32 }
+// CHECKOP:   define i32 @main() #0 {
+// CHECKOP-NEXT: entry:
+// CHECKOP-NEXT:   %retval = alloca i32, align 4
+// CHECKOP-NEXT:   store i32 0, ptr %retval, align 4
+// CHECKOP-NEXT:   %0 = load i32, ptr getelementptr inbounds ({ i32, i32, i32 }, ptr @_system_configuration, i32 0, i32 1), align 4
+// CHECKOP-NEXT:   %1 = icmp eq i32 %0, [[VALUE]] 
+// CHECKOP-NEXT:  %conv = zext i1 %1 to i32
+// CHECKOP-NEXT:   ret i32 %conv
+// CHECKOP-NEXT: }
+
+
diff --git a/clang/test/Sema/aix-builtin-cpu-unsupports.c b/clang/test/Sema/aix-builtin-cpu-unsupports.c
new file mode 100644
index 0000000..10e21867
--- /dev/null
+++ b/clang/test/Sema/aix-builtin-cpu-unsupports.c
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -fsyntax-only -triple  powerpc-ibm-aix7.1.0.0 -verify %s
+
+int main(void) {
+  if (__builtin_cpu_is("power8")) // expected-error {{this builtin is available only on AIX 7.2 and later operating systems}}
+    return 1;
+}