[PATCH] D119892: [lld-macho][nfc] Factor out callgraph parsing code

[Jez Ng via Phabricator via llvm-commits]

int3 created this revision.
int3 added reviewers: lld-macho, lgrey.
Herald added a project: lld-macho.
int3 requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

`parseSections()` is a getting a bit large unwieldy, let's factor out
logic where we can.

Other minor changes in this diff:

- `"__cg_profile"` is now a global constexpr
- We now use `checkError()` instead of `fatal()`-ing without handling the Error
- Check for `callGraphProfileSort` before checking the section name, since the boolean comparison is likely cheaper


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D119892

Files:
  lld/MachO/InputFiles.cpp
  lld/MachO/InputSection.h


Index: lld/MachO/InputSection.h
===================================================================
--- lld/MachO/InputSection.h
+++ lld/MachO/InputSection.h
@@ -283,6 +283,7 @@
 constexpr const char bitcodeBundle[] = "__bundle";
 constexpr const char cString[] = "__cstring";
 constexpr const char cfString[] = "__cfstring";
+constexpr const char cgProfile[] = "__cg_profile";
 constexpr const char codeSignature[] = "__code_signature";
 constexpr const char common[] = "__common";
 constexpr const char compactUnwind[] = "__compact_unwind";
Index: lld/MachO/InputFiles.cpp
===================================================================
--- lld/MachO/InputFiles.cpp
+++ lld/MachO/InputFiles.cpp
@@ -262,6 +262,28 @@
   return {};
 }
 
+static Error parseCallGraph(ArrayRef<uint8_t> data,
+                            std::vector<CallGraphEntry> &callGraph) {
+  TimeTraceScope timeScope("Parsing call graph section");
+  BinaryStreamReader reader(data, support::little);
+  while (!reader.empty()) {
+    uint32_t fromIndex, toIndex;
+    uint64_t count;
+    if (Error err = reader.readInteger(fromIndex))
+      return err;
+    if (Error err = reader.readInteger(toIndex))
+      return err;
+    if (Error err = reader.readInteger(count))
+      return err;
+    callGraph.emplace_back();
+    CallGraphEntry &entry = callGraph.back();
+    entry.fromIndex = fromIndex;
+    entry.toIndex = toIndex;
+    entry.count = count;
+  }
+  return Error::success();
+}
+
 // Parse the sequence of sections within a single LC_SEGMENT(_64).
 // Split each section into subsections.
 template <class SectionHeader>
@@ -320,25 +342,8 @@
       if (name == section_names::compactUnwind)
         compactUnwindSection = sections.back();
     } else if (segname == segment_names::llvm) {
-      if (name == "__cg_profile" && config->callGraphProfileSort) {
-        TimeTraceScope timeScope("Parsing call graph section");
-        BinaryStreamReader reader(data, support::little);
-        while (!reader.empty()) {
-          uint32_t fromIndex, toIndex;
-          uint64_t count;
-          if (Error err = reader.readInteger(fromIndex))
-            fatal(toString(this) + ": Expected 32-bit integer");
-          if (Error err = reader.readInteger(toIndex))
-            fatal(toString(this) + ": Expected 32-bit integer");
-          if (Error err = reader.readInteger(count))
-            fatal(toString(this) + ": Expected 64-bit integer");
-          callGraph.emplace_back();
-          CallGraphEntry &entry = callGraph.back();
-          entry.fromIndex = fromIndex;
-          entry.toIndex = toIndex;
-          entry.count = count;
-        }
-      }
+      if (config->callGraphProfileSort && name == section_names::cgProfile)
+        checkError(parseCallGraph(data, callGraph));
       // ld64 does not appear to emit contents from sections within the __LLVM
       // segment. Symbols within those sections point to bitcode metadata
       // instead of actual symbols. Global symbols within those sections could


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