From 1351d17826e1efa3da3b29b6e345d44cb0ce3bc9 Mon Sep 17 00:00:00 2001
From: Mingming Liu <mingmingl@google.com>
Date: Mon, 1 Apr 2024 08:52:35 -0700
Subject: [InstrFDO][TypeProf] Implement binary instrumentation and profile
 read/write (#66825)

(The profile format change is split into a standalone change into https://github.com/llvm/llvm-project/pull/81691)

* For InstrFDO value profiling, implement instrumentation and lowering for virtual table address.
* This is controlled by `-enable-vtable-value-profiling` and off by default.
* When the option is on, raw profiles will carry serialized `VTableProfData` structs and compressed vtables as payloads.

* Implement profile reader and writer support
  * Raw profile reader is used by `llvm-profdata` but not compiler. Raw profile reader will construct InstrProfSymtab with symbol names, and map profiled runtime address to vtable symbols.
  * Indexed profile reader is used by `llvm-profdata` and compiler. When initialized, the reader stores a pointer to the beginning of in-memory compressed vtable names and the length of string. When used in `llvm-profdata`, reader decompress the string to show symbols of a profiled site. When used in compiler, string decompression doesn't
happen since IR is used to construct InstrProfSymtab.
  * Indexed profile writer collects the list of vtable names, and stores that to index profiles.
  * Text profile reader and writer support are added but mostly follow the implementation for indirect-call value type.
* `llvm-profdata show -show-vtables <args> <profile>` is implemented.

rfc in
https://discourse.llvm.org/t/rfc-dynamic-type-profiling-and-optimizations-in-llvm/74600#pick-instrumentation-points-and-instrument-runtime-types-7
---
 llvm/tools/llvm-profdata/llvm-profdata.cpp | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

(limited to 'llvm/tools/llvm-profdata/llvm-profdata.cpp')

diff --git a/llvm/tools/llvm-profdata/llvm-profdata.cpp b/llvm/tools/llvm-profdata/llvm-profdata.cpp
index e8ee3c2..0b78564 100644
--- a/llvm/tools/llvm-profdata/llvm-profdata.cpp
+++ b/llvm/tools/llvm-profdata/llvm-profdata.cpp
@@ -361,6 +361,9 @@ cl::opt<bool> ShowIndirectCallTargets(
     "ic-targets", cl::init(false),
     cl::desc("Show indirect call site target values for shown functions"),
     cl::sub(ShowSubcommand));
+cl::opt<bool> ShowVTables("show-vtables", cl::init(false),
+                          cl::desc("Show vtable names for shown functions"),
+                          cl::sub(ShowSubcommand));
 cl::opt<bool> ShowMemOPSizes(
     "memop-sizes", cl::init(false),
     cl::desc("Show the profiled sizes of the memory intrinsic calls "
@@ -739,6 +742,13 @@ static void loadInput(const WeightedFile &Input, SymbolRemapper *Remapper,
     });
   }
 
+  const InstrProfSymtab &symtab = Reader->getSymtab();
+  const auto &VTableNames = symtab.getVTableNames();
+
+  for (const auto &kv : VTableNames) {
+    WC->Writer.addVTableName(kv.getKey());
+  }
+
   if (Reader->hasTemporalProfile()) {
     auto &Traces = Reader->getTemporalProfTraces(Input.Weight);
     if (!Traces.empty())
@@ -2834,6 +2844,10 @@ static int showInstrProfile(ShowFormat SFormat, raw_fd_ostream &OS) {
         OS << "    Indirect Call Site Count: "
            << Func.getNumValueSites(IPVK_IndirectCallTarget) << "\n";
 
+      if (ShowVTables)
+        OS << "    Number of instrumented vtables: "
+           << Func.getNumValueSites(IPVK_VTableTarget) << "\n";
+
       uint32_t NumMemOPCalls = Func.getNumValueSites(IPVK_MemOPSize);
       if (ShowMemOPSizes && NumMemOPCalls > 0)
         OS << "    Number of Memory Intrinsics Calls: " << NumMemOPCalls
@@ -2855,6 +2869,13 @@ static int showInstrProfile(ShowFormat SFormat, raw_fd_ostream &OS) {
                               &(Reader->getSymtab()));
       }
 
+      if (ShowVTables) {
+        OS << "    VTable Results:\n";
+        traverseAllValueSites(Func, IPVK_VTableTarget,
+                              VPStats[IPVK_VTableTarget], OS,
+                              &(Reader->getSymtab()));
+      }
+
       if (ShowMemOPSizes && NumMemOPCalls > 0) {
         OS << "    Memory Intrinsic Size Results:\n";
         traverseAllValueSites(Func, IPVK_MemOPSize, VPStats[IPVK_MemOPSize], OS,
@@ -2903,6 +2924,11 @@ static int showInstrProfile(ShowFormat SFormat, raw_fd_ostream &OS) {
                         VPStats[IPVK_IndirectCallTarget]);
   }
 
+  if (ShownFunctions && ShowVTables) {
+    OS << "Statistics for vtable profile:\n";
+    showValueSitesStats(OS, IPVK_VTableTarget, VPStats[IPVK_VTableTarget]);
+  }
+
   if (ShownFunctions && ShowMemOPSizes) {
     OS << "Statistics for memory intrinsic calls sizes profile:\n";
     showValueSitesStats(OS, IPVK_MemOPSize, VPStats[IPVK_MemOPSize]);
-- 
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