[llvm] [llvm-remarkutil] Add an instruction-mix tool (PR #140598)

[Tobias Stadler via llvm-commits]

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@@ -0,0 +1,150 @@
+//===- RemarkInstructionMix.cpp -------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Generic tool to extract instruction mix from asm-printer remarks.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RemarkUtilHelpers.h"
+#include "RemarkUtilRegistry.h"
+
+#include "llvm/Support/Format.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/Regex.h"
+
+#include <cmath>
+#include <numeric>
+
+using namespace llvm;
+using namespace remarks;
+using namespace llvm::remarkutil;
+
+namespace instructionmix {
+
+static cl::SubCommand
+    InstructionMix("instruction-mix",
+                   "Instruction Mix (requires asm-printer remarks)");
+
+static cl::opt<std::string>
+    FunctionFilter("filter", cl::sub(InstructionMix), cl::ValueOptional,
+                   cl::desc("Optional function name to filter collection by"));
+
+static cl::opt<std::string>
+    FunctionFilterRE("rfilter", cl::sub(InstructionMix), cl::ValueOptional,
+                     cl::desc("Optional function name to filter collection by "
+                              "(accepts regular expressions)"));
+
+enum ReportStyleOptions { human_output, csv_output };
+static cl::opt<ReportStyleOptions> ReportStyle(
+    "report_style", cl::sub(InstructionMix),
+    cl::init(ReportStyleOptions::human_output),
+    cl::desc("Choose the report output format:"),
+    cl::values(clEnumValN(human_output, "human", "Human-readable format"),
+               clEnumValN(csv_output, "csv", "CSV format")));
+
+INPUT_FORMAT_COMMAND_LINE_OPTIONS(InstructionMix)
+INPUT_OUTPUT_COMMAND_LINE_OPTIONS(InstructionMix)
+
+static Expected<FilterMatcher> getRemarkFilter() {
+  if (FunctionFilter.getNumOccurrences())
+    return FilterMatcher::createExact(FunctionFilter);
+  if (FunctionFilterRE.getNumOccurrences())
+    return FilterMatcher::createRE(FunctionFilterRE);
+  return FilterMatcher::createAny();
+}
+
+static Error tryInstructionMix() {
+  auto MaybeOF =
+      getOutputFileWithFlags(OutputFileName, sys::fs::OF_TextWithCRLF);
+  if (!MaybeOF)
+    return MaybeOF.takeError();
+
+  auto OF = std::move(*MaybeOF);
+  auto MaybeBuf = getInputMemoryBuffer(InputFileName);
+  if (!MaybeBuf)
+    return MaybeBuf.takeError();
+  auto MaybeParser = createRemarkParser(InputFormat, (*MaybeBuf)->getBuffer());
+  if (!MaybeParser)
+    return MaybeParser.takeError();
+
+  Expected<FilterMatcher> Filter = getRemarkFilter();
+  if (!Filter)
+    return Filter.takeError();
+
+  // Collect the histogram of instruction counts.
+  std::unordered_map<std::string, unsigned> Histogram;
+  auto &Parser = **MaybeParser;
+  auto MaybeRemark = Parser.next();
+  for (; MaybeRemark; MaybeRemark = Parser.next()) {
+    auto &Remark = **MaybeRemark;
+    if (Remark.RemarkName != "InstructionMix")
+      continue;
+    if (!Filter->match(Remark.FunctionName))
+      continue;
+    for (auto &Arg : Remark.Args) {
+      StringRef Key = Arg.Key;
+      if (!Key.consume_front("INST_"))
+        continue;
+      unsigned Val = 0;
+      bool ParseError = Arg.Val.getAsInteger(10, Val);
+      assert(!ParseError);
+      (void)ParseError;
+      Histogram[std::string(Key)] += Val;
+    }
+  }
+
+  // Sort it.
+  using MixEntry = std::pair<std::string, unsigned>;
+  llvm::SmallVector<MixEntry> Mix(Histogram.begin(), Histogram.end());
+  std::sort(Mix.begin(), Mix.end(), [](const auto &LHS, const auto &RHS) {
+    return LHS.second > RHS.second;
+  });
+
+  // Print the results.
+  switch (ReportStyle) {
+  case human_output: {
+    formatted_raw_ostream FOS(OF->os());
+    size_t MaxMnemonic =
+        std::accumulate(Mix.begin(), Mix.end(), StringRef("Instruction").size(),
+                        [](size_t MaxMnemonic, const MixEntry &Elt) {
+                          return std::max(MaxMnemonic, Elt.first.length());
+                        });
+    unsigned MaxValue = std::accumulate(
+        Mix.begin(), Mix.end(), 0, [](unsigned MaxValue, const MixEntry &Elt) {
+          return std::max(MaxValue, Elt.second);
+        });
+    unsigned ValueWidth = std::log10(MaxValue) + 1;
----------------
tobias-stadler wrote:

I think If all entries are filtered out and thus MaxValue == 0, log10 returns -inf. I believe converting that to unsigned is UB.

https://github.com/llvm/llvm-project/pull/140598