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e0d9c58443
Add the commandline options -fprofile-instr-generate[=filename] and -profile-instr-use=filename -fprofile-instr-generate -- Add instrumentation on branches, switches, and function entry; uses LLVM's InstrProf pass. -- Link to profile runtime that writes instrumentation counters to a file. -fprofile-instr-use -- Read profile data from a file and apply branch weights to branches and switches, and annotate functions with entrycount in LLVM IR. -- Functions with low or high entrycount are marked with 'cold' or 'inlinehint'. The only statement type without PGO yet is "try-finally". A new pragma, `pragma(LDC_profile_instr, [ true | false ])`, is added to selectively disable/enable instrumentation of functions (granularity = whole functions). The runtime library ldc-profile-rt is a copy of LLVM compiler-rt lib/profile. It has to be exactly in-sync with the LLVM version, and thus we need a copy for each PGO-supported LLVM (>=3.7). import ldc.profile for a D interface to ldc-profile-rt (for example to reset execution counts after a program startup phase). The instrumentation data is mainly passed on to LLVM: function-entry counts and branch counts/probabilities. LDC marks functions as hot when "execution count is 30% of the maximum function execution count", and marks functions as cold if their count is 1% of maximum function execution count. The source of LLVM's llvm-profdata tool is hereby included in LDCs repository (different source for each LLVM version), and the binary is included in the install bin folder. The executable is named "ldc-profdata" to avoid clashing with llvm-profdata on the same machine. This is needed because profdata executable has to be in-sync with the LLVM version used to build LDC. Maintenance burden: for trunk LLVM, we have to keep ldc-profile-rt and llvm-profdata in sync. There is no diff with upstream; but because of active development there are the occasional API changes.
54 lines
1.5 KiB
D
54 lines
1.5 KiB
D
//===-- gen/pragma.d - LDC-specific pragma handling ---------------*- D -*-===//
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//
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// LDC – the LLVM D compiler
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//
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// This file is distributed under the BSD-style LDC license. See the LICENSE
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// file for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// D bindings for pragma.h/.cpp
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//
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//===----------------------------------------------------------------------===//
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module gen.dpragma;
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import ddmd.attrib;
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import ddmd.dscope;
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import ddmd.dsymbol;
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import ddmd.expression;
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import ddmd.func;
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extern (C++) enum LDCPragma : int {
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LLVMnone = 0, // Not an LDC pragma.
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LLVMignore, // Pragma has already been processed in DtoGetPragma, ignore.
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LLVMintrinsic,
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LLVMglobal_crt_ctor,
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LLVMglobal_crt_dtor,
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LLVMno_typeinfo,
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LLVMalloca,
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LLVMva_start,
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LLVMva_copy,
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LLVMva_end,
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LLVMva_arg,
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LLVMinline_asm,
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LLVMinline_ir,
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LLVMfence,
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LLVMatomic_store,
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LLVMatomic_load,
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LLVMatomic_cmp_xchg,
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LLVMatomic_rmw,
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LLVMbitop_bt,
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LLVMbitop_btc,
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LLVMbitop_btr,
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LLVMbitop_bts,
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LLVMbitop_vld,
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LLVMbitop_vst,
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LLVMextern_weak
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};
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extern (C++) LDCPragma DtoGetPragma(Scope* sc, PragmaDeclaration decl, ref const(char)* arg1str);
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extern (C++) void DtoCheckPragma(PragmaDeclaration decl, Dsymbol sym, LDCPragma llvm_internal, const char* arg1str);
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extern (C++) bool DtoCheckProfileInstrPragma(Expression arg, ref bool value);
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extern (C++) bool DtoIsIntrinsic(FuncDeclaration fd);
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extern (C++) bool DtoIsVaIntrinsic(FuncDeclaration fd);
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