[SimplifyCFG] Update the name of switch generated lookup table.

[sgundapa]

Summary

This patch appends the name of the function to the switch generated lookup
table. This will ease the visual debugging in identifying the function the table
is generated from.

[hans]

Thanks! This seems useful also for nicer test files.

lib/Transforms/Utils/SimplifyCFG.cpp

4836

Could you change this to pass in a StringRef to the function name instead? That way the reader doesn't have to wonder what it needs the Function for.

[sgundapa]

Changed the patch to pass StringRef

[hans]

lgtm

lib/Transforms/Utils/SimplifyCFG.cpp

 /// This class represents a lookup table that can be used to replace a switch.
 class SwitchLookupTable {
 public:
   /// Create a lookup table to use as a switch replacement with the contents
   /// of Values, using DefaultValue to fill any holes in the table.
   SwitchLookupTable(
       Module &M, uint64_t TableSize, ConstantInt *Offset,
       const SmallVectorImpl<std::pair<ConstantInt *, Constant *>> &Values,
-      Constant *DefaultValue, const DataLayout &DL);
+      Constant *DefaultValue, const DataLayout &DL, const StringRef &FuncName);
 
   /// Build instructions with Builder to retrieve the value at
   /// the position given by Index in the lookup table.
   Value *BuildLookup(Value *Index, IRBuilder<> &Builder);
 
   /// Return true if a table with TableSize elements of
   /// type ElementType would fit in a target-legal register.
   static bool WouldFitInRegister(const DataLayout &DL, uint64_t TableSize,
private:
 
   // For ArrayKind, this is the array.
   GlobalVariable *Array;
 };
 
 } // end anonymous namespace
 
 SwitchLookupTable::SwitchLookupTable(
     Module &M, uint64_t TableSize, ConstantInt *Offset,
     const SmallVectorImpl<std::pair<ConstantInt *, Constant *>> &Values,
-    Constant *DefaultValue, const DataLayout &DL)
+    Constant *DefaultValue, const DataLayout &DL, const StringRef &FuncName)
     : SingleValue(nullptr), BitMap(nullptr), BitMapElementTy(nullptr),
       LinearOffset(nullptr), LinearMultiplier(nullptr), Array(nullptr) {
   assert(Values.size() && "Can't build lookup table without values!");
   assert(TableSize >= Values.size() && "Can't fit values in table!");
 
   // If all values in the table are equal, this is that value.
   SingleValue = Values.begin()->second;
 
SwitchLookupTable::SwitchLookupTable(
   }
 
   // Store the table in an array.
   ArrayType *ArrayTy = ArrayType::get(ValueType, TableSize);
   Constant *Initializer = ConstantArray::get(ArrayTy, TableContents);
 
   Array = new GlobalVariable(M, ArrayTy, /*constant=*/true,
                              GlobalVariable::PrivateLinkage, Initializer,
-                             "switch.table");
+                             "switch.table." + FuncName);
   Array->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
   Kind = ArrayKind;
 }
 
 Value *SwitchLookupTable::BuildLookup(Value *Index, IRBuilder<> &Builder) {
   switch (Kind) {
   case SingleValueKind:
     return SingleValue;
static bool SwitchToLookupTable(SwitchInst *SI, IRBuilder<> &Builder,
 
   bool ReturnedEarly = false;
   for (size_t I = 0, E = PHIs.size(); I != E; ++I) {
     PHINode *PHI = PHIs[I];
     const ResultListTy &ResultList = ResultLists[PHI];
 
     // If using a bitmask, use any value to fill the lookup table holes.
     Constant *DV = NeedMask ? ResultLists[PHI][0].second : DefaultResults[PHI];
-    SwitchLookupTable Table(Mod, TableSize, MinCaseVal, ResultList, DV, DL);
+    StringRef FuncName = SI->getParent()->getParent()->getName();
+    SwitchLookupTable Table(Mod, TableSize, MinCaseVal, ResultList, DV, DL,
+                            FuncName);
 
     Value *Result = Table.BuildLookup(TableIndex, Builder);
 
     // If the result is used to return immediately from the function, we want to
     // do that right here.
     if (PHI->hasOneUse() && isa<ReturnInst>(*PHI->user_begin()) &&
         PHI->user_back() == CommonDest->getFirstNonPHIOrDbg()) {
       Builder.CreateRet(Result);

test/Transforms/SimplifyCFG/X86/switch-covered-bug.ll

 ; RUN: opt -S -latesimplifycfg < %s -mtriple=x86_64-apple-darwin12.0.0 | FileCheck %s
 ; rdar://17887153
 target datalayout = "e-p:64:64:64-S128-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f16:16:16-f32:32:32-f64:64:64-f128:128:128-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-apple-darwin12.0.0"
 
 ; When we have a covered lookup table, make sure we don't delete PHINodes that
 ; are cached in PHIs.
 ; CHECK-LABEL: @test
 ; CHECK: entry:
 ; CHECK-NEXT: sub i3 %arg, -4
 ; CHECK-NEXT: zext i3 %switch.tableidx to i4
-; CHECK-NEXT: getelementptr inbounds [8 x i64], [8 x i64]* @switch.table, i32 0, i4 %switch.tableidx.zext
+; CHECK-NEXT: getelementptr inbounds [8 x i64], [8 x i64]* @switch.table.test, i32 0, i4 %switch.tableidx.zext
 ; CHECK-NEXT: load i64, i64* %switch.gep
 ; CHECK-NEXT: add i64
 ; CHECK-NEXT: ret i64
 define i64 @test(i3 %arg) {
 entry:
   switch i3 %arg, label %Default [
     i3 -2, label %Label6
     i3 1, label %Label1

test/Transforms/SimplifyCFG/X86/switch-table-bug.ll

 ; RUN: opt -S -latesimplifycfg < %s -mtriple=x86_64-apple-darwin12.0.0 | FileCheck %s
 ; rdar://17735071
 target datalayout = "e-p:64:64:64-S128-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f16:16:16-f32:32:32-f64:64:64-f128:128:128-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-apple-darwin12.0.0"
 
 ; When tableindex can't fit into i2, we should extend the type to i3.
 ; CHECK-LABEL: @_TFO6reduce1E5toRawfS0_FT_Si
 ; CHECK: entry:
 ; CHECK-NEXT: sub i2 %0, -2
 ; CHECK-NEXT: zext i2 %switch.tableidx to i3
-; CHECK-NEXT: getelementptr inbounds [4 x i64], [4 x i64]* @switch.table, i32 0, i3 %switch.tableidx.zext
+; CHECK-NEXT: getelementptr inbounds [4 x i64], [4 x i64]* @switch.table._TFO6reduce1E5toRawfS0_FT_Si, i32 0, i3 %switch.tableidx.zext
 ; CHECK-NEXT: load i64, i64* %switch.gep
 ; CHECK-NEXT: ret i64 %switch.load
 define i64 @_TFO6reduce1E5toRawfS0_FT_Si(i2) {
 entry:
   switch i2 %0, label %1 [
     i2 0, label %2
     i2 1, label %3
     i2 -2, label %4

test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll

 ; RUN: opt < %s -latesimplifycfg -S -mtriple=x86_64-unknown-linux-gnu | FileCheck %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-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 ; The table for @f
-; CHECK: @switch.table = private unnamed_addr constant [7 x i32] [i32 55, i32 123, i32 0, i32 -1, i32 27, i32 62, i32 1]
+; CHECK: @switch.table.f = private unnamed_addr constant [7 x i32] [i32 55, i32 123, i32 0, i32 -1, i32 27, i32 62, i32 1]
 
 ; The float table for @h
-; CHECK: @switch.table.1 = private unnamed_addr constant [4 x float] [float 0x40091EB860000000, float 0x3FF3BE76C0000000, float 0x4012449BA0000000, float 0x4001AE1480000000]
+; CHECK: @switch.table.h = private unnamed_addr constant [4 x float] [float 0x40091EB860000000, float 0x3FF3BE76C0000000, float 0x4012449BA0000000, float 0x4001AE1480000000]
 
 ; The table for @foostring
-; CHECK: @switch.table.2 = private unnamed_addr constant [4 x i8*] [i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str1, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str2, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str3, i64 0, i64 0)]
+; CHECK: @switch.table.foostring = private unnamed_addr constant [4 x i8*] [i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str1, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str2, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str3, i64 0, i64 0)]
 
 ; The table for @earlyreturncrash
-; CHECK: @switch.table.3 = private unnamed_addr constant [4 x i32] [i32 42, i32 9, i32 88, i32 5]
+; CHECK: @switch.table.earlyreturncrash = private unnamed_addr constant [4 x i32] [i32 42, i32 9, i32 88, i32 5]
 
-; The table for @large.
-; CHECK: @switch.table.4 = private unnamed_addr constant [199 x i32] [i32 1, i32 4, i32 9,
+; The table for @large
+; CHECK: @switch.table.large = private unnamed_addr constant [199 x i32] [i32 1, i32 4, i32 9,
 
 ; The table for @cprop
-; CHECK: @switch.table.5 = private unnamed_addr constant [7 x i32] [i32 5, i32 42, i32 126, i32 -452, i32 128, i32 6, i32 7]
+; CHECK: @switch.table.cprop = private unnamed_addr constant [7 x i32] [i32 5, i32 42, i32 126, i32 -452, i32 128, i32 6, i32 7]
 
 ; The table for @unreachable_case
-; CHECK: @switch.table.6 = private unnamed_addr constant [9 x i32] [i32 0, i32 0, i32 0, i32 2, i32 -1, i32 1, i32 1, i32 1, i32 1]
+; CHECK: @switch.table.unreachable_case = private unnamed_addr constant [9 x i32] [i32 0, i32 0, i32 0, i32 2, i32 -1, i32 1, i32 1, i32 1, i32 1]
 
 ; A simple int-to-int selection switch.
 ; It is dense enough to be replaced by table lookup.
 ; The result is directly by a ret from an otherwise empty bb,
 ; so we return early, directly from the lookup bb.
 
 define i32 @f(i32 %c) {
 entry:
return:
   ret i32 %retval.0
 
 ; CHECK-LABEL: @f(
 ; CHECK: entry:
 ; CHECK-NEXT: %switch.tableidx = sub i32 %c, 42
 ; CHECK-NEXT: %0 = icmp ult i32 %switch.tableidx, 7
 ; CHECK-NEXT: br i1 %0, label %switch.lookup, label %return
 ; CHECK: switch.lookup:
-; CHECK-NEXT: %switch.gep = getelementptr inbounds [7 x i32], [7 x i32]* @switch.table, i32 0, i32 %switch.tableidx
+; CHECK-NEXT: %switch.gep = getelementptr inbounds [7 x i32], [7 x i32]* @switch.table.f, i32 0, i32 %switch.tableidx
 ; CHECK-NEXT: %switch.load = load i32, i32* %switch.gep
 ; CHECK-NEXT: ret i32 %switch.load
 ; CHECK: return:
 ; CHECK-NEXT: ret i32 15
 }
 
 ; A switch used to initialize two variables, an i8 and a float.
 

 ; CHECK: entry:
 ; CHECK-NEXT: %switch.tableidx = sub i32 %x, 0
 ; CHECK-NEXT: %0 = icmp ult i32 %switch.tableidx, 4
 ; CHECK-NEXT: br i1 %0, label %switch.lookup, label %sw.epilog
 ; CHECK: switch.lookup:
 ; CHECK-NEXT: %switch.shiftamt = mul i32 %switch.tableidx, 8
 ; CHECK-NEXT: %switch.downshift = lshr i32 89655594, %switch.shiftamt
 ; CHECK-NEXT: %switch.masked = trunc i32 %switch.downshift to i8
-; CHECK-NEXT: %switch.gep = getelementptr inbounds [4 x float], [4 x float]* @switch.table.1, i32 0, i32 %switch.tableidx
+; CHECK-NEXT: %switch.gep = getelementptr inbounds [4 x float], [4 x float]* @switch.table.h, i32 0, i32 %switch.tableidx
 ; CHECK-NEXT: %switch.load = load float, float* %switch.gep
 ; CHECK-NEXT: br label %sw.epilog
 ; CHECK: sw.epilog:
 ; CHECK-NEXT: %a.0 = phi i8 [ %switch.masked, %switch.lookup ], [ 7, %entry ]
 ; CHECK-NEXT: %b.0 = phi float [ %switch.load, %switch.lookup ], [ 0x4023FAE140000000, %entry ]
 ; CHECK-NEXT: call void @dummy(i8 signext %a.0, float %b.0)
 ; CHECK-NEXT: ret void
 }
return:
   ret i8* %retval.0
 
 ; CHECK-LABEL: @foostring(
 ; CHECK: entry:
 ; CHECK-NEXT: %switch.tableidx = sub i32 %x, 0
 ; CHECK-NEXT: %0 = icmp ult i32 %switch.tableidx, 4
 ; CHECK-NEXT: br i1 %0, label %switch.lookup, label %return
 ; CHECK: switch.lookup:
-; CHECK-NEXT: %switch.gep = getelementptr inbounds [4 x i8*], [4 x i8*]* @switch.table.2, i32 0, i32 %switch.tableidx
+; CHECK-NEXT: %switch.gep = getelementptr inbounds [4 x i8*], [4 x i8*]* @switch.table.foostring, i32 0, i32 %switch.tableidx
 ; CHECK-NEXT: %switch.load = load i8*, i8** %switch.gep
 ; CHECK-NEXT: ret i8* %switch.load
 }
 
 ; Switch used to initialize two values. The first value is returned, the second
 ; value is not used. This used to make the transformation generate illegal code.
 
 define i32 @earlyreturncrash(i32 %x)  {

 
 sw.epilog:
   %a.0 = phi i32 [ 7, %sw.default ], [ 5, %sw.bb3 ], [ 88, %sw.bb2 ], [ 9, %sw.bb1 ], [ 42, %entry ]
   %b.0 = phi i32 [ 10, %sw.default ], [ 5, %sw.bb3 ], [ 1, %sw.bb2 ], [ 4, %sw.bb1 ], [ 3, %entry ]
   ret i32 %a.0
 
 ; CHECK-LABEL: @earlyreturncrash(
 ; CHECK: switch.lookup:
-; CHECK-NEXT: %switch.gep = getelementptr inbounds [4 x i32], [4 x i32]* @switch.table.3, i32 0, i32 %switch.tableidx
+; CHECK-NEXT: %switch.gep = getelementptr inbounds [4 x i32], [4 x i32]* @switch.table.earlyreturncrash, i32 0, i32 %switch.tableidx
 ; CHECK-NEXT: %switch.load = load i32, i32* %switch.gep
 ; CHECK-NEXT: ret i32 %switch.load
 ; CHECK: sw.epilog:
 ; CHECK-NEXT: ret i32 7
 }
 
 
 ; Example 7 from http://blog.regehr.org/archives/320
sw.default:
   br label %return
 
 return:
   %retval.0 = phi i32 [ 123, %sw.default ], [ %select, %sw.bb3 ], [ %sub, %sw.bb2 ], [ 42, %sw.bb1 ], [ 5, %entry ]
   ret i32 %retval.0
 
 ; CHECK-LABEL: @cprop(
 ; CHECK: switch.lookup:
-; CHECK: %switch.gep = getelementptr inbounds [7 x i32], [7 x i32]* @switch.table.5, i32 0, i32 %switch.tableidx
+; CHECK: %switch.gep = getelementptr inbounds [7 x i32], [7 x i32]* @switch.table.cprop, i32 0, i32 %switch.tableidx
 }
 
 define i32 @unreachable_case(i32 %x)  {
 entry:
   switch i32 %x, label %sw.default [
     i32 0, label %sw.bb
     i32 1, label %sw.bb
     i32 2, label %sw.bb

 sw.default: br label %return
 
 return:
   %retval.0 = phi i32 [ 1, %sw.bb3 ], [ -1, %sw.bb2 ], [ 0, %sw.bb ], [ 2, %sw.default ]
   ret i32 %retval.0
 
 ; CHECK-LABEL: @unreachable_case(
 ; CHECK: switch.lookup:
-; CHECK: getelementptr inbounds [9 x i32], [9 x i32]* @switch.table.6, i32 0, i32 %switch.tableidx
+; CHECK: getelementptr inbounds [9 x i32], [9 x i32]* @switch.table.unreachable_case, i32 0, i32 %switch.tableidx
 }
 
 define i32 @unreachable_default(i32 %x)  {
 entry:
   switch i32 %x, label %default [
     i32 0, label %bb0
     i32 1, label %bb1
     i32 2, label %bb2
return:
   %retval = phi i32 [ 42, %bb0 ], [ 52, %bb1 ], [ 1, %bb2 ], [ 2, %bb3 ]
   ret i32 %retval
 
 ; CHECK-LABEL: @unreachable_default(
 ; CHECK: entry:
 ; CHECK-NEXT: %switch.tableidx = sub i32 %x, 0
 ; CHECK-NOT: icmp
 ; CHECK-NOT: br 1i
-; CHECK-NEXT: %switch.gep = getelementptr inbounds [4 x i32], [4 x i32]* @switch.table.7, i32 0, i32 %switch.tableidx
+; CHECK-NEXT: %switch.gep = getelementptr inbounds [4 x i32], [4 x i32]* @switch.table.unreachable_default, i32 0, i32 %switch.tableidx
 ; CHECK-NEXT: %switch.load = load i32, i32* %switch.gep
 ; CHECK-NEXT: ret i32 %switch.load
 }
 
 ; Don't create a table with illegal type
 define i96 @illegaltype(i32 %c) {
 entry:
   switch i32 %c, label %sw.default [

 ; We build lookup tables for switches with three or more cases.
 define i32 @threecases(i32 %c) {
 ; CHECK-LABEL: @threecases(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[SWITCH_TABLEIDX:%.*]] = sub i32 %c, 0
 ; CHECK-NEXT:    [[TMP0:%.*]] = icmp ult i32 [[SWITCH_TABLEIDX]], 3
 ; CHECK-NEXT:    br i1 [[TMP0]], label %switch.lookup, label %return
 ; CHECK:       switch.lookup:
-; CHECK-NEXT:    [[SWITCH_GEP:%.*]] = getelementptr inbounds [3 x i32], [3 x i32]* @switch.table.10, i32 0, i32 [[SWITCH_TABLEIDX]]
+; CHECK-NEXT:    [[SWITCH_GEP:%.*]] = getelementptr inbounds [3 x i32], [3 x i32]* @switch.table.threecases, i32 0, i32 [[SWITCH_TABLEIDX]]
 ; CHECK-NEXT:    [[SWITCH_LOAD:%.*]] = load i32, i32* [[SWITCH_GEP]]
 ; CHECK-NEXT:    ret i32 [[SWITCH_LOAD]]
 ; CHECK:       return:
 ; CHECK-NEXT:    ret i32 3
 ;
 entry:
   switch i32 %c, label %sw.default [
   i32 0, label %return