[StackSafety] Add info into function summary

Summary:
This patch adds optional field into function summary,
implements asm and bitcode serialization. YAML
serialization is omitted and can be added later if
needed.

This patch includes this information into summary only
if module contains at least one sanitize_memtag function.
In a near future MTE is the user of the analysis.
Later if needed we can provede more direct control
on when information is included into summary.

Reviewers: eugenis

Subscribers: hiraditya, steven_wu, dexonsmith, arphaman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80908

1 files changed, 23 insertions, 0 deletions

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 992cdfc..653d7f9 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -3576,6 +3576,29 @@ static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
                      FS->type_test_assume_const_vcalls());
   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
                      FS->type_checked_load_const_vcalls());
+
+  auto WriteRange = [&](ConstantRange Range) {
+    Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
+    assert(Range.getLower().getNumWords() == 1);
+    assert(Range.getUpper().getNumWords() == 1);
+    emitSignedInt64(Record, *Range.getLower().getRawData());
+    emitSignedInt64(Record, *Range.getUpper().getRawData());
+  };
+
+  if (!FS->paramAccesses().empty()) {
+    Record.clear();
+    for (auto &Arg : FS->paramAccesses()) {
+      Record.push_back(Arg.ParamNo);
+      WriteRange(Arg.Use);
+      Record.push_back(Arg.Calls.size());
+      for (auto &Call : Arg.Calls) {
+        Record.push_back(Call.ParamNo);
+        Record.push_back(Call.Callee);
+        WriteRange(Call.Offsets);
+      }
+    }
+    Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
+  }
 }
 
 /// Collect type IDs from type tests used by function.