[llvm] r240039 - [CallGraph] Teach the CallGraph about non-leaf intrinsics.
Sanjoy Das
sanjoy at playingwithpointers.com
Fri Jun 19 13:28:20 PDT 2015
I think -print-callgraph (all print functions, actually) should be
deterministic within reason. I'll put up a review fixing this
shortly.
On Fri, Jun 19, 2015 at 1:12 PM, Justin Bogner <mail at justinbogner.com> wrote:
> Sanjoy Das <sanjoy at playingwithpointers.com> writes:
>> Author: sanjoy
>> Date: Thu Jun 18 14:28:26 2015
>> New Revision: 240039
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=240039&view=rev
>> Log:
>> [CallGraph] Teach the CallGraph about non-leaf intrinsics.
>>
>> Summary:
>> Currently intrinsics don't affect the creation of the call graph.
>> This is not accurate with respect to statepoint and patchpoint
>> intrinsics -- these do call (or invoke) LLVM level functions.
>>
>> This change fixes this inconsistency by adding a call to the external
>> node for call sites that call these non-leaf intrinsics. This coupled
>> with the fact that these intrinsics also escape the function pointer
>> they call gives us a conservatively correct call graph.
>>
>> Reviewers: reames, chandlerc, atrick, pgavlin
>>
>> Subscribers: llvm-commits
>>
>> Differential Revision: http://reviews.llvm.org/D10526
>>
>> Added:
>> llvm/trunk/test/Analysis/CallGraph/non-leaf-intrinsics.ll
>> Modified:
>> llvm/trunk/include/llvm/Analysis/CallGraph.h
>> llvm/trunk/include/llvm/IR/Intrinsics.h
>> llvm/trunk/lib/Analysis/IPA/CallGraph.cpp
>> llvm/trunk/lib/Analysis/IPA/CallGraphSCCPass.cpp
>> llvm/trunk/lib/IR/Function.cpp
>>
>> Modified: llvm/trunk/include/llvm/Analysis/CallGraph.h
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/CallGraph.h?rev=240039&r1=240038&r2=240039&view=diff
>> ==============================================================================
>> --- llvm/trunk/include/llvm/Analysis/CallGraph.h (original)
>> +++ llvm/trunk/include/llvm/Analysis/CallGraph.h Thu Jun 18 14:28:26 2015
>> @@ -56,6 +56,7 @@
>> #include "llvm/ADT/STLExtras.h"
>> #include "llvm/IR/CallSite.h"
>> #include "llvm/IR/Function.h"
>> +#include "llvm/IR/Intrinsics.h"
>> #include "llvm/IR/ValueHandle.h"
>> #include "llvm/Pass.h"
>> #include <map>
>> @@ -229,7 +230,8 @@ public:
>> /// \brief Adds a function to the list of functions called by this one.
>> void addCalledFunction(CallSite CS, CallGraphNode *M) {
>> assert(!CS.getInstruction() || !CS.getCalledFunction() ||
>> - !CS.getCalledFunction()->isIntrinsic());
>> + !CS.getCalledFunction()->isIntrinsic() ||
>> + !Intrinsic::isLeaf(CS.getCalledFunction()->getIntrinsicID()));
>> CalledFunctions.emplace_back(CS.getInstruction(), M);
>> M->AddRef();
>> }
>>
>> Modified: llvm/trunk/include/llvm/IR/Intrinsics.h
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/Intrinsics.h?rev=240039&r1=240038&r2=240039&view=diff
>> ==============================================================================
>> --- llvm/trunk/include/llvm/IR/Intrinsics.h (original)
>> +++ llvm/trunk/include/llvm/IR/Intrinsics.h Thu Jun 18 14:28:26 2015
>> @@ -52,6 +52,11 @@ namespace Intrinsic {
>> /// Returns true if the intrinsic can be overloaded.
>> bool isOverloaded(ID id);
>>
>> + /// Returns true if the intrinsic is a leaf, i.e. it does not make any calls
>> + /// itself. Most intrinsics are leafs, the exceptions being the patchpoint
>> + /// and statepoint intrinsics. These call (or invoke) their "target" argument.
>> + bool isLeaf(ID id);
>> +
>> /// Return the attributes for an intrinsic.
>> AttributeSet getAttributes(LLVMContext &C, ID id);
>>
>>
>> Modified: llvm/trunk/lib/Analysis/IPA/CallGraph.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/IPA/CallGraph.cpp?rev=240039&r1=240038&r2=240039&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Analysis/IPA/CallGraph.cpp (original)
>> +++ llvm/trunk/lib/Analysis/IPA/CallGraph.cpp Thu Jun 18 14:28:26 2015
>> @@ -79,8 +79,10 @@ void CallGraph::addToCallGraph(Function
>> CallSite CS(cast<Value>(II));
>> if (CS) {
>> const Function *Callee = CS.getCalledFunction();
>> - if (!Callee)
>> + if (!Callee || !Intrinsic::isLeaf(Callee->getIntrinsicID()))
>> // Indirect calls of intrinsics are not allowed so no need to check.
>> + // We can be more precise here by using TargetArg returned by
>> + // Intrinsic::isLeaf.
>> Node->addCalledFunction(CS, CallsExternalNode);
>> else if (!Callee->isIntrinsic())
>> Node->addCalledFunction(CS, getOrInsertFunction(Callee));
>>
>> Modified: llvm/trunk/lib/Analysis/IPA/CallGraphSCCPass.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/IPA/CallGraphSCCPass.cpp?rev=240039&r1=240038&r2=240039&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Analysis/IPA/CallGraphSCCPass.cpp (original)
>> +++ llvm/trunk/lib/Analysis/IPA/CallGraphSCCPass.cpp Thu Jun 18 14:28:26 2015
>> @@ -217,8 +217,10 @@ bool CGPassManager::RefreshCallGraph(Cal
>> // another value. This can happen when constant folding happens
>> // of well known functions etc.
>> !CallSite(I->first) ||
>> - (CallSite(I->first).getCalledFunction() &&
>> - CallSite(I->first).getCalledFunction()->isIntrinsic())) {
>> + (CallSite(I->first).getCalledFunction() &&
>> + CallSite(I->first).getCalledFunction()->isIntrinsic() &&
>> + Intrinsic::isLeaf(
>> + CallSite(I->first).getCalledFunction()->getIntrinsicID()))) {
>> assert(!CheckingMode &&
>> "CallGraphSCCPass did not update the CallGraph correctly!");
>>
>>
>> Modified: llvm/trunk/lib/IR/Function.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Function.cpp?rev=240039&r1=240038&r2=240039&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/IR/Function.cpp (original)
>> +++ llvm/trunk/lib/IR/Function.cpp Thu Jun 18 14:28:26 2015
>> @@ -846,6 +846,18 @@ bool Intrinsic::isOverloaded(ID id) {
>> #undef GET_INTRINSIC_OVERLOAD_TABLE
>> }
>>
>> +bool Intrinsic::isLeaf(ID id) {
>> + switch (id) {
>> + default:
>> + return true;
>> +
>> + case Intrinsic::experimental_gc_statepoint:
>> + case Intrinsic::experimental_patchpoint_void:
>> + case Intrinsic::experimental_patchpoint_i64:
>> + return false;
>> + }
>> +}
>> +
>> /// This defines the "Intrinsic::getAttributes(ID id)" method.
>> #define GET_INTRINSIC_ATTRIBUTES
>> #include "llvm/IR/Intrinsics.gen"
>>
>> Added: llvm/trunk/test/Analysis/CallGraph/non-leaf-intrinsics.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/CallGraph/non-leaf-intrinsics.ll?rev=240039&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/Analysis/CallGraph/non-leaf-intrinsics.ll (added)
>> +++ llvm/trunk/test/Analysis/CallGraph/non-leaf-intrinsics.ll Thu Jun 18 14:28:26 2015
>> @@ -0,0 +1,32 @@
>> +; RUN: opt -S -print-callgraph -disable-output < %s 2>&1 | FileCheck %s
>> +
>> +declare void @llvm.experimental.patchpoint.void(i64, i32, i8*, i32, ...)
>> +declare i32 @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...)
>> +
>> +define private void @f() {
>> + ret void
>> +}
>> +
>> +define void @calls_statepoint(i8 addrspace(1)* %arg) gc "statepoint-example" {
>> +entry:
>> + %cast = bitcast i8 addrspace(1)* %arg to i64 addrspace(1)*
>> + %safepoint_token = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @f, i32 0, i32 0, i32 0, i32 5, i32 0, i32 0, i32 0, i32 10, i32 0, i8 addrspace(1)* %arg, i64 addrspace(1)* %cast, i8 addrspace(1)* %arg, i8 addrspace(1)* %arg)
>> + ret void
>> +}
>> +
>> +define void @calls_patchpoint() {
>> +entry:
>> + %c = bitcast void()* @f to i8*
>> + tail call void (i64, i32, i8*, i32, ...) @llvm.experimental.patchpoint.void(i64 1, i32 15, i8* %c, i32 0, i16 65535, i16 -1, i32 65536, i32 2000000000, i32 2147483647, i32 -1, i32 4294967295, i32 4294967296, i64 2147483648, i64 4294967295, i64 4294967296, i64 -1)
>> + ret void
>> +}
>> +
>> +
>> +; CHECK: Call graph node <<null function>>
>> +; CHECK: CS<0x0> calls function 'f'
>> +
>> +; CHECK: Call graph node for function: 'calls_statepoint'
>> +; CHECK-NEXT: CS<[[addr_0:[^>]+]]> calls external node
>> +
>> +; CHECK: Call graph node for function: 'calls_patchpoint'
>> +; CHECK-NEXT: CS<[[addr_1:[^>]+]]> calls external node
>
> The order that these call graph nodes are emitted seems to change when I
> run the tests under asan+ubsan. That is, the test outputs:
>
> Call graph node <<null function>><<0x6040000041d0>> #uses=0
> CS<0x0> calls function 'llvm.experimental.patchpoint.void'
> CS<0x0> calls function 'llvm.experimental.gc.statepoint.p0f_isVoidf'
> CS<0x0> calls function 'f'
> CS<0x0> calls function 'calls_statepoint'
> CS<0x0> calls function 'calls_patchpoint'
>
> Call graph node for function: 'calls_patchpoint'<<0x604000003f10>> #uses=1
> CS<0x61500000f218> calls external node
>
> Call graph node for function: 'calls_statepoint'<<0x604000003f90>> #uses=1
> CS<0x61500000f498> calls external node
>
> Does it make sense loosen this test to accept the output in either
> order, or does this look like an issue with -print-callgraph?
>
>>
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