[llvm] r183790 - Make host ARM CPU feature detection independent of the vendor

[Tobias Grosser]

Author: grosser
Date: Tue Jun 11 16:45:01 2013
New Revision: 183790

URL: http://llvm.org/viewvc/llvm-project?rev=183790&view=rev
Log:
Make host ARM CPU feature detection independent of the vendor

For ARM on linux we use /proc/cpuinfo to detect the host CPU's features.
Linux derives these values without ever looking at the vendor of the
specific CPU implementation. Hence, it adds little value, if we parse
the output of /proc/cpuinfo only for certain vendors.

This patch enables us to derive the correct feature flags e.g. for Qualcomm
CPUs.

Modified:
    llvm/trunk/lib/Support/Host.cpp

Modified: llvm/trunk/lib/Support/Host.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Host.cpp?rev=183790&r1=183789&r2=183790&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Host.cpp (original)
+++ llvm/trunk/lib/Support/Host.cpp Tue Jun 11 16:45:01 2013
@@ -570,41 +570,31 @@ bool sys::getHostCPUFeatures(StringMap<b
   SmallVector<StringRef, 32> Lines;
   Str.split(Lines, "\n");
 
-  // Look for the CPU implementer line.
-  StringRef Implementer;
-  for (unsigned I = 0, E = Lines.size(); I != E; ++I)
-    if (Lines[I].startswith("CPU implementer"))
-      Implementer = Lines[I].substr(15).ltrim("\t :");
-
-  if (Implementer == "0x41") { // ARM Ltd.
-    SmallVector<StringRef, 32> CPUFeatures;
-
-    // Look for the CPU features.
-    for (unsigned I = 0, E = Lines.size(); I != E; ++I)
-      if (Lines[I].startswith("Features")) {
-        Lines[I].split(CPUFeatures, " ");
-        break;
-      }
+  SmallVector<StringRef, 32> CPUFeatures;
 
-    for (unsigned I = 0, E = CPUFeatures.size(); I != E; ++I) {
-      StringRef LLVMFeatureStr = StringSwitch<StringRef>(CPUFeatures[I])
-        .Case("half", "fp16")
-        .Case("neon", "neon")
-        .Case("vfpv3", "vfp3")
-        .Case("vfpv3d16", "d16")
-        .Case("vfpv4", "vfp4")
-        .Case("idiva", "hwdiv-arm")
-        .Case("idivt", "hwdiv")
-        .Default("");
-
-      if (LLVMFeatureStr != "")
-        Features.GetOrCreateValue(LLVMFeatureStr).setValue(true);
+  // Look for the CPU features.
+  for (unsigned I = 0, E = Lines.size(); I != E; ++I)
+    if (Lines[I].startswith("Features")) {
+      Lines[I].split(CPUFeatures, " ");
+      break;
     }
 
-    return true;
+  for (unsigned I = 0, E = CPUFeatures.size(); I != E; ++I) {
+    StringRef LLVMFeatureStr = StringSwitch<StringRef>(CPUFeatures[I])
+      .Case("half", "fp16")
+      .Case("neon", "neon")
+      .Case("vfpv3", "vfp3")
+      .Case("vfpv3d16", "d16")
+      .Case("vfpv4", "vfp4")
+      .Case("idiva", "hwdiv-arm")
+      .Case("idivt", "hwdiv")
+      .Default("");
+
+    if (LLVMFeatureStr != "")
+      Features.GetOrCreateValue(LLVMFeatureStr).setValue(true);
   }
 
-  return false;
+  return true;
 }
 #else
 bool sys::getHostCPUFeatures(StringMap<bool> &Features){