[llvm] r193008 - Update to reflect current GC APIs and usage. The example code is taken from the Erlang GC implementation.
Bill Wendling
isanbard at gmail.com
Fri Oct 18 16:09:06 PDT 2013
Author: void
Date: Fri Oct 18 18:09:06 2013
New Revision: 193008
URL: http://llvm.org/viewvc/llvm-project?rev=193008&view=rev
Log:
Update to reflect current GC APIs and usage. The example code is taken from the Erlang GC implementation.
Modified:
llvm/trunk/docs/GarbageCollection.rst
Modified: llvm/trunk/docs/GarbageCollection.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/GarbageCollection.rst?rev=193008&r1=193007&r2=193008&view=diff
==============================================================================
--- llvm/trunk/docs/GarbageCollection.rst (original)
+++ llvm/trunk/docs/GarbageCollection.rst Fri Oct 18 18:09:06 2013
@@ -523,7 +523,7 @@ extension):
$ cat sample.ll
define void @f() gc "mygc" {
entry:
- ret void
+ ret void
}
$ llvm-as < sample.ll | llc -load=MyGC.so
@@ -896,11 +896,9 @@ in the JIT, nor using the object writers
namespace {
class LLVM_LIBRARY_VISIBILITY MyGCPrinter : public GCMetadataPrinter {
public:
- virtual void beginAssembly(std::ostream &OS, AsmPrinter &AP,
- const TargetAsmInfo &TAI);
+ virtual void beginAssembly(AsmPrinter &AP);
- virtual void finishAssembly(std::ostream &OS, AsmPrinter &AP,
- const TargetAsmInfo &TAI);
+ virtual void finishAssembly(AsmPrinter &AP);
};
GCMetadataPrinterRegistry::Add<MyGCPrinter>
@@ -920,85 +918,74 @@ map for the entire module, and may acces
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Target/TargetMachine.h"
- void MyGCPrinter::beginAssembly(std::ostream &OS, AsmPrinter &AP,
- const TargetAsmInfo &TAI) {
+ void MyGCPrinter::beginAssembly(AsmPrinter &AP) {
// Nothing to do.
}
- void MyGCPrinter::finishAssembly(std::ostream &OS, AsmPrinter &AP,
- const TargetAsmInfo &TAI) {
- // Set up for emitting addresses.
- const char *AddressDirective;
- int AddressAlignLog;
- if (AP.TM.getDataLayout()->getPointerSize() == sizeof(int32_t)) {
- AddressDirective = TAI.getData32bitsDirective();
- AddressAlignLog = 2;
- } else {
- AddressDirective = TAI.getData64bitsDirective();
- AddressAlignLog = 3;
- }
+ void MyGCPrinter::finishAssembly(AsmPrinter &AP) {
+ MCStreamer &OS = AP.OutStreamer;
+ unsigned IntPtrSize = AP.TM.getDataLayout()->getPointerSize();
// Put this in the data section.
- AP.SwitchToDataSection(TAI.getDataSection());
+ OS.SwitchSection(AP.getObjFileLowering().getDataSection());
// For each function...
for (iterator FI = begin(), FE = end(); FI != FE; ++FI) {
GCFunctionInfo &MD = **FI;
- // Emit this data structure:
+ // A compact GC layout. Emit this data structure:
//
// struct {
// int32_t PointCount;
- // struct {
- // void *SafePointAddress;
- // int32_t LiveCount;
- // int32_t LiveOffsets[LiveCount];
- // } Points[PointCount];
+ // void *SafePointAddress[PointCount];
+ // int32_t StackFrameSize; // in words
+ // int32_t StackArity;
+ // int32_t LiveCount;
+ // int32_t LiveOffsets[LiveCount];
// } __gcmap_<FUNCTIONNAME>;
// Align to address width.
- AP.EmitAlignment(AddressAlignLog);
-
- // Emit the symbol by which the stack map entry can be found.
- std::string Symbol;
- Symbol += TAI.getGlobalPrefix();
- Symbol += "__gcmap_";
- Symbol += MD.getFunction().getName();
- if (const char *GlobalDirective = TAI.getGlobalDirective())
- OS << GlobalDirective << Symbol << "\n";
- OS << TAI.getGlobalPrefix() << Symbol << ":\n";
+ AP.EmitAlignment(IntPtrSize == 4 ? 2 : 3);
// Emit PointCount.
+ OS.AddComment("safe point count");
AP.EmitInt32(MD.size());
- AP.EOL("safe point count");
// And each safe point...
for (GCFunctionInfo::iterator PI = MD.begin(),
- PE = MD.end(); PI != PE; ++PI) {
- // Align to address width.
- AP.EmitAlignment(AddressAlignLog);
-
+ PE = MD.end(); PI != PE; ++PI) {
// Emit the address of the safe point.
- OS << AddressDirective
- << TAI.getPrivateGlobalPrefix() << "label" << PI->Num;
- AP.EOL("safe point address");
-
- // Emit the stack frame size.
- AP.EmitInt32(MD.getFrameSize());
- AP.EOL("stack frame size");
-
- // Emit the number of live roots in the function.
- AP.EmitInt32(MD.live_size(PI));
- AP.EOL("live root count");
-
- // And for each live root...
- for (GCFunctionInfo::live_iterator LI = MD.live_begin(PI),
- LE = MD.live_end(PI);
- LI != LE; ++LI) {
- // Print its offset within the stack frame.
- AP.EmitInt32(LI->StackOffset);
- AP.EOL("stack offset");
- }
+ OS.AddComment("safe point address");
+ MCSymbol *Label = PI->Label;
+ AP.EmitLabelPlusOffset(Label/*Hi*/, 0/*Offset*/, 4/*Size*/);
+ }
+
+ // Stack information never change in safe points! Only print info from the
+ // first call-site.
+ GCFunctionInfo::iterator PI = MD.begin();
+
+ // Emit the stack frame size.
+ OS.AddComment("stack frame size (in words)");
+ AP.EmitInt32(MD.getFrameSize() / IntPtrSize);
+
+ // Emit stack arity, i.e. the number of stacked arguments.
+ unsigned RegisteredArgs = IntPtrSize == 4 ? 5 : 6;
+ unsigned StackArity = MD.getFunction().arg_size() > RegisteredArgs ?
+ MD.getFunction().arg_size() - RegisteredArgs : 0;
+ OS.AddComment("stack arity");
+ AP.EmitInt32(StackArity);
+
+ // Emit the number of live roots in the function.
+ OS.AddComment("live root count");
+ AP.EmitInt32(MD.live_size(PI));
+
+ // And for each live root...
+ for (GCFunctionInfo::live_iterator LI = MD.live_begin(PI),
+ LE = MD.live_end(PI);
+ LI != LE; ++LI) {
+ // Emit live root's offset within the stack frame.
+ OS.AddComment("stack index (offset / wordsize)");
+ AP.EmitInt32(LI->StackOffset);
}
}
}
@@ -1026,4 +1013,3 @@ programming.
[Henderson2002] `Accurate Garbage Collection in an Uncooperative Environment
<http://citeseer.ist.psu.edu/henderson02accurate.html>`__
-
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