Add support for the x86 builtin __builtin_cpu_supports.

This matches the implementation of the gcc support for the same
feature, including checking the values set up by libgcc at runtime.
The structure looks like this:

  unsigned int __cpu_vendor;
  unsigned int __cpu_type;
  unsigned int __cpu_subtype;
  unsigned int __cpu_features[1];

with a set of enums to match various fields that are field out after
parsing the output of the cpuid instruction.
This also adds a set of errors checking for valid input (and cpu).

compiler-rt support for this and the other builtins in this family
(__builtin_cpu_init and __builtin_cpu_is) are forthcoming.

llvm-svn: 240994

1 files changed, 28 insertions, 0 deletions

diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index 16c678e9588..e496a1f6cd7 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -2215,6 +2215,7 @@ public:
     Names = AddlRegNames;
     NumNames = llvm::array_lengthof(AddlRegNames);
   }
+  bool validateCpuSupports(StringRef Name) const override;
   bool validateAsmConstraint(const char *&Name,
                              TargetInfo::ConstraintInfo &info) const override;
 
@@ -3338,6 +3339,33 @@ bool X86TargetInfo::hasFeature(StringRef Feature) const {
       .Default(false);
 }
 
+// We can't use a generic validation scheme for the features accepted here
+// versus subtarget features accepted in the target attribute because the
+// bitfield structure that's initialized in the runtime only supports the
+// below currently rather than the full range of subtarget features. (See
+// X86TargetInfo::hasFeature for a somewhat comprehensive list).
+bool X86TargetInfo::validateCpuSupports(StringRef FeatureStr) const {
+  return llvm::StringSwitch<bool>(FeatureStr)
+      .Case("cmov", true)
+      .Case("mmx", true)
+      .Case("popcnt", true)
+      .Case("sse", true)
+      .Case("sse2", true)
+      .Case("sse3", true)
+      .Case("sse4.1", true)
+      .Case("sse4.2", true)
+      .Case("avx", true)
+      .Case("avx2", true)
+      .Case("sse4a", true)
+      .Case("fma4", true)
+      .Case("xop", true)
+      .Case("fma", true)
+      .Case("avx512f", true)
+      .Case("bmi", true)
+      .Case("bmi2", true)
+      .Default(false);
+}
+
 bool
 X86TargetInfo::validateAsmConstraint(const char *&Name,
                                      TargetInfo::ConstraintInfo &Info) const {