[llvm-commits] GC patches again
Chris Lattner
clattner at apple.com
Thu Sep 27 11:58:08 PDT 2007
> //===-- gc-0-docs.patch (+1170 -241) --------------------------===//
>
> runtime/GC/SemiSpace/README.txt (+5)
> docs/llvm.css (+1 -1)
> docs/Lexicon.html (+76 -3)
> docs/GarbageCollection.html (+1088 -237)
>
> GarbageCollection.html is expanded to encompass the new
> capabilities. This is a major rewrite and is easier to read en toto
> rather than patchwise:
>
> http://homepage.mac.com/malichus/GarbageCollection.html
>
> This patch is independent.
Looks good, please apply.
> //===-- gc-1-registry.patch (+300) ----------------------------===//
>
> include/llvm/Support/Registry.h (+243)
> include/llvm/CodeGen/Collectors.h (+36)
> lib/CodeGen/Collectors.cpp (+21)
>
> My previous Registry.h header, as well as Collectors.h, which is the
> registry for dynamically-loaded garbage collectors.
>
> This patch is independent.
Very nice, plz apply.
> //===-- gc-2-metadata.patch (+383) ----------------------------===//
>
> include/llvm/CodeGen/CollectorMetadata.h (+198)
> lib/CodeGen/CollectorMetadata.cpp (+185)
>
> CollectorMetadata is the data structure populated by back-ends
> during code-generation.
>
> This patch is independent.
In CollectorMetadata.h, you can drop these two #includes:
+#include <ostream>
+#include <vector>
they are pulled in from Pass.h. Please reorder the remaining
#includes as:
+#include "llvm/Pass.h"
+#include "llvm/ADT/DenseMap.h"
So the ADT one comes later than the core llvm one.
+namespace llvm {
+
+ class FunctionPass;
+ class Constant;
You probably don't need these.
In the .cpp file, I'm not sure why you need the Deleter class. It
seems like the CollectorModuleMetadata pass should manage its own
lifetime (freeing itself on releaseMemory). This will require all
the machinefunctionpasses to preserve CollectorModuleMetadata
though. Does this make sense?
Will read the rest later,
-Chris
>
> //===-- gc-3-collector.patch (+531) ---------------------------===//
>
> include/llvm/CodeGen/Collector.h (+134)
> lib/CodeGen/Collector.cpp (+359)
> lib/CodeGen/README.txt (+38)
>
> Collector is the base class for garbage collector code generators.
> This version enhances the previous patch to add root initialization
> as discussed here:
>
> http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-
> Mon-20070910/053455.html
>
> Collector gives its subclasses control over generic algorithms:
>
> unsigned NeededSafePoints; //< Bitmask of required safe points.
> bool CustomReadBarriers; //< Default is to insert loads.
> bool CustomWriteBarriers; //< Default is to insert stores.
> bool CustomRoots; //< Default is to pass through to
> backend.
> bool InitRoots; //< If set, roots are nulled during
> lowering.
>
> It also has callbacks which collectors can hook:
>
> /// If any of the actions are set to Custom, this is expected to
> /// be overriden to create a transform to lower those actions to
> /// LLVM IR.
> virtual Pass *createCustomLoweringPass() const;
>
> /// beginAssembly/finishAssembly - Emit module metadata as
> /// assembly code.
> virtual void beginAssembly(Module &M, std::ostream &OS,
> AsmPrinter &AP,
> const TargetAsmInfo &TAI) const;
> virtual void finishAssembly(Module &M,
> CollectorModuleMetadata &CMM,
> std::ostream &OS, AsmPrinter &AP,
> const TargetAsmInfo &TAI) const;
>
> Various other independent algorithms could be implemented, but were
> not necessary for the initial two collectors. Some examples are
> listed here:
>
> http://lists.cs.uiuc.edu/pipermail/llvmdev/2007-August/010500.html
>
> This patch depends on gc-2-metadata.
>
>
> //===-- gc-4-integration.patch (+116 -17) ---------------------===//
>
> include/llvm/CodeGen/LinkAllCodegenComponents.h (+4)
> include/llvm/CodeGen/SelectionDAGISel.h (+3 -1)
> include/llvm/CodeGen/AsmPrinter.h (+4)
> tools/llc/llc.cpp (+13)
> lib/CodeGen/LLVMTargetMachine.cpp (+28 -4)
> lib/CodeGen/AsmPrinter.cpp (+15)
> lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (+41 -9)
> lib/Target/ARM/ARMAsmPrinter.cpp (+1)
> lib/Target/X86/X86AsmPrinter.h (+1 -1)
> lib/Target/CBackend/CBackend.cpp (+3 -1)
> lib/Target/MSIL/MSILWriter.cpp (+3 -1)
>
> In this patch, Collector winds its tendrils throughout the compiler.
> Overhead should be minimal when disabled.
>
> I would particularly appreciate any feedback on this interface.
> The primary item of concern to me is that I exposed the desired
> collector to the compiler using a global. I have not decided on a
> better approach. In the meantime, it works and is simple.
>
> Less concretely, I am not convinced that Collector is well-factored
> in its interaction with TargetMachine et al. Collector and
> TargetMachine have no way of sniffing their respective capabilities
> and requirements. So llc -march=c -gc=ocaml with silently do the
> wrong thing; likewise the JIT, object writers, and MSIL backend.
>
> Finally, the -gc option is mandatory if collector intrinsics are
> used. This is somewhat sensible since there is no default collector
> runtime (excluding the MSIL target), but I would rather stuff any
> necessary information inside the LLVM representation somehow so that
> the .bc/.ll remain self-contained.
>
> This patch depends on gc-1-registry and gc-3-collector.
>
>
> //===-- gc-5-shadowstack.patch (+493 -371) --------------------===//
>
> test/CodeGen/Generic/GC/alloc_loop.ll (+1 -1)
> test/CodeGen/Generic/GC/lower_gcroot.ll (+1 -1)
> test/CodeGen/Generic/GC/redundant_init.ll (+17)
> include/llvm/LinkAllPasses.h (-1)
> include/llvm/Transforms/Scalar.h (-7)
> runtime/GC/SemiSpace/semispace.c (+15 -13)
> lib/CodeGen/ShadowStackCollector.cpp (+459)
> lib/Transforms/Scalar/LowerGC.cpp (-348)
>
> With this patch, the LowerGC transformation becomes the
> ShadowStackCollector, which additionally has reduced overhead with
> no sacrifice in portability.
>
> This patch depends on gc-4-integration.
>
>
> Considering a function @fun with 8 loop-local roots,
> ShadowStackCollector introduces the following overhead
> (x86):
>
> ; shadowstack prologue
> movl L_llvm_gc_root_chain$non_lazy_ptr, %eax
> movl (%eax), %ecx
> movl $___gc_fun, 20(%esp)
> movl $0, 24(%esp)
> movl $0, 28(%esp)
> movl $0, 32(%esp)
> movl $0, 36(%esp)
> movl $0, 40(%esp)
> movl $0, 44(%esp)
> movl $0, 48(%esp)
> movl $0, 52(%esp)
> movl %ecx, 16(%esp)
> leal 16(%esp), %ecx
> movl %ecx, (%eax)
>
> ; shadowstack loop overhead
> (none)
>
> ; shadowstack epilogue
> movl 48(%esp), %edx
> movl %edx, (%ecx)
>
> ; shadowstack metadata
> .align 3
> ___gc_fun: # __gc_fun
> .long 8
> .space 4
>
> In comparison to LowerGC:
>
> ; lowergc prologue
> movl L_llvm_gc_root_chain$non_lazy_ptr, %eax
> movl (%eax), %ecx
> movl %ecx, 48(%esp)
> movl $8, 52(%esp)
> movl $0, 60(%esp)
> movl $0, 56(%esp)
> movl $0, 68(%esp)
> movl $0, 64(%esp)
> movl $0, 76(%esp)
> movl $0, 72(%esp)
> movl $0, 84(%esp)
> movl $0, 80(%esp)
> movl $0, 92(%esp)
> movl $0, 88(%esp)
> movl $0, 100(%esp)
> movl $0, 96(%esp)
> movl $0, 108(%esp)
> movl $0, 104(%esp)
> movl $0, 116(%esp)
> movl $0, 112(%esp)
>
> ; lowergc loop overhead
> leal 44(%esp), %eax
> movl %eax, 56(%esp)
> leal 40(%esp), %eax
> movl %eax, 64(%esp)
> leal 36(%esp), %eax
> movl %eax, 72(%esp)
> leal 32(%esp), %eax
> movl %eax, 80(%esp)
> leal 28(%esp), %eax
> movl %eax, 88(%esp)
> leal 24(%esp), %eax
> movl %eax, 96(%esp)
> leal 20(%esp), %eax
> movl %eax, 104(%esp)
> leal 16(%esp), %eax
> movl %eax, 112(%esp)
>
> ; lowergc epilogue
> movl 48(%esp), %edx
> movl %edx, (%ecx)
>
> ; lowergc metadata
> (none)
>
>
> //===-- gc-6-ocaml-collector.patch (+219) ---------------------===//
>
> test/CodeGen/Generic/GC/simple_ocaml.ll (+42)
> test/CodeGen/Generic/GC/frame_size.ll (+13)
> lib/CodeGen/OcamlCollector.cpp (+164)
>
> The new OcamlCollector emits the Ocaml frametable data structure and
> related symbols.
>
> This patch depends on gc-4-integration.
>
>
> $ llvm-as -o simple_ocaml.bc simple_ocaml.ll
> $ llc -gc=ocaml -asm-verbose -o - simple_ocaml.bc
> .text
> _camlSimple_ocaml__code_begin:
> .data
> _camlSimple_ocaml__data_begin:
>
>
> .text
> .align 4,0x90
> .globl _fun
> _fun:
> subl $12, %esp
> movl $0, 4(%esp)
> movl $0, 8(%esp)
> movl 16(%esp), %eax
> movl %eax, 4(%esp)
> LBB1_1: # bb.loop
> movl 4(%esp), %eax
> movl 4(%eax), %eax
> testl %eax, %eax
> je LBB1_1 # bb.loop
> LBB1_2: # bb.end
> movl $8, (%esp)
> call L_malloc$stub
>
> Llabel1:
> movl %eax, 8(%esp)
> movl 4(%esp), %ecx
> movl %ecx, 4(%ecx)
> addl $12, %esp
> ret
> .section __IMPORT,__jump_table,symbol_stubs,self_modifying_code
> +pure_instructions,5
> L_malloc$stub:
> .indirect_symbol _malloc
> hlt ; hlt ; hlt ; hlt ; hlt
>
> .subsections_via_symbols
>
> .text
> _camlSimple_ocaml__code_end:
> .data
> _camlSimple_ocaml__data_end:
> .long 0
> _camlSimple_ocaml__frametable:
> # live roots for fun
> .long Llabel1 # call return address
> .short 0xc # stack frame size
> .short 0x2 # live root count
> .word 4 # stack offset
> .word 8 # stack offset
> .align 2
>
>
> //===-- housekeeping.patch (+16) ------------------------------===//
>
> Xcode/LLVM.xcodeproj/project.pbxproj (+16)
>
> Just updating the Xcode project.
>
>
> <gc.5.zip>
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