add test coverage

Author: mingmingl-llvm

llvm/lib/Transforms/Instrumentation/MemProfUse.cpp

@@ -195,6 +195,30 @@ static bool isAllocationWithHotColdVariant(const Function *Callee,
   }
 }
 
+static void HandleUnsupportedAnnotationKinds(GlobalVariable &GVar,
+                                             AnnotationKind Kind) {
+  assert(Kind != llvm::memprof::AnnotationKind::AnnotationOK &&
+         "Should not handle AnnotationOK here");
+  SmallString<32> Reason;
+  switch (Kind) {
+  case llvm::memprof::AnnotationKind::ExplicitSection:
+    ++NumOfMemProfExplicitSectionGlobalVars;
+    Reason.append("explicit section name");
+    break;
+  case llvm::memprof::AnnotationKind::DeclForLinker:
+    Reason.append("linker declaration");
+    break;
+  case llvm::memprof::AnnotationKind::ReservedName:
+    Reason.append("name starts with `llvm.`");
+    break;
+  default:
+    llvm_unreachable("Unexpected annotation kind");
+  }
+  LLVM_DEBUG(dbgs() << "Skip annotation for " << GVar.getName() << " due to "
+                    << Reason << ".\n");
+  return;
+}
+
 struct AllocMatchInfo {
   uint64_t TotalSize = 0;
   AllocationType AllocType = AllocationType::None;
@@ -805,12 +829,8 @@ bool MemProfUsePass::annotateGlobalVariables(
     switch (Kind) {
     case llvm::memprof::AnnotationKind::AnnotationOK:
       break;
-    case llvm::memprof::AnnotationKind::ExplicitSection:
-      ++NumOfMemProfExplicitSectionGlobalVars;
-      LLVM_DEBUG(dbgs() << "Global variable " << GVar.getName()
-                        << " has explicit section name. Skip annotating.\n");
-      [[fallthrough]];
     default:
+      HandleUnsupportedAnnotationKinds(GVar, Kind);
       continue;
     }
 

llvm/test/CodeGen/X86/global-variable-partition.ll

@@ -106,23 +106,31 @@ target triple = "x86_64-unknown-linux-gnu"
 ; UNIQ-NEXT:   .section	.data.unlikely.,"aw",@progbits,unique,8
 ; AGG-NEXT:    .section	.data.unlikely.,"aw",@progbits
 
+;; The `.section` directive is omitted for .data with -unique-section-names=false.
+; See MCSectionELF::shouldOmitSectionDirective for the implementation details.
+
 ; For @data_with_unknown_hotness
 ; SYM: 	       .type	.Ldata_with_unknown_hotness,@object          # @data_with_unknown_hotness
 ; SYM:         .section .data..Ldata_with_unknown_hotness,"aw",@progbits
 ; UNIQ:        .section  .data,"aw",@progbits,unique,9
-; The `.section` directive is omitted for .data with -unique-section-names=false.
-; See MCSectionELF::shouldOmitSectionDirective for the implementation details.
+
 ; AGG:         .data
 ; COMMON:      .Ldata_with_unknown_hotness:
 
-; For @hot_data_custom_bar_section
-; It has an explicit section attribute 'var' and shouldn't have hot or unlikely suffix.
+; For variables that are not eligible for section prefix annotation
 ; COMMON:      .type hot_data_custom_bar_section,@object
 ; SYM-NEXT:    .section bar,"aw",@progbits
 ; SYM:         hot_data_custom_bar_section
 ; UNIQ:        .section bar,"aw",@progbits
 ; AGG:         .section bar,"aw",@progbits
 
+; SYM:      .section .data.llvm.fake_var,"aw"
+; UNIQ:     .section .data,"aw"
+; AGG:      .data
+
+;; No section for linker declaration
+; COMMON-NOT:  qux
+
 @.str = private unnamed_addr constant [5 x i8] c"hot\09\00", align 1
 @.str.1 = private unnamed_addr constant [10 x i8] c"%d\09%d\09%d\0A\00", align 1
 @hot_relro_array = internal constant [2 x ptr] [ptr @bss2, ptr @data3]
@@ -137,6 +145,8 @@ target triple = "x86_64-unknown-linux-gnu"
 @data3 = internal global i32 3
 @data_with_unknown_hotness = private global i32 5
 @hot_data_custom_bar_section = internal global i32 101 #0
+@llvm.fake_var = internal global i32 123
+@qux = external global i64
 
 define void @cold_func(i32 %0) !prof !15 {
   %2 = load i32, ptr @cold_bss

llvm/test/Transforms/PGOProfile/data-access-profile.ll

@@ -31,8 +31,10 @@
 ; LOG: Global variable var2.llvm.125 is annotated as hot
 ; LOG: Global variable bar is not annotated
 ; LOG: Global variable foo is annotated as unlikely
-; LOG: Global variable var3 has explicit section name. Skip annotating.
-; LOG: Global variable var4 has explicit section name. Skip annotating.
+; LOG: Skip annotation for var3 due to explicit section name.
+; LOG: Skip annotation for var4 due to explicit section name.
+; LOG: Skip annotation for llvm.fake_var due to name starts with `llvm.`.
+; LOG: Skip annotation for qux due to linker declaration.
 
 ;; String literals are not annotated.
 ; IR: @.str = unnamed_addr constant [5 x i8] c"abcde"
@@ -54,6 +56,11 @@
 ; IR-NEXT: @var3 = constant [2 x i32] [i32 12345, i32 6789], section "sec1"
 ; IR-NEXT: @var4 = constant [1 x i64] [i64 98765] #0
 
+; IR: @llvm.fake_var = global i32 123
+; IR-NOT: !section_prefix
+; IR: @qux = external global i64
+; IR-NOT: !section_prefix
+
 ; IR: attributes #0 = { "rodata-section"="sec2" }
 
 ; IR: !0 = !{!"section_prefix", !"hot"}
@@ -80,6 +87,9 @@ DataAccessProfiles:
       AccessCount:     145
   KnownColdSymbols:
     - foo
+    # The llvm.fake_var entry is added to test optimizer won't annotate it with section prefix.
+    # In real profiles, llvm.* variables may not have entries in the first place.
+    - llvm.fake_var
   KnownColdStrHashes: [ 999, 1001 ]
 ...
 ;--- memprof-no-dap.yaml
@@ -112,11 +122,14 @@ target triple = "x86_64-unknown-linux-gnu"
 @foo = global i8 2
 @var3 = constant [2 x i32][i32 12345, i32 6789], section "sec1"
 @var4 = constant [1 x i64][i64 98765] #0
+@llvm.fake_var = global i32 123
+@qux = external global i64
 
 define i32 @func() {
   %a = load i32, ptr @var1
   %b = load i32, ptr @var2.llvm.125
-  %ret = call i32 (...) @func_taking_arbitrary_param(i32 %a, i32 %b)
+  %c = load i32, ptr @llvm.fake_var
+  %ret = call i32 (...) @func_taking_arbitrary_param(i32 %a, i32 %b, i32 %c)
   ret i32 %ret
 }
 
@@ -136,5 +149,8 @@ target triple = "x86_64-unknown-linux-gnu"
 @foo = global i8 2
 @var3 = constant [2 x i32][i32 12345, i32 6789], section "sec1"
 @var4 = constant [1 x i64][i64 98765] #0
+@llvm.fake_var = global i32 123
+@qux = external global i64
+
 
 attributes #0 = { "rodata-section"="sec2" }