[PATCH] D85531: [SystemZ/ZOS] Add support for getHostNumPhysicalCores()

[Kai Nacke via Phabricator via llvm-commits]

Kai created this revision.
Kai added reviewers: uweigand, hubert.reinterpretcast, yusra.syeda, kbarton, abhina.sreeskantharajan, MaskRay, aganea.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.
Kai requested review of this revision.

The information about the CPs online in an LPAR is stored in a control block.
The code navigates to the right control block and returns the number.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D85531

Files:
  llvm/lib/Support/Host.cpp
  llvm/unittests/Support/Host.cpp


Index: llvm/unittests/Support/Host.cpp
===================================================================
--- llvm/unittests/Support/Host.cpp
+++ llvm/unittests/Support/Host.cpp
@@ -37,12 +37,13 @@
   bool isSupportedArchAndOS() {
     // Initially this is only testing detection of the number of
     // physical cores, which is currently only supported/tested for
-    // x86_64 Linux and Darwin.
+    // x86_64 Linux and Darwin and for z/OS.
     return (Host.isOSWindows() && llvm_is_multithreaded()) ||
            (Host.isX86() &&
             (Host.isOSDarwin() || Host.getOS() == Triple::Linux)) ||
            (Host.getOS() == Triple::Linux &&
-            (Host.isPPC64() || Host.isSystemZ()));
+            (Host.isPPC64() || Host.isSystemZ()) ||
+           (Host.isSystemZ() && Host.isOSzOS());
   }
 
   HostTest() : Host(Triple::normalize(sys::getProcessTriple())) {}
Index: llvm/lib/Support/Host.cpp
===================================================================
--- llvm/lib/Support/Host.cpp
+++ llvm/lib/Support/Host.cpp
@@ -1311,6 +1311,28 @@
   }
   return count;
 }
+#elif defined(__MVS__)
+int computeHostNumPhysicalCores() {
+  enum {
+    // Byte offset of the pointer to the Communications Vector Table (CVT) in
+    // the Prefixed Save Area (PSA). The table entry is a 31-bit pointer and
+    // will be zero-extended to uintptr_t.
+    FLCCVT = 16,
+    // Byte offset of the pointer to the Common System Data Area (CSD) in the
+    // CVT. The table entry is a 31-bit pointer and will be zero-extended to
+    // uintptr_t.
+    CVTCSD = 660,
+    // Byte offset to the number of live CPs in the LPAR, stored as a signed
+    // 32-bit value in the table.
+    CSD_NUMBER_ONLINE_STANDARD_CPS = 264,
+  };
+  char *PSA = 0;
+  char *CVT = reinterpret_cast<char *>(
+      static_cast<uintptr_t>(reinterpret_cast<unsigned int &>(PSA[FLCCVT])));
+  char *CSD = reinterpret_cast<char *>(
+      static_cast<uintptr_t>(reinterpret_cast<unsigned int &>(CVT[CVTCSD])));
+  return reinterpret_cast<int &>(CSD[CSD_NUMBER_ONLINE_STANDARD_CPS]);
+}
 #elif defined(_WIN32) && LLVM_ENABLE_THREADS != 0
 // Defined in llvm/lib/Support/Windows/Threading.inc
 int computeHostNumPhysicalCores();


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