[TargetParser][ARM] Account dependencies when processing target features

[labrinea]

Summary

Teaches ARM::appendArchExtFeatures to account dependencies when processing target features: i.e. when you say -march=armv8.1-m.main+mve.fp+nofp it means mve.fp should get discarded too. (Split from D63936)

[ostannard]

LGTM

[labrinea]

Added the dependency of mve on dsp and some missing tests to cover those cases.

clang/test/Preprocessor/arm-target-features.c

 
 // RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main+mve.fp -x c -E -dM %s -o - | FileCheck -match-full-lines --check-prefix=CHECK-V81M-MVE-FP %s
 // CHECK-V81M-MVE-FP: #define __ARM_FEATURE_DSP 1
 // CHECK-V81M-MVE-FP: #define __ARM_FEATURE_FP16_SCALAR_ARITHMETIC 1
 // CHECK-V81M-MVE-FP: #define __ARM_FEATURE_MVE 3
 // CHECK-V81M-MVE-FP: #define __ARM_FEATURE_SIMD32 1
 // CHECK-V81M-MVE-FP: #define __ARM_FPV5__ 1
 
+// nofp discards mve.fp
+// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main+mve.fp+nofp -x c -E -dM %s -o - | FileCheck -match-full-lines --check-prefix=CHECK-V81M-MVEFP-NOFP %s
+// CHECK-V81M-MVEFP-NOFP-NOT: #define __ARM_FEATURE_MVE
+
+// nomve discards mve.fp
+// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main+mve.fp+nomve -x c -E -dM %s -o - | FileCheck -match-full-lines --check-prefix=CHECK-V81M-MVEFP-NOMVE %s
+// CHECK-V81M-MVEFP-NOMVE-NOT: #define __ARM_FEATURE_MVE
+
 // RUN: %clang -target armv8.1a-none-none-eabi -x c -E -dM %s -o - | FileCheck -match-full-lines --check-prefix=CHECK-V81A %s
 // CHECK-V81A: #define __ARM_ARCH 8
 // CHECK-V81A: #define __ARM_ARCH_8_1A__ 1
 // CHECK-V81A: #define __ARM_ARCH_PROFILE 'A'
 // CHECK-V81A: #define __ARM_FEATURE_QRDMX 1
 // CHECK-V81A: #define __ARM_FP 0xe
 
 // RUN: %clang -target armv8.2a-none-none-eabi -x c -E -dM %s -o - | FileCheck -match-full-lines --check-prefix=CHECK-V82A %s

llvm/lib/Support/ARMTargetParser.cpp

if (CandidateFPU.FPUVer == InputFPU.FPUVer &&
       return CandidateFPU.ID;
     }
   }
 
   // nothing found
   return ARM::FK_INVALID;
 }
 
+static unsigned getAEKID(StringRef ArchExtName) {
+  for (const auto AE : ARM::ARCHExtNames)
+    if (AE.getName() == ArchExtName)
+      return AE.ID;
+  return ARM::AEK_INVALID;
+}
+
 bool ARM::appendArchExtFeatures(
   StringRef CPU, ARM::ArchKind AK, StringRef ArchExt,
   std::vector<StringRef> &Features) {
-  StringRef StandardFeature = getArchExtFeature(ArchExt);
-  if (!StandardFeature.empty()) {
-    Features.push_back(StandardFeature);
-    return true;
-  }
 
+  size_t StartingNumFeatures = Features.size();
   const bool Negated = stripNegationPrefix(ArchExt);
+  unsigned ID = getAEKID(ArchExt);
+
+  if (ID == AEK_INVALID)
+    return false;
+
+  for (const auto AE : ARCHExtNames) {
+    if (Negated && (AE.ID & ID) == ID && AE.NegFeature)
+      Features.push_back(AE.NegFeature);
+    else if (AE.ID == ID && AE.Feature)
+      Features.push_back(AE.Feature);
+  }
 
   if (CPU == "")
     CPU = "generic";
 
   if (ArchExt == "fp" || ArchExt == "fp.dp") {
     unsigned FPUKind;
     if (ArchExt == "fp.dp") {
       if (Negated) {
         Features.push_back("-fp64");
         return true;
       }
       FPUKind = findDoublePrecisionFPU(getDefaultFPU(CPU, AK));
     } else if (Negated) {
       FPUKind = ARM::FK_NONE;
     } else {
       FPUKind = getDefaultFPU(CPU, AK);
     }
     return ARM::getFPUFeatures(FPUKind, Features);
   }
-  return false;
+  return StartingNumFeatures != Features.size();
 }
 
 StringRef ARM::getHWDivName(unsigned HWDivKind) {
   for (const auto D : HWDivNames) {
     if (HWDivKind == D.ID)
       return D.getName();
   }
   return StringRef();