[PATCH] D124703: [memprof] Don't instrument PGO and other compiler inserted variables

[Teresa Johnson via Phabricator via llvm-commits]

tejohnson updated this revision to Diff 426464.
tejohnson added a comment.

Address comments. Remove now unrelated change.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124703/new/

https://reviews.llvm.org/D124703

Files:
  llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
  llvm/test/Instrumentation/HeapProfiler/skip-compiler-inserted.ll


Index: llvm/test/Instrumentation/HeapProfiler/skip-compiler-inserted.ll
===================================================================
--- /dev/null
+++ llvm/test/Instrumentation/HeapProfiler/skip-compiler-inserted.ll
@@ -0,0 +1,47 @@
+;; Test that we don't instrument loads to PGO counters or other
+;; compiler inserted variables.
+;
+; RUN: opt < %s -passes='function(memprof),module(memprof-module)' -S | FileCheck --check-prefixes=CHECK %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+target triple = "x86_64-unknown-linux-gnu"
+
+$__profc__Z3foov = comdat nodeduplicate
+ at __profc__Z3foov = private global [1 x i64] zeroinitializer, section "__llvm_prf_cnts", comdat, align 8
+ at __llvm_gcov_ctr = internal global [1 x i64] zeroinitializer
+
+define void @_Z3foov(i32* %a) {
+entry:
+  ;; Load that should get instrumentation.
+  %tmp1 = load i32, i32* %a, align 4
+  ;; PGO counter update
+  %pgocount = load i64, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3foov, i64 0, i64 0), align 8
+  %0 = add i64 %pgocount, 1
+  store i64 %0, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3foov, i64 0, i64 0), align 8
+  ;; Gcov counter update
+  %gcovcount = load i64, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__llvm_gcov_ctr, i64 0, i64 0), align 8
+  %1 = add i64 %gcovcount, 1
+  store i64 %1, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__llvm_gcov_ctr, i64 0, i64 0), align 8
+  ret void
+}
+
+;; We should only add memory profile instrumentation for the first load.
+; CHECK: define void @_Z3foov
+; CHECK-NEXT: entry:
+; CHECK-NEXT:  %0 = load i64, i64* @__memprof_shadow_memory_dynamic_address, align 8
+; CHECK-NEXT:  %1 = ptrtoint i32* %a to i64
+; CHECK-NEXT:  %2 = and i64 %1, -64
+; CHECK-NEXT:  %3 = lshr i64 %2, 3
+; CHECK-NEXT:  %4 = add i64 %3, %0
+; CHECK-NEXT:  %5 = inttoptr i64 %4 to i64*
+; CHECK-NEXT:  %6 = load i64, i64* %5, align 8
+; CHECK-NEXT:  %7 = add i64 %6, 1
+; CHECK-NEXT:  store i64 %7, i64* %5, align 8
+; CHECK-NEXT:  %tmp1 = load i32, i32* %a, align 4
+; CHECK-NEXT:  %pgocount = load i64, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3foov, i64 0, i64 0)
+; CHECK-NEXT:  %8 = add i64 %pgocount, 1
+; CHECK-NEXT:  store i64 %8, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3foov, i64 0, i64 0)
+; CHECK-NEXT:  %gcovcount = load i64, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__llvm_gcov_ctr, i64 0, i64 0)
+; CHECK-NEXT:  %9 = add i64 %gcovcount, 1
+; CHECK-NEXT:  store i64 %9, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__llvm_gcov_ctr, i64 0, i64 0)
+; CHECK-NEXT:  ret void
Index: llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
+++ llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
@@ -32,6 +32,7 @@
 #include "llvm/IR/Value.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
+#include "llvm/ProfileData/InstrProf.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
@@ -408,6 +409,25 @@
   if (Access.Addr->isSwiftError())
     return None;
 
+  // Peel off GEPs and BitCasts.
+  auto *Addr = Access.Addr->stripInBoundsOffsets();
+
+  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) {
+    // Do not instrument PGO counter updates.
+    if (GV->hasSection()) {
+      StringRef SectionName = GV->getSection();
+      // Check if the global is in the PGO counters section.
+      auto OF = Triple(I->getModule()->getTargetTriple()).getObjectFormat();
+      if (SectionName.endswith(
+              getInstrProfSectionName(IPSK_cnts, OF, /*AddSegmentInfo=*/false)))
+        return None;
+    }
+
+    // Do not instrument accesses to LLVM internal variables.
+    if (GV->getName().startswith("__llvm"))
+      return None;
+  }
+
   const DataLayout &DL = I->getModule()->getDataLayout();
   Access.TypeSize = DL.getTypeStoreSizeInBits(Access.AccessTy);
   return Access;


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D124703.426464.patch
Type: text/x-patch
Size: 4173 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220502/992b52a8/attachment.bin>