[ARM] Add knowledge of FPU subtarget features to TargetParser

Add getFPUFeatures to TargetParser, which gets the list of subtarget features
that are enabled/disabled for each FPU, and use it when handling the .fpu
directive.

No functional change in this commit, though clang will start behaving
differently once it starts using this.

Differential Revision: http://reviews.llvm.org/D10237

llvm-svn: 239150

1 files changed, 110 insertions, 15 deletions

diff --git a/llvm/lib/Support/TargetParser.cpp b/llvm/lib/Support/TargetParser.cpp
index 9e81763603f..c2f521f323c 100644
--- a/llvm/lib/Support/TargetParser.cpp
+++ b/llvm/lib/Support/TargetParser.cpp
@@ -22,27 +22,33 @@ using namespace llvm;
 
 namespace {
 
-// List of canonical FPU names (use getFPUSynonym).
+// List of canonical FPU names (use getFPUSynonym) and which architectural
+// features they correspond to (use getFPUFeatures).
 // FIXME: TableGen this.
 struct {
   const char * Name;
   ARM::FPUKind ID;
+  unsigned FPUVersion; //< Corresponds directly to the FP arch version number.
+  ARM::NeonSupportLevel NeonSupport;
+  ARM::FPURestriction Restriction;
 } FPUNames[] = {
-  { "invalid",              ARM::FK_INVALID },
-  { "vfp",                  ARM::FK_VFP },
-  { "vfpv2",                ARM::FK_VFPV2 },
-  { "vfpv3",                ARM::FK_VFPV3 },
-  { "vfpv3-d16",            ARM::FK_VFPV3_D16 },
-  { "vfpv4",                ARM::FK_VFPV4 },
-  { "vfpv4-d16",            ARM::FK_VFPV4_D16 },
-  { "fpv5-d16",             ARM::FK_FPV5_D16 },
-  { "fp-armv8",             ARM::FK_FP_ARMV8 },
-  { "neon",                 ARM::FK_NEON },
-  { "neon-vfpv4",           ARM::FK_NEON_VFPV4 },
-  { "neon-fp-armv8",        ARM::FK_NEON_FP_ARMV8 },
-  { "crypto-neon-fp-armv8", ARM::FK_CRYPTO_NEON_FP_ARMV8 },
-  { "softvfp",              ARM::FK_SOFTVFP }
+  { "invalid",       ARM::FK_INVALID,       0, ARM::NS_None,   ARM::FR_None},
+  { "vfp",           ARM::FK_VFP,           2, ARM::NS_None,   ARM::FR_None},
+  { "vfpv2",         ARM::FK_VFPV2,         2, ARM::NS_None,   ARM::FR_None},
+  { "vfpv3",         ARM::FK_VFPV3,         3, ARM::NS_None,   ARM::FR_None},
+  { "vfpv3-d16",     ARM::FK_VFPV3_D16,     3, ARM::NS_None,   ARM::FR_D16},
+  { "vfpv4",         ARM::FK_VFPV4,         4, ARM::NS_None,   ARM::FR_None},
+  { "vfpv4-d16",     ARM::FK_VFPV4_D16,     4, ARM::NS_None,   ARM::FR_D16},
+  { "fpv5-d16",      ARM::FK_FPV5_D16,      5, ARM::NS_None,   ARM::FR_D16},
+  { "fp-armv8",      ARM::FK_FP_ARMV8,      5, ARM::NS_None,   ARM::FR_None},
+  { "neon",          ARM::FK_NEON,          3, ARM::NS_Neon,   ARM::FR_None},
+  { "neon-vfpv4",    ARM::FK_NEON_VFPV4,    4, ARM::NS_Neon,   ARM::FR_None},
+  { "neon-fp-armv8", ARM::FK_NEON_FP_ARMV8, 5, ARM::NS_Neon,   ARM::FR_None},
+  { "crypto-neon-fp-armv8",
+              ARM::FK_CRYPTO_NEON_FP_ARMV8, 5, ARM::NS_Crypto, ARM::FR_None},
+  { "softvfp",       ARM::FK_SOFTVFP,       0, ARM::NS_None,   ARM::FR_None},
 };
+
 // List of canonical arch names (use getArchSynonym).
 // This table also provides the build attribute fields for CPU arch
 // and Arch ID, according to the Addenda to the ARM ABI, chapters
@@ -226,6 +232,95 @@ const char *ARMTargetParser::getFPUName(unsigned FPUKind) {
   return FPUNames[FPUKind].Name;
 }
 
+unsigned ARMTargetParser::getFPUVersion(unsigned FPUKind) {
+  if (FPUKind >= ARM::FK_LAST)
+    return 0;
+  return FPUNames[FPUKind].FPUVersion;
+}
+
+unsigned getFPUNeonSupportLevel(unsigned FPUKind) {
+  if (FPUKind >= ARM::FK_LAST)
+    return 0;
+  return FPUNames[FPUKind].NeonSupport;
+}
+
+unsigned getFPURestriction(unsigned FPUKind) {
+  if (FPUKind >= ARM::FK_LAST)
+    return 0;
+  return FPUNames[FPUKind].Restriction;
+}
+
+bool ARMTargetParser::getFPUFeatures(unsigned FPUKind,
+                                     std::vector<const char *> &Features) {
+
+  if (FPUKind >= ARM::FK_LAST || FPUKind == ARM::FK_INVALID)
+    return false;
+
+  // fp-only-sp and d16 subtarget features are independent of each other, so we
+  // must enable/disable both.
+  switch (FPUNames[FPUKind].Restriction) {
+  case ARM::FR_SP_D16:
+    Features.push_back("+fp-only-sp");
+    Features.push_back("+d16");
+    break;
+  case ARM::FR_D16:
+    Features.push_back("-fp-only-sp");
+    Features.push_back("+d16");
+    break;
+  case ARM::FR_None:
+    Features.push_back("-fp-only-sp");
+    Features.push_back("-d16");
+    break;
+  }
+
+  // FPU version subtarget features are inclusive of lower-numbered ones, so
+  // enable the one corresponding to this version and disable all that are
+  // higher.
+  switch (FPUNames[FPUKind].FPUVersion) {
+  case 5:
+    Features.push_back("+fp-armv8");
+    break;
+  case 4:
+    Features.push_back("+vfp4");
+    Features.push_back("-fp-armv8");
+    break;
+  case 3:
+    Features.push_back("+vfp3");
+    Features.push_back("-vfp4");
+    Features.push_back("-fp-armv8");
+    break;
+  case 2:
+    Features.push_back("+vfp2");
+    Features.push_back("-vfp3");
+    Features.push_back("-vfp4");
+    Features.push_back("-fp-armv8");
+    break;
+  case 0:
+    Features.push_back("-vfp2");
+    Features.push_back("-vfp3");
+    Features.push_back("-vfp4");
+    Features.push_back("-fp-armv8");
+    break;
+  }
+
+  // crypto includes neon, so we handle this similarly to FPU version.
+  switch (FPUNames[FPUKind].NeonSupport) {
+  case ARM::NS_Crypto:
+    Features.push_back("+crypto");
+    break;
+  case ARM::NS_Neon:
+    Features.push_back("+neon");
+    Features.push_back("-crypto");
+    break;
+  case ARM::NS_None:
+    Features.push_back("-neon");
+    Features.push_back("-crypto");
+    break;
+  }
+
+  return true;
+}
+
 const char *ARMTargetParser::getArchName(unsigned ArchKind) {
   if (ArchKind >= ARM::AK_LAST)
     return nullptr;