[llvm] r227604 - Inliner: Use replaceDbgDeclareForAlloca() instead of splicing the
Adrian Prantl
aprantl at apple.com
Wed Feb 4 13:42:13 PST 2015
> On Feb 4, 2015, at 12:06 PM, Robinson, Paul <Paul_Robinson at playstation.sony.com> wrote:
>
> Hi Adrian,
> It turns out r227544 was causing a -g compilation to hang for us, I've
> attached the reduced C++ source. This patch fixed it, so I don't know
> whether you want to add this as a test case or not bother.
Thanks, I received a similar report from Alexei see the thread for r227544. I don’t really know what else to test for besides that the testcase terminates so I didn’t add a separate testcase for the infinite loop.
>
> Incidentally in looking closer at the patch, we had one question,
> see inline comment below.
> Thanks,
> --paulr
>
>> Author: adrian
>> Date: Fri Jan 30 13:37:48 2015
>> New Revision: 227604
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=227604&view=rev
>> Log:
>> Inliner: Use replaceDbgDeclareForAlloca() instead of splicing the
>> instruction and generalize it to optionally dereference the variable.
>> Follow-up to r227544.
>>
>> Modified:
>> llvm/trunk/include/llvm/Transforms/Utils/Local.h
>> llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
>> llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
>> llvm/trunk/lib/Transforms/Utils/Local.cpp
>> llvm/trunk/test/Transforms/Inline/alloca-dbgdeclare.ll
>> llvm/trunk/test/Transforms/Inline/inline_dbg_declare.ll
>>
>> Modified: llvm/trunk/include/llvm/Transforms/Utils/Local.h
>> URL: http://llvm.org/viewvc/llvm-
>> project/llvm/trunk/include/llvm/Transforms/Utils/Local.h?rev=227604&r1=227
>> 603&r2=227604&view=diff
>> ==========================================================================
>> ====
>> --- llvm/trunk/include/llvm/Transforms/Utils/Local.h (original)
>> +++ llvm/trunk/include/llvm/Transforms/Utils/Local.h Fri Jan 30 13:37:48
>> 2015
>> @@ -274,10 +274,11 @@ bool LowerDbgDeclare(Function &F);
>> /// an alloca, if any.
>> DbgDeclareInst *FindAllocaDbgDeclare(Value *V);
>>
>> -/// replaceDbgDeclareForAlloca - Replaces llvm.dbg.declare instruction
>> when
>> -/// alloca is replaced with a new value.
>> +/// \brief Replaces llvm.dbg.declare instruction when an alloca is
>> replaced with
>> +/// a new value. If Deref is true, tan additional DW_OP_deref is
>> prepended to
>> +/// the expression.
>> bool replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
>> - DIBuilder &Builder);
>> + DIBuilder &Builder, bool Deref);
>>
>> /// \brief Remove all blocks that can not be reached from the function's
>> entry.
>> ///
>>
>> Modified: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
>> URL: http://llvm.org/viewvc/llvm-
>> project/llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp?rev
>> =227604&r1=227603&r2=227604&view=diff
>> ==========================================================================
>> ====
>> --- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
>> (original)
>> +++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp Fri Jan
>> 30 13:37:48 2015
>> @@ -1739,7 +1739,7 @@ void FunctionStackPoisoner::poisonStack(
>> Value *NewAllocaPtr = IRB.CreateIntToPtr(
>> IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy,
>> Desc.Offset)),
>> AI->getType());
>> - replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB);
>> + replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB, /*Deref=*/true);
>> AI->replaceAllUsesWith(NewAllocaPtr);
>> }
>>
>>
>> Modified: llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
>> URL: http://llvm.org/viewvc/llvm-
>> project/llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp?rev=227604&r1=2
>> 27603&r2=227604&view=diff
>> ==========================================================================
>> ====
>> --- llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp (original)
>> +++ llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp Fri Jan 30 13:37:48
>> 2015
>> @@ -30,6 +30,7 @@
>> #include "llvm/IR/DataLayout.h"
>> #include "llvm/IR/DebugInfo.h"
>> #include "llvm/IR/DerivedTypes.h"
>> +#include "llvm/IR/DIBuilder.h"
>> #include "llvm/IR/Dominators.h"
>> #include "llvm/IR/IRBuilder.h"
>> #include "llvm/IR/Instructions.h"
>> @@ -1112,13 +1113,10 @@ bool llvm::InlineFunction(CallSite CS, I
>> AI, I);
>> }
>> // Move any dbg.declares describing the allocas into the entry basic
>> block.
>> + DIBuilder DIB(*Caller->getParent());
>> for (auto &I : IFI.StaticAllocas)
>> if (auto AI = dyn_cast<AllocaInst>(I))
>> - if (auto *DDI = FindAllocaDbgDeclare(AI))
>> - if (DDI->getParent() != Caller->begin())
>> - Caller->getEntryBlock().getInstList()
>> - .splice(AI->getNextNode(), FirstNewBlock->getInstList(),
>> - DDI, DDI->getNextNode());
>> + replaceDbgDeclareForAlloca(AI, AI, DIB, /*Deref=*/false);
>> }
>>
>> bool InlinedMustTailCalls = false;
>>
>> Modified: llvm/trunk/lib/Transforms/Utils/Local.cpp
>> URL: http://llvm.org/viewvc/llvm-
>> project/llvm/trunk/lib/Transforms/Utils/Local.cpp?rev=227604&r1=227603&r2=
>> 227604&view=diff
>> ==========================================================================
>> ====
>> --- llvm/trunk/lib/Transforms/Utils/Local.cpp (original)
>> +++ llvm/trunk/lib/Transforms/Utils/Local.cpp Fri Jan 30 13:37:48 2015
>> @@ -1106,10 +1106,11 @@ DbgDeclareInst *llvm::FindAllocaDbgDecla
>> }
>>
>> bool llvm::replaceDbgDeclareForAlloca(AllocaInst *AI, Value
>> *NewAllocaAddress,
>> - DIBuilder &Builder) {
>> + DIBuilder &Builder, bool Deref) {
>> DbgDeclareInst *DDI = FindAllocaDbgDeclare(AI);
>> if (!DDI)
>> return false;
>> + DebugLoc Loc = DDI->getDebugLoc();
>> DIVariable DIVar(DDI->getVariable());
>> DIExpression DIExpr(DDI->getExpression());
>> assert((!DIVar || DIVar.isVariable()) &&
>> @@ -1117,21 +1118,24 @@ bool llvm::replaceDbgDeclareForAlloca(Al
>> if (!DIVar)
>> return false;
>>
>> - // Create a copy of the original DIDescriptor for user variable,
>> prepending
>> - // "deref" operation to a list of address elements, as new
>> llvm.dbg.declare
>> - // will take a value storing address of the memory for variable, not
>> - // alloca itself.
>> - SmallVector<int64_t, 4> NewDIExpr;
>> - NewDIExpr.push_back(dwarf::DW_OP_deref);
>> - if (DIExpr)
>> - for (unsigned i = 0, n = DIExpr.getNumElements(); i < n; ++i)
>> - NewDIExpr.push_back(DIExpr.getElement(i));
>> + if (Deref) {
>> + // Create a copy of the original DIDescriptor for user variable,
>> prepending
>> + // "deref" operation to a list of address elements, as new
>> llvm.dbg.declare
>> + // will take a value storing address of the memory for variable, not
>> + // alloca itself.
>> + SmallVector<int64_t, 4> NewDIExpr;
>> + NewDIExpr.push_back(dwarf::DW_OP_deref);
>> + if (DIExpr)
>
> Does it really happen that you have Deref true but no DIExpr?
> The result would be a DWARF expression consisting of just a deref.
Not sure if I got the question — this seems to be the common usecase in Transforms/Instrumentations/AddressSanitizer.cpp were normal variables are lowered into indirect references inside a buffer.
-- adrian
>
>> + for (unsigned i = 0, n = DIExpr.getNumElements(); i < n; ++i)
>> + NewDIExpr.push_back(DIExpr.getElement(i));
>> + DIExpr = Builder.createExpression(NewDIExpr);
>> + }
>>
>> // Insert llvm.dbg.declare in the same basic block as the original
>> alloca,
>> // and remove old llvm.dbg.declare.
>> BasicBlock *BB = AI->getParent();
>> - Builder.insertDeclare(NewAllocaAddress, DIVar,
>> - Builder.createExpression(NewDIExpr), BB);
>> + Builder.insertDeclare(NewAllocaAddress, DIVar, DIExpr, BB)
>> + ->setDebugLoc(Loc);
>> DDI->eraseFromParent();
>> return true;
>> }
>>
>> Modified: llvm/trunk/test/Transforms/Inline/alloca-dbgdeclare.ll
>> URL: http://llvm.org/viewvc/llvm-
>> project/llvm/trunk/test/Transforms/Inline/alloca-
>> dbgdeclare.ll?rev=227604&r1=227603&r2=227604&view=diff
>> ==========================================================================
>> ====
>> --- llvm/trunk/test/Transforms/Inline/alloca-dbgdeclare.ll (original)
>> +++ llvm/trunk/test/Transforms/Inline/alloca-dbgdeclare.ll Fri Jan 30
>> 13:37:48 2015
>> @@ -40,7 +40,7 @@ entry:
>> ; CHECK: define void @_Z3fn5v()
>> ; CHECK-NEXT: entry:
>> ; CHECK-NEXT: %agg.tmp.sroa.3.i = alloca [20 x i8], align 4
>> -; CHECK-NEXT: tail call void @llvm.dbg.declare(metadata [20 x i8]*
>> %agg.tmp.sroa.3.i,
>> +; CHECK-NEXT: call void @llvm.dbg.declare(metadata [20 x i8]*
>> %agg.tmp.sroa.3.i,
>> %agg.tmp.sroa.3 = alloca [20 x i8], align 4
>> tail call void @llvm.dbg.declare(metadata [20 x i8]* %agg.tmp.sroa.3,
>> metadata !46, metadata !48), !dbg !49
>> %agg.tmp.sroa.0.0.copyload = load i32* getelementptr inbounds
>> (%struct.A* @b, i64 0, i32 0), align 8, !dbg !50
>>
>> Modified: llvm/trunk/test/Transforms/Inline/inline_dbg_declare.ll
>> URL: http://llvm.org/viewvc/llvm-
>> project/llvm/trunk/test/Transforms/Inline/inline_dbg_declare.ll?rev=227604
>> &r1=227603&r2=227604&view=diff
>> ==========================================================================
>> ====
>> --- llvm/trunk/test/Transforms/Inline/inline_dbg_declare.ll (original)
>> +++ llvm/trunk/test/Transforms/Inline/inline_dbg_declare.ll Fri Jan 30
>> 13:37:48 2015
>> @@ -92,6 +92,6 @@ attributes #1 = { nounwind readnone }
>> !22 = !MDLocation(line: 8, column: 14, scope: !9)
>> !23 = !MDLocation(line: 9, column: 1, scope: !9)
>>
>> -; CHECK: [[m23]] = !{!"0x101\00x\0016777217\000", !4, !5, !8,
>> [[CALL_SITE:![0-9]*]]} ; [ DW_TAG_arg_variable ] [x] [line 1]
>> -; CHECK: [[CALL_SITE]] = distinct !MDLocation(line: 8, column: 14, scope:
>> !9)
>> +; CHECK: [[CALL_SITE:![0-9]+]] = distinct !MDLocation(line: 8, column:
>> 14, scope: !9)
>> +; CHECK: [[m23]] = !{!"0x101\00x\0016777217\000", !4, !5, !8,
>> [[CALL_SITE]]} ; [ DW_TAG_arg_variable ] [x] [line 1]
>> ; CHECK: [[m24]] = !MDLocation(line: 1, column: 17, scope: !4, inlinedAt:
>> [[CALL_SITE]])
>>
>>
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