It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCSubtarget.cpp b/lib/Target/PowerPC/PPCSubtarget.cpp
new file mode 100644
index 0000000..4419d20
--- /dev/null
+++ b/lib/Target/PowerPC/PPCSubtarget.cpp
@@ -0,0 +1,141 @@
+//===- PowerPCSubtarget.cpp - PPC Subtarget Information -------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Nate Begeman and is distributed under the
+// University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the PPC specific subclass of TargetSubtarget.
+//
+//===----------------------------------------------------------------------===//
+
+#include "PPCSubtarget.h"
+#include "PPC.h"
+#include "llvm/Module.h"
+#include "llvm/Target/TargetMachine.h"
+#include "PPCGenSubtarget.inc"
+using namespace llvm;
+
+#if defined(__APPLE__)
+#include <mach/mach.h>
+#include <mach/mach_host.h>
+#include <mach/host_info.h>
+#include <mach/machine.h>
+
+/// GetCurrentPowerPCFeatures - Returns the current CPUs features.
+static const char *GetCurrentPowerPCCPU() {
+  host_basic_info_data_t hostInfo;
+  mach_msg_type_number_t infoCount;
+
+  infoCount = HOST_BASIC_INFO_COUNT;
+  host_info(mach_host_self(), HOST_BASIC_INFO, (host_info_t)&hostInfo, 
+            &infoCount);
+            
+  if (hostInfo.cpu_type != CPU_TYPE_POWERPC) return "generic";
+
+  switch(hostInfo.cpu_subtype) {
+  case CPU_SUBTYPE_POWERPC_601:   return "601";
+  case CPU_SUBTYPE_POWERPC_602:   return "602";
+  case CPU_SUBTYPE_POWERPC_603:   return "603";
+  case CPU_SUBTYPE_POWERPC_603e:  return "603e";
+  case CPU_SUBTYPE_POWERPC_603ev: return "603ev";
+  case CPU_SUBTYPE_POWERPC_604:   return "604";
+  case CPU_SUBTYPE_POWERPC_604e:  return "604e";
+  case CPU_SUBTYPE_POWERPC_620:   return "620";
+  case CPU_SUBTYPE_POWERPC_750:   return "750";
+  case CPU_SUBTYPE_POWERPC_7400:  return "7400";
+  case CPU_SUBTYPE_POWERPC_7450:  return "7450";
+  case CPU_SUBTYPE_POWERPC_970:   return "970";
+  default: ;
+  }
+  
+  return "generic";
+}
+#endif
+
+
+PPCSubtarget::PPCSubtarget(const TargetMachine &tm, const Module &M,
+                           const std::string &FS, bool is64Bit)
+  : TM(tm)
+  , StackAlignment(16)
+  , IsGigaProcessor(false)
+  , Has64BitSupport(false)
+  , Use64BitRegs(false)
+  , IsPPC64(is64Bit)
+  , HasAltivec(false)
+  , HasFSQRT(false)
+  , HasSTFIWX(false)
+  , IsDarwin(false)
+  , HasLazyResolverStubs(false) {
+
+  // Determine default and user specified characteristics
+  std::string CPU = "generic";
+#if defined(__APPLE__)
+  CPU = GetCurrentPowerPCCPU();
+#endif
+
+  // Parse features string.
+  ParseSubtargetFeatures(FS, CPU);
+
+  // If we are generating code for ppc64, verify that options make sense.
+  if (is64Bit) {
+    if (!has64BitSupport()) {
+      cerr << "PPC: Generation of 64-bit code for a 32-bit processor "
+           << "requested.  Ignoring 32-bit processor feature.\n";
+      Has64BitSupport = true;
+    }
+    // Silently force 64-bit register use on ppc64.
+    Use64BitRegs = true;
+  }
+  
+  // If the user requested use of 64-bit regs, but the cpu selected doesn't
+  // support it, warn and ignore.
+  if (use64BitRegs() && !has64BitSupport()) {
+    cerr << "PPC: 64-bit registers requested on CPU without support.  "
+         << "Disabling 64-bit register use.\n";
+    Use64BitRegs = false;
+  }
+  
+  // Set the boolean corresponding to the current target triple, or the default
+  // if one cannot be determined, to true.
+  const std::string& TT = M.getTargetTriple();
+  if (TT.length() > 5) {
+    IsDarwin = TT.find("-darwin") != std::string::npos;
+  } else if (TT.empty()) {
+#if defined(__APPLE__)
+    IsDarwin = true;
+#endif
+  }
+
+  // Set up darwin-specific properties.
+  if (IsDarwin) {
+    HasLazyResolverStubs = true;
+    AsmFlavor = NewMnemonic;
+  } else {
+    AsmFlavor = OldMnemonic;
+  }
+}
+
+/// SetJITMode - This is called to inform the subtarget info that we are
+/// producing code for the JIT.
+void PPCSubtarget::SetJITMode() {
+  // JIT mode doesn't want lazy resolver stubs, it knows exactly where
+  // everything is.  This matters for PPC64, which codegens in PIC mode without
+  // stubs.
+  HasLazyResolverStubs = false;
+}
+
+
+/// hasLazyResolverStub - Return true if accesses to the specified global have
+/// to go through a dyld lazy resolution stub.  This means that an extra load
+/// is required to get the address of the global.
+bool PPCSubtarget::hasLazyResolverStub(const GlobalValue *GV) const {
+  // We never hae stubs if HasLazyResolverStubs=false or if in static mode.
+  if (!HasLazyResolverStubs || TM.getRelocationModel() == Reloc::Static)
+    return false;
+  
+  return GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
+         (GV->isDeclaration() && !GV->hasNotBeenReadFromBitcode());
+}