Setting GlobalDirective in TargetAsmInfo by default rather than

providing a misleading facility. It's used once in the MIPS backend
and hardcoded as "\t.globl\t" everywhere else.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45676 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CallingConv.h

@@ -57,7 +57,12 @@ namespace CallingConv {
     /// X86_FastCall - 'fast' analog of X86_StdCall. Passes first two arguments
     /// in ECX:EDX registers, others - via stack. Callee is responsible for
     /// stack cleaning.
-    X86_FastCall = 65
+    X86_FastCall = 65,
+
+    /// X86_Ocaml - This is a weird ABI used by Objective Caml. Formally, it
+    /// supports only one to six integer/address arguments, all in-reg. It also
+    /// supports tail call emission.
+    X86_Ocaml = 66
   };
 } // End CallingConv namespace
 

include/llvm/CodeGen/LinkAllCodegenComponents.h

@@ -36,6 +36,7 @@ namespace {
 
       (void) llvm::createSimpleRegisterCoalescer();
       
+      (void) llvm::createOcamlCollector();
       (void) llvm::createShadowStackCollector();
       
       (void) llvm::createBURRListDAGScheduler(NULL, NULL, NULL);

lib/CodeGen/OcamlCollector.cpp

@@ -0,0 +1,177 @@
+//===-- OcamlCollector.cpp - Ocaml frametable emitter ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements lowering for the llvm.gc* intrinsics compatible with
+// Objective Caml 3.10.0, which uses a liveness-accurate static stack map.
+//
+//===----------------------------------------------------------------------===//
+                        
+#include "llvm/CodeGen/Collectors.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/CodeGen/Collector.h"
+#include "llvm/CodeGen/CollectorMetadata.h"
+#include "llvm/Function.h"
+#include "llvm/Module.h"
+#include "llvm/PassManager.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Target/TargetAsmInfo.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetMachine.h"
+#include <ctype.h>
+
+using namespace llvm;
+
+namespace {
+
+  class VISIBILITY_HIDDEN OcamlCollector : public Collector {
+  public:
+    OcamlCollector();
+    
+    void beginAssembly(std::ostream &OS, AsmPrinter &AP,
+                       const TargetAsmInfo &TAI);
+    
+    void finishAssembly(std::ostream &OS, AsmPrinter &AP,
+                        const TargetAsmInfo &TAI);
+  };
+  
+  CollectorRegistry::Add<OcamlCollector>
+  X("ocaml", "ocaml 3.10-compatible collector");
+  
+}
+
+// -----------------------------------------------------------------------------
+
+static void EmitCamlGlobal(const Module &M, std::ostream &OS, AsmPrinter &AP,
+                           const TargetAsmInfo &TAI, const char *Id) {
+  const std::string &MId = M.getModuleIdentifier();
+  
+  std::string Mangled;
+  Mangled += TAI.getGlobalPrefix();
+  Mangled += "caml";
+  size_t Letter = Mangled.size();
+  Mangled.append(MId.begin(), std::find(MId.begin(), MId.end(), '.'));
+  Mangled += "__";
+  Mangled += Id;
+  
+  // Capitalize the first letter of the module name.
+  Mangled[Letter] = toupper(Mangled[Letter]);
+  
+  if (const char *GlobalDirective = TAI.getGlobalDirective())
+    OS << GlobalDirective << Mangled << "\n";
+  OS << Mangled << ":\n";
+}
+
+Collector *llvm::createOcamlCollector() {
+  return new OcamlCollector();
+}
+
+OcamlCollector::OcamlCollector() {
+  NeededSafePoints = 1 << GC::PostCall;
+}
+
+void OcamlCollector::beginAssembly(std::ostream &OS, AsmPrinter &AP,
+                                   const TargetAsmInfo &TAI) {
+  AP.SwitchToTextSection(TAI.getTextSection());
+  EmitCamlGlobal(getModule(), OS, AP, TAI, "code_begin");
+  
+  AP.SwitchToDataSection(TAI.getDataSection());
+  EmitCamlGlobal(getModule(), OS, AP, TAI, "data_begin");
+}
+
+/// emitAssembly - Print the frametable. The ocaml frametable format is thus:
+/// 
+///   extern "C" struct align(sizeof(intptr_t)) {
+///     uint16_t NumDescriptors;
+///     struct align(sizeof(intptr_t)) {
+///       void *ReturnAddress;
+///       uint16_t FrameSize;
+///       uint16_t NumLiveOffsets;
+///       uint16_t LiveOffsets[NumLiveOffsets];
+///     } Descriptors[NumDescriptors];
+///   } caml${module}__frametable;
+/// 
+/// Note that this precludes programs from stack frames larger than 64K
+/// (FrameSize and LiveOffsets would overflow). FrameTablePrinter will abort if
+/// either condition is detected in a function which uses the collector.
+/// 
+void OcamlCollector::finishAssembly(std::ostream &OS, AsmPrinter &AP,
+                                    const TargetAsmInfo &TAI) {
+  const char *AddressDirective;
+  int AddressAlignLog;
+  if (AP.TM.getTargetData()->getPointerSize() == sizeof(int32_t)) {
+    AddressDirective = TAI.getData32bitsDirective();
+    AddressAlignLog = 2;
+  } else {
+    AddressDirective = TAI.getData64bitsDirective();
+    AddressAlignLog = 3;
+  }
+
+  AP.SwitchToTextSection(TAI.getTextSection());
+  EmitCamlGlobal(getModule(), OS, AP, TAI, "code_end");
+  
+  AP.SwitchToDataSection(TAI.getDataSection());
+  EmitCamlGlobal(getModule(), OS, AP, TAI, "data_end");
+  
+  OS << AddressDirective << 0; // FIXME: Why does ocaml emit this??
+  AP.EOL();
+  
+  AP.SwitchToDataSection(TAI.getDataSection());
+  EmitCamlGlobal(getModule(), OS, AP, TAI, "frametable");
+  
+  for (iterator FI = begin(), FE = end(); FI != FE; ++FI) {
+    CollectorMetadata &MD = **FI;
+    
+    OS << "\t" << TAI.getCommentString() << " live roots for "
+       << MD.getFunction().getNameStart() << "\n";
+    
+    for (CollectorMetadata::iterator PI = MD.begin(),
+                                     PE = MD.end(); PI != PE; ++PI) {
+      
+      uint64_t FrameSize = MD.getFrameSize();
+      if (FrameSize >= 2<<16) {
+        cerr << "Function '" << MD.getFunction().getNameStart()
+             << "' is too large for the ocaml collector! "
+             << "Frame size " << FrameSize << " >= 65536.\n";
+        abort(); // Very rude!
+      }
+      
+      size_t LiveCount = MD.live_size(PI);
+      if (LiveCount >= 2<<16) {
+        cerr << "Function '" << MD.getFunction().getNameStart()
+             << "' is too large for the ocaml collector! "
+             << "Live root count " << LiveCount << " >= 65536.\n";
+        abort(); // Very rude!
+      }
+      
+      OS << AddressDirective
+         << TAI.getPrivateGlobalPrefix() << "label" << PI->Num;
+      AP.EOL("call return address");
+      
+      AP.EmitInt16(FrameSize);
+      AP.EOL("stack frame size");
+      
+      AP.EmitInt16(LiveCount);
+      AP.EOL("live root count");
+      
+      for (CollectorMetadata::live_iterator LI = MD.live_begin(PI),
+                                            LE = MD.live_end(PI);
+                                            LI != LE; ++LI) {
+        assert(LI->StackOffset < 2<<16 &&
+               "GC root stack offset is outside of fixed stack frame and out "
+               "of range for Ocaml collector!");
+        
+        OS << "\t.word\t" << LI->StackOffset;
+        AP.EOL("stack offset");
+      }
+      
+      AP.EmitAlignment(AddressAlignLog);
+    }
+  }
+}

test/CodeGen/Generic/GC/frame_size.ll

@@ -0,0 +1,14 @@
+; RUN: llvm-as < %s | llc -asm-verbose | grep {frame size} | grep -v 0x0
+
+declare void @llvm.gcroot(i8** %value, i8* %tag)
+declare void @g() gc "ocaml"
+
+define void @f(i8* %arg.0, void()* %arg.1) gc "ocaml" {
+entry:
+	%gcroot.0 = alloca i8*
+	call void @llvm.gcroot(i8** %gcroot.0, i8* null)
+	store i8* %arg.0, i8** %gcroot.0
+	call void @g()
+	call void %arg.1()
+	ret void
+}

test/CodeGen/Generic/GC/simple_ocaml.ll

@@ -0,0 +1,42 @@
+; RUN: llvm-as < %s | llc | grep caml.*__frametable
+; RUN: llvm-as < %s | llc -march=x86 | grep {movl	.0}
+
+%struct.obj = type { i8*, %struct.obj* }
+
+define %struct.obj* @fun(%struct.obj* %head) gc "ocaml" {
+entry:
+	%gcroot.0 = alloca i8*
+	%gcroot.1 = alloca i8*
+	
+	call void @llvm.gcroot(i8** %gcroot.0, i8* null)
+	call void @llvm.gcroot(i8** %gcroot.1, i8* null)
+	
+	%local.0 = bitcast i8** %gcroot.0 to %struct.obj**
+	%local.1 = bitcast i8** %gcroot.1 to %struct.obj**
+
+	store %struct.obj* %head, %struct.obj** %local.0
+	br label %bb.loop
+bb.loop:
+	%t0 = load %struct.obj** %local.0
+	%t1 = getelementptr %struct.obj* %t0, i32 0, i32 1
+	%t2 = bitcast %struct.obj* %t0 to i8*
+	%t3 = bitcast %struct.obj** %t1 to i8**
+	%t4 = call i8* @llvm.gcread(i8* %t2, i8** %t3)
+	%t5 = bitcast i8* %t4 to %struct.obj*
+	%t6 = icmp eq %struct.obj* %t5, null
+	br i1 %t6, label %bb.loop, label %bb.end
+bb.end:
+	%t7 = malloc %struct.obj
+	store %struct.obj* %t7, %struct.obj** %local.1
+	%t8 = bitcast %struct.obj* %t7 to i8*
+	%t9 = load %struct.obj** %local.0
+	%t10 = getelementptr %struct.obj* %t9, i32 0, i32 1
+	%t11 = bitcast %struct.obj* %t9 to i8*
+	%t12 = bitcast %struct.obj** %t10 to i8**
+	call void @llvm.gcwrite(i8* %t8, i8* %t11, i8** %t12)
+	ret %struct.obj* %t7
+}
+
+declare void @llvm.gcroot(i8** %value, i8* %tag)
+declare void @llvm.gcwrite(i8* %value, i8* %obj, i8** %field)
+declare i8* @llvm.gcread(i8* %obj, i8** %field)