[llvm] [llvm][ctx_profile] Add the `llvm.instrprof.callsite` intrinsic (PR #89939)

[Mircea Trofin via llvm-commits]

https://github.com/mtrofin created https://github.com/llvm/llvm-project/pull/89939

Add the callsite intrinsic. 

Structurally, it is very similar to the counter intrinsics, hence the inheritance relationship. We can probably rename later `InstrProfCntrInstBase` to `InstrProfIndexedBase` later - because the "counting" aspect is really left to derived types of `InstrProfCntrInstBase`, and it only concerns itself with the index aspect (which is what we care about for `callsite`, too)

(Tracking Issue: #89287, RFC referenced there)

>From 848deeaf16a1d8a54bbeb6256f2a4a85122703c9 Mon Sep 17 00:00:00 2001
From: Mircea Trofin <mtrofin at google.com>
Date: Wed, 24 Apr 2024 07:51:55 -0700
Subject: [PATCH] [llvm][ctx_profile] Add the `llvm.instrprof.callsite`
 intrinsic

(Tracking Issue: #89287, RFC referenced there)
---
 llvm/include/llvm/IR/IntrinsicInst.h | 16 ++++++++++++++++
 llvm/include/llvm/IR/Intrinsics.td   |  5 +++++
 llvm/unittests/IR/IntrinsicsTest.cpp |  2 ++
 3 files changed, 23 insertions(+)

diff --git a/llvm/include/llvm/IR/IntrinsicInst.h b/llvm/include/llvm/IR/IntrinsicInst.h
index 4f22720f1c558d..8a137ffe28b9f8 100644
--- a/llvm/include/llvm/IR/IntrinsicInst.h
+++ b/llvm/include/llvm/IR/IntrinsicInst.h
@@ -1435,6 +1435,7 @@ class InstrProfInstBase : public IntrinsicInst {
     case Intrinsic::instrprof_cover:
     case Intrinsic::instrprof_increment:
     case Intrinsic::instrprof_increment_step:
+    case Intrinsic::instrprof_callsite:
     case Intrinsic::instrprof_timestamp:
     case Intrinsic::instrprof_value_profile:
       return true;
@@ -1519,6 +1520,21 @@ class InstrProfIncrementInstStep : public InstrProfIncrementInst {
   }
 };
 
+/// This represents the llvm.instrprof.increment intrinsic.
+/// It is structurally like the increment or step counters, hence the
+/// inheritance relationship, albeit somewhat tenuous (it's not 'counting' per
+/// se)
+class InstrProfCallsite : public InstrProfCntrInstBase {
+public:
+  static bool classof(const IntrinsicInst *I) {
+    return I->getIntrinsicID() == Intrinsic::instrprof_callsite;
+  }
+  static bool classof(const Value *V) {
+    return isa<IntrinsicInst>(V) && classof(cast<IntrinsicInst>(V));
+  }
+  Value *getCallee() const;
+};
+
 /// This represents the llvm.instrprof.timestamp intrinsic.
 class InstrProfTimestampInst : public InstrProfCntrInstBase {
 public:
diff --git a/llvm/include/llvm/IR/Intrinsics.td b/llvm/include/llvm/IR/Intrinsics.td
index 1d20f7e1b19854..a14e9dedef8c9e 100644
--- a/llvm/include/llvm/IR/Intrinsics.td
+++ b/llvm/include/llvm/IR/Intrinsics.td
@@ -914,6 +914,11 @@ def int_instrprof_increment_step : Intrinsic<[],
                                         [llvm_ptr_ty, llvm_i64_ty,
                                          llvm_i32_ty, llvm_i32_ty, llvm_i64_ty]>;
 
+// Callsite instrumentation for contextual profiling
+def int_instrprof_callsite : Intrinsic<[],
+                                        [llvm_ptr_ty, llvm_i64_ty,
+                                         llvm_i32_ty, llvm_i32_ty, llvm_ptr_ty]>;
+
 // A timestamp for instrumentation based profiling.
 def int_instrprof_timestamp : Intrinsic<[], [llvm_ptr_ty, llvm_i64_ty,
                                              llvm_i32_ty, llvm_i32_ty]>;
diff --git a/llvm/unittests/IR/IntrinsicsTest.cpp b/llvm/unittests/IR/IntrinsicsTest.cpp
index 3fa4b2cf73b6be..dddd2f73d4446b 100644
--- a/llvm/unittests/IR/IntrinsicsTest.cpp
+++ b/llvm/unittests/IR/IntrinsicsTest.cpp
@@ -81,6 +81,7 @@ TEST_F(IntrinsicsTest, InstrProfInheritance) {
   __ISA(InstrProfCoverInst, InstrProfCntrInstBase);
   __ISA(InstrProfIncrementInst, InstrProfCntrInstBase);
   __ISA(InstrProfIncrementInstStep, InstrProfIncrementInst);
+  __ISA(InstrProfCallsite, InstrProfCntrInstBase);
   __ISA(InstrProfTimestampInst, InstrProfCntrInstBase);
   __ISA(InstrProfValueProfileInst, InstrProfCntrInstBase);
   __ISA(InstrProfMCDCBitmapInstBase, InstrProfInstBase);
@@ -94,6 +95,7 @@ TEST_F(IntrinsicsTest, InstrProfInheritance) {
           {Intrinsic::instrprof_cover, isInstrProfCoverInst},
           {Intrinsic::instrprof_increment, isInstrProfIncrementInst},
           {Intrinsic::instrprof_increment_step, isInstrProfIncrementInstStep},
+          {Intrinsic::instrprof_callsite, isInstrProfCallsite},
           {Intrinsic::instrprof_mcdc_condbitmap_update,
            isInstrProfMCDCCondBitmapUpdate},
           {Intrinsic::instrprof_mcdc_parameters,