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Diffstat (limited to 'llvm/examples/TracingBrainF/BrainFTraceRecorder.cpp')
| -rw-r--r-- | llvm/examples/TracingBrainF/BrainFTraceRecorder.cpp | 155 |
1 files changed, 0 insertions, 155 deletions
diff --git a/llvm/examples/TracingBrainF/BrainFTraceRecorder.cpp b/llvm/examples/TracingBrainF/BrainFTraceRecorder.cpp deleted file mode 100644 index cd8babd1991..00000000000 --- a/llvm/examples/TracingBrainF/BrainFTraceRecorder.cpp +++ /dev/null @@ -1,155 +0,0 @@ -//===-- BrainFTraceRecorder.cpp - BrainF trace recorder ------------------==// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===--------------------------------------------------------------------===// -// -// This class observes the execution trace of the interpreter, identifying -// hot traces and eventually compiling them to native code. -// -// The operation of the recorder can be divided into four parts: -// 1) Interation Counting - To identify hot traces, we track the execution -// counts of all loop headers ('[' instructions). We use a fixed-size -// array of counters for this, since lack of precision does not affect -// correctness. -// -// 2) Trace Buffering - Once a header has passed a hotness threshold, we -// begin buffering the execution trace beginning from that header the -// next time it is executed. This buffer is of a fixed length, though -// that choice can be tuned for performance. If the end of the buffer -// is reached without execution returning to the header, we throw out -// the trace. -// -// 3) Trace Commit - If the buffered trace returns to the header before -// the buffer limit is reached, that trace is commited to form a trace -// tree. This tree aggregates all execution traces that have been -// observed originating from the header since it passed the hotness -// threshold. The buffer is then cleared to allow a new trace to be -// recorded. -// -// 4) Trace Compilation - Once a secondary hotness threshold is reached, -// trace recording is terminated and the set of observed traces encoded -// in the trace tree are compiled to native code, and a function pointer -// to that trace is installed into the bytecode array in place of one of -// the normal opcode functions. Details of this compilation are in -// BrainFCodeGen.cpp -//===--------------------------------------------------------------------===// - -#include "BrainF.h" -#include "BrainFVM.h" -#include "llvm/Support/raw_ostream.h" - -#define ITERATION_BUF_SIZE 1024 -#define TRACE_BUF_SIZE 256 -#define TRACE_THRESHOLD 50 -#define COMPILE_THRESHOLD 200 - -void BrainFTraceRecorder::BrainFTraceNode::dump(unsigned lvl) { - for (unsigned i = 0; i < lvl; ++i) - outs() << '.'; - outs() << opcode << " : " << pc << "\n"; - if (left && left != (BrainFTraceNode*)~0ULL) left->dump(lvl+1); - if (right && right != (BrainFTraceNode*)~0ULL) right->dump(lvl+1); -} - -BrainFTraceRecorder::BrainFTraceRecorder() - : prev_opcode('+'), iteration_count(new uint8_t[ITERATION_BUF_SIZE]), - trace_begin(new std::pair<uint8_t, size_t>[TRACE_BUF_SIZE]), - trace_end(trace_begin + TRACE_BUF_SIZE), - trace_tail(trace_begin), - module(new Module("BrainF", getGlobalContext())) { - memset(iteration_count, 0, ITERATION_BUF_SIZE); - memset(trace_begin, 0, sizeof(std::pair<uint8_t, size_t>) * TRACE_BUF_SIZE); - - initialize_module(); -} - -BrainFTraceRecorder::~BrainFTraceRecorder() { - delete[] iteration_count; - delete[] trace_begin; - delete FPM; - delete EE; -} - -void BrainFTraceRecorder::commit() { - BrainFTraceNode *&Head = trace_map[trace_begin->second]; - if (!Head) - Head = new BrainFTraceNode(trace_begin->first, trace_begin->second); - - BrainFTraceNode *Parent = Head; - std::pair<uint8_t, size_t> *trace_iter = trace_begin+1; - while (trace_iter != trace_tail) { - BrainFTraceNode *Child = 0; - - if (trace_iter->second == Parent->pc+1) { - if (Parent->left) Child = Parent->left; - else Child = Parent->left = - new BrainFTraceNode(trace_iter->first, trace_iter->second); - } else { - if (Parent->right) Child = Parent->right; - else Child = Parent->right = - new BrainFTraceNode(trace_iter->first, trace_iter->second); - } - - Parent = Child; - ++trace_iter; - } - - if (Parent->pc+1 == Head->pc) - Parent->left = (BrainFTraceNode*)~0ULL; - else - Parent->right = (BrainFTraceNode*)~0ULL; -} - -void BrainFTraceRecorder::record_simple(size_t pc, uint8_t opcode) { - if (executed) { - executed = false; - trace_tail = trace_begin; - } - - if (trace_tail != trace_begin) { - if (trace_tail == trace_end) { - trace_tail = trace_begin; - } else { - trace_tail->first = opcode; - trace_tail->second = pc; - ++trace_tail; - } - } - prev_opcode = opcode; -} - -void BrainFTraceRecorder::record(size_t pc, uint8_t opcode) { - if (executed) { - executed = false; - trace_tail = trace_begin; - } - - if (trace_tail != trace_begin) { - if (pc == trace_begin->second) { - commit(); - trace_tail = trace_begin; - } else if (trace_tail == trace_end) { - trace_tail = trace_begin; - } else { - trace_tail->first = opcode; - trace_tail->second = pc; - ++trace_tail; - } - } else if (opcode == '[' && prev_opcode == ']'){ - size_t hash = pc % ITERATION_BUF_SIZE; - if (iteration_count[hash] == 255) iteration_count[hash] = 254; - if (++iteration_count[hash] > COMPILE_THRESHOLD && trace_map.count(pc)) { - compile(trace_map[pc]); - } else if (++iteration_count[hash] > TRACE_THRESHOLD) { - trace_tail->first = opcode; - trace_tail->second = pc; - ++trace_tail; - } - } - - prev_opcode = opcode; -}
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