[llvm-branch-commits] [llvm] [MC][NFC] Statically allocate storage for decoded pseudo probes and function records (PR #102789)

[Amir Ayupov via llvm-branch-commits]

https://github.com/aaupov updated https://github.com/llvm/llvm-project/pull/102789

>From ddcbb593f72ca47acaa82f9c14a7fd2c4e30903b Mon Sep 17 00:00:00 2001
From: Amir Ayupov <aaupov at fb.com>
Date: Tue, 13 Aug 2024 03:51:31 -0700
Subject: [PATCH] Pass CurChildIndex by value

Created using spr 1.3.4
---
 llvm/include/llvm/MC/MCPseudoProbe.h |  6 ++++--
 llvm/lib/MC/MCPseudoProbe.cpp        | 26 +++++++++++---------------
 2 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/llvm/include/llvm/MC/MCPseudoProbe.h b/llvm/include/llvm/MC/MCPseudoProbe.h
index a46188e565c7e8..32d7a4e9129eca 100644
--- a/llvm/include/llvm/MC/MCPseudoProbe.h
+++ b/llvm/include/llvm/MC/MCPseudoProbe.h
@@ -474,11 +474,13 @@ class MCPseudoProbeDecoder {
   }
 
 private:
+  // Recursively parse an inlining tree encoded in pseudo_probe section. Returns
+  // whether the the top-level node should be skipped.
   template <bool IsTopLevelFunc>
-  void buildAddress2ProbeMap(MCDecodedPseudoProbeInlineTree *Cur,
+  bool buildAddress2ProbeMap(MCDecodedPseudoProbeInlineTree *Cur,
                              uint64_t &LastAddr, const Uint64Set &GuildFilter,
                              const Uint64Map &FuncStartAddrs,
-                             uint32_t &CurChild);
+                             const uint32_t CurChildIndex);
 };
 
 } // end namespace llvm
diff --git a/llvm/lib/MC/MCPseudoProbe.cpp b/llvm/lib/MC/MCPseudoProbe.cpp
index c4c2dfcec40564..e6f6e797b4ee71 100644
--- a/llvm/lib/MC/MCPseudoProbe.cpp
+++ b/llvm/lib/MC/MCPseudoProbe.cpp
@@ -420,17 +420,17 @@ bool MCPseudoProbeDecoder::buildGUID2FuncDescMap(const uint8_t *Start,
 }
 
 template <bool IsTopLevelFunc>
-void MCPseudoProbeDecoder::buildAddress2ProbeMap(
+bool MCPseudoProbeDecoder::buildAddress2ProbeMap(
     MCDecodedPseudoProbeInlineTree *Cur, uint64_t &LastAddr,
     const Uint64Set &GuidFilter, const Uint64Map &FuncStartAddrs,
-    uint32_t &CurChild) {
+    const uint32_t CurChildIndex) {
   // The pseudo_probe section encodes an inline forest and each tree has a
   // format defined in MCPseudoProbe.h
 
   uint32_t Index = 0;
   if (IsTopLevelFunc) {
     // Use a sequential id for top level inliner.
-    Index = CurChild;
+    Index = CurChildIndex;
   } else {
     // Read inline site for inlinees
     Index = cantFail(errorOrToExpected(readUnsignedNumber<uint32_t>()));
@@ -446,19 +446,14 @@ void MCPseudoProbeDecoder::buildAddress2ProbeMap(
   // If the incoming node is null, all its children nodes should be disgarded.
   if (Cur) {
     // Switch/add to a new tree node(inlinee)
-    Cur->Children[CurChild] = MCDecodedPseudoProbeInlineTree(Guid, Index, Cur);
-    Cur = &Cur->Children[CurChild];
+    Cur->Children[CurChildIndex] =
+        MCDecodedPseudoProbeInlineTree(Guid, Index, Cur);
+    Cur = &Cur->Children[CurChildIndex];
     if (IsTopLevelFunc && !EncodingIsAddrBased) {
       if (auto V = FuncStartAddrs.lookup(Guid))
         LastAddr = V;
     }
   }
-  // Advance CurChild for non-skipped top-level functions and unconditionally
-  // for inlined functions.
-  if (IsTopLevelFunc)
-    CurChild += !!Cur;
-  else
-    ++CurChild;
 
   // Read number of probes in the current node.
   uint32_t NodeCount =
@@ -519,9 +514,10 @@ void MCPseudoProbeDecoder::buildAddress2ProbeMap(
     InlineTreeVec.resize(InlineTreeVec.size() + ChildrenToProcess);
     Cur->Children = MutableArrayRef(InlineTreeVec).take_back(ChildrenToProcess);
   }
-  for (uint32_t I = 0; I < ChildrenToProcess;) {
+  for (uint32_t I = 0; I < ChildrenToProcess; I++) {
     buildAddress2ProbeMap<false>(Cur, LastAddr, GuidFilter, FuncStartAddrs, I);
   }
+  return Cur;
 }
 
 template <bool IsTopLevelFunc>
@@ -630,10 +626,10 @@ bool MCPseudoProbeDecoder::buildAddress2ProbeMap(
   Data = Start;
   End = Data + Size;
   uint64_t LastAddr = 0;
-  uint32_t Child = 0;
+  uint32_t CurChildIndex = 0;
   while (Data < End)
-    buildAddress2ProbeMap<true>(&DummyInlineRoot, LastAddr, GuidFilter,
-                                FuncStartAddrs, Child);
+    CurChildIndex += buildAddress2ProbeMap<true>(
+        &DummyInlineRoot, LastAddr, GuidFilter, FuncStartAddrs, CurChildIndex);
   assert(Data == End && "Have unprocessed data in pseudo_probe section");
   return true;
 }