[llvm] r336419 - CallGraphSCCPass: iterate over all functions.
Mikael Holmén via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 9 01:21:21 PDT 2018
Hi Tim,
I found a case which started going wrong with this patch. I don't know
if it's the patch itself that is the problem or if it's just exposing
somethng already existing.
With
opt -S -o - foo.ll -argpromotion -instcombine
I get
DISubprogram attached to more than one function
!1 = distinct !DISubprogram(name: "func_27", scope: !2, file: !2, line:
251, type: !3, isLocal: true, isDefinition: true, scopeLine: 252,
isOptimized: false, unit: !5)
i64 ()* @func_27
LLVM ERROR: Broken module found, compilation aborted!
If I add -print-before-all -print-after-all -print-module-scope I get
this as the last printouts:
*** IR Dump Before Module Verifier *** (function: func_27)
; ModuleID = 'foo.ll'
source_filename = "foo.ll"
@g_280 = external global i32
define i32 @func_1() {
bb1:
%l_55.115 = alloca i32*, align 8
%_tmp555 = load i32*, i32** %l_55.115, align 8
%0 = call i64 @func_27()
ret i32 undef
}
define internal i64 @func_27() !dbg !1 {
store i32* @g_280, i32** undef, align 8
ret i64 undef
}
define i16 @func_28() {
%_tmp5791 = call i32 @func_1()
ret i16 undef
}
!llvm.dbg.cu = !{}
!llvm.module.flags = !{!0}
!0 = !{i32 2, !"Debug Info Version", i32 3}
!1 = distinct !DISubprogram(name: "func_27", scope: !2, file: !2, line:
251, type: !3, isLocal: true, isDefinition: true, scopeLine: 252,
isOptimized: false, unit: !5)
!2 = !DIFile(filename: "foo.c", directory: "/bar")
!3 = !DISubroutineType(types: !4)
!4 = !{}
!5 = distinct !DICompileUnit(language: DW_LANG_C, file: !2, producer:
"My compiler", isOptimized: false, runtimeVersion: 0, emissionKind:
LineTablesOnly)
DISubprogram attached to more than one function
!1 = distinct !DISubprogram(name: "func_27", scope: !2, file: !2, line:
251, type: !3, isLocal: true, isDefinition: true, scopeLine: 252,
isOptimized: false, unit: !5)
i64 ()* @func_27
*** IR Dump After Module Verifier *** (function: func_27)
; ModuleID = 'foo.ll'
source_filename = "foo.ll"
@g_280 = external global i32
define i32 @func_1() {
bb1:
%l_55.115 = alloca i32*, align 8
%_tmp555 = load i32*, i32** %l_55.115, align 8
%0 = call i64 @func_27()
ret i32 undef
}
define internal i64 @func_27() !dbg !1 {
store i32* @g_280, i32** undef, align 8
ret i64 undef
}
define i16 @func_28() {
%_tmp5791 = call i32 @func_1()
ret i16 undef
}
!llvm.dbg.cu = !{}
!llvm.module.flags = !{!0}
!0 = !{i32 2, !"Debug Info Version", i32 3}
!1 = distinct !DISubprogram(name: "func_27", scope: !2, file: !2, line:
251, type: !3, isLocal: true, isDefinition: true, scopeLine: 252,
isOptimized: false, unit: !5)
!2 = !DIFile(filename: "foo.c", directory: "/bar")
!3 = !DISubroutineType(types: !4)
!4 = !{}
!5 = distinct !DICompileUnit(language: DW_LANG_C, file: !2, producer:
"My compiler", isOptimized: false, runtimeVersion: 0, emissionKind:
LineTablesOnly)
LLVM ERROR: Broken module found, compilation aborted!
As far as I can see in the printouts !1 is only used on func_27 and
still it complains.
func27 was changed during argpromotion:
ARG PROMOTION: Promoting to:
declare !dbg !0 internal i64 @func_27(i32*)
From:
define internal i64 @func_27(i32* %p1, i32* %p2) {
store i32* %p1, i32** undef
store i32* @g_280, i32** undef
ret i64 undef
}
so I'm not sure if the old func_27 is still hanging around in some way?
Should I write a PR on this or do you understand what's going on?
Regards,
Mikael
On 07/06/2018 10:04 AM, Tim Northover via llvm-commits wrote:
> Author: tnorthover
> Date: Fri Jul 6 01:04:47 2018
> New Revision: 336419
>
> URL: http://llvm.org/viewvc/llvm-project?rev=336419&view=rev
> Log:
> CallGraphSCCPass: iterate over all functions.
>
> Previously we only iterated over functions reachable from the set of
> external functions in the module. But since some of the passes under
> this (notably the always-inliner and coroutine lowerer) are required for
> correctness, they need to run over everything.
>
> This just adds an extra layer of iteration over the CallGraph to keep
> track of which functions we've already visited and get the next batch of
> SCCs.
>
> Should fix PR38029.
>
> Modified:
> llvm/trunk/include/llvm/ADT/SCCIterator.h
> llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp
> llvm/trunk/test/Transforms/Inline/always-inline.ll
>
> Modified: llvm/trunk/include/llvm/ADT/SCCIterator.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/SCCIterator.h?rev=336419&r1=336418&r2=336419&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/ADT/SCCIterator.h (original)
> +++ llvm/trunk/include/llvm/ADT/SCCIterator.h Fri Jul 6 01:04:47 2018
> @@ -90,6 +90,7 @@ class scc_iterator : public iterator_fac
> /// Compute the next SCC using the DFS traversal.
> void GetNextSCC();
>
> +public:
> scc_iterator(NodeRef entryN) : visitNum(0) {
> DFSVisitOne(entryN);
> GetNextSCC();
> @@ -98,12 +99,6 @@ class scc_iterator : public iterator_fac
> /// End is when the DFS stack is empty.
> scc_iterator() = default;
>
> -public:
> - static scc_iterator begin(const GraphT &G) {
> - return scc_iterator(GT::getEntryNode(G));
> - }
> - static scc_iterator end(const GraphT &) { return scc_iterator(); }
> -
> /// Direct loop termination test which is more efficient than
> /// comparison with \c end().
> bool isAtEnd() const {
> @@ -222,16 +217,25 @@ bool scc_iterator<GraphT, GT>::hasLoop()
> return false;
> }
>
> -/// Construct the begin iterator for a deduced graph type T.
> +/// Construct the begin iterator for a deduced graph type T, starting from its
> +/// entry node.
> template <class T> scc_iterator<T> scc_begin(const T &G) {
> - return scc_iterator<T>::begin(G);
> + return scc_iterator<T>(GraphTraits<T>::getEntryNode(G));
> }
>
> -/// Construct the end iterator for a deduced graph type T.
> +/// Construct the begin iterator for a graph type T, starting from the specified
> +/// node.
> +template <class T, class U = GraphTraits<T>>
> +scc_iterator<T, U> scc_begin(typename U::NodeRef N) {
> + return scc_iterator<T>(N);
> +}
> +
> + /// Construct the end iterator for a deduced graph type T.
> template <class T> scc_iterator<T> scc_end(const T &G) {
> - return scc_iterator<T>::end(G);
> + return scc_iterator<T>();
> }
>
> +
> } // end namespace llvm
>
> #endif // LLVM_ADT_SCCITERATOR_H
>
> Modified: llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp?rev=336419&r1=336418&r2=336419&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp (original)
> +++ llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp Fri Jul 6 01:04:47 2018
> @@ -17,6 +17,7 @@
>
> #include "llvm/Analysis/CallGraphSCCPass.h"
> #include "llvm/ADT/DenseMap.h"
> +#include "llvm/ADT/DenseSet.h"
> #include "llvm/ADT/SCCIterator.h"
> #include "llvm/ADT/Statistic.h"
> #include "llvm/Analysis/CallGraph.h"
> @@ -63,6 +64,10 @@ public:
> /// whether any of the passes modifies the module, and if so, return true.
> bool runOnModule(Module &M) override;
>
> + /// Execute all of the passes scheduled for execution on a given SCC. Return
> + /// true if any passes modify the module.
> + bool runOnSCC(CallGraphSCC &SCC, CallGraph &CG);
> +
> using ModulePass::doInitialization;
> using ModulePass::doFinalization;
>
> @@ -448,51 +453,78 @@ bool CGPassManager::RunAllPassesOnSCC(Ca
> bool CGPassManager::runOnModule(Module &M) {
> CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
> bool Changed = doInitialization(CG);
> -
> - // Walk the callgraph in bottom-up SCC order.
> - scc_iterator<CallGraph*> CGI = scc_begin(&CG);
>
> - CallGraphSCC CurSCC(CG, &CGI);
> - while (!CGI.isAtEnd()) {
> - // Copy the current SCC and increment past it so that the pass can hack
> - // on the SCC if it wants to without invalidating our iterator.
> - const std::vector<CallGraphNode *> &NodeVec = *CGI;
> - CurSCC.initialize(NodeVec);
> - ++CGI;
> -
> - // At the top level, we run all the passes in this pass manager on the
> - // functions in this SCC. However, we support iterative compilation in the
> - // case where a function pass devirtualizes a call to a function. For
> - // example, it is very common for a function pass (often GVN or instcombine)
> - // to eliminate the addressing that feeds into a call. With that improved
> - // information, we would like the call to be an inline candidate, infer
> - // mod-ref information etc.
> - //
> - // Because of this, we allow iteration up to a specified iteration count.
> - // This only happens in the case of a devirtualized call, so we only burn
> - // compile time in the case that we're making progress. We also have a hard
> - // iteration count limit in case there is crazy code.
> - unsigned Iteration = 0;
> - bool DevirtualizedCall = false;
> - do {
> - LLVM_DEBUG(if (Iteration) dbgs()
> - << " SCCPASSMGR: Re-visiting SCC, iteration #" << Iteration
> - << '\n');
> - DevirtualizedCall = false;
> - Changed |= RunAllPassesOnSCC(CurSCC, CG, DevirtualizedCall);
> - } while (Iteration++ < MaxIterations && DevirtualizedCall);
> -
> - if (DevirtualizedCall)
> - LLVM_DEBUG(dbgs() << " CGSCCPASSMGR: Stopped iteration after "
> - << Iteration
> - << " times, due to -max-cg-scc-iterations\n");
> + DenseSet<const Function *> Visited;
>
> - MaxSCCIterations.updateMax(Iteration);
> + CallGraph::iterator INext;
> + for (auto I = CG.begin(), E = CG.end(); I != E;) {
> + // Walk the callgraph in bottom-up SCC order.
> + auto CGI = scc_begin<CallGraph *>(I->second.get());
> +
> + CallGraphSCC CurSCC(CG, &CGI);
> + while (!CGI.isAtEnd()) {
> + const std::vector<CallGraphNode *> &NodeVec = *CGI;
> +
> + // Record that we've seen this set of functions so we don't run the pass
> + // twice.
> + for (auto *Elt : NodeVec)
> + Visited.insert(Elt->getFunction());
> +
> + // Copy the current SCC and increment past it so that the pass can hack
> + // on the SCC if it wants to without invalidating our iterator.
> + CurSCC.initialize(NodeVec);
> + ++CGI;
> +
> + // If we've got all functions reachable from our chosen initial node,
> + // calculate the next node we need to search from now before parts of the
> + // graph are invalidated.
> + if (CGI.isAtEnd()) {
> + do
> + ++I;
> + while (I != E && Visited.count(I->first));
> + }
> +
> + Changed |= runOnSCC(CurSCC, CG);
> + }
> }
> +
> Changed |= doFinalization(CG);
> return Changed;
> }
>
> +bool CGPassManager::runOnSCC(CallGraphSCC &CurSCC, CallGraph &CG) {
> + bool Changed = false;
> +
> + // At the top level, we run all the passes in this pass manager on the
> + // functions in this SCC. However, we support iterative compilation in the
> + // case where a function pass devirtualizes a call to a function. For
> + // example, it is very common for a function pass (often GVN or instcombine)
> + // to eliminate the addressing that feeds into a call. With that improved
> + // information, we would like the call to be an inline candidate, infer
> + // mod-ref information etc.
> + //
> + // Because of this, we allow iteration up to a specified iteration count.
> + // This only happens in the case of a devirtualized call, so we only burn
> + // compile time in the case that we're making progress. We also have a hard
> + // iteration count limit in case there is crazy code.
> + unsigned Iteration = 0;
> + bool DevirtualizedCall = false;
> + do {
> + LLVM_DEBUG(if (Iteration) dbgs()
> + << " SCCPASSMGR: Re-visiting SCC, iteration #" << Iteration
> + << '\n');
> + DevirtualizedCall = false;
> + Changed |= RunAllPassesOnSCC(CurSCC, CG, DevirtualizedCall);
> + } while (Iteration++ < MaxIterations && DevirtualizedCall);
> +
> + if (DevirtualizedCall)
> + LLVM_DEBUG(dbgs() << " CGSCCPASSMGR: Stopped iteration after " << Iteration
> + << " times, due to -max-cg-scc-iterations\n");
> +
> + MaxSCCIterations.updateMax(Iteration);
> + return Changed;
> +}
> +
> /// Initialize CG
> bool CGPassManager::doInitialization(CallGraph &CG) {
> bool Changed = false;
>
> Modified: llvm/trunk/test/Transforms/Inline/always-inline.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Inline/always-inline.ll?rev=336419&r1=336418&r2=336419&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/Inline/always-inline.ll (original)
> +++ llvm/trunk/test/Transforms/Inline/always-inline.ll Fri Jul 6 01:04:47 2018
> @@ -316,3 +316,10 @@ define void @outer14() {
> call void @inner14()
> ret void
> }
> +
> +define internal i32 @outer15() {
> +; CHECK-LABEL: @outer15
> +; CHECK: ret i32 1
> + %res = call i32 @inner1()
> + ret i32 %res
> +}
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
-------------- next part --------------
@g_280 = external global i32
define i32 @func_1() {
bb1:
%l_55.115 = alloca i32*
%_tmp555 = load i32*, i32** %l_55.115
%_tmp565 = call i64 @func_27(i32* %_tmp555, i32* undef)
ret i32 undef
}
define internal i64 @func_27(i32* %p1, i32* %p2) !dbg !8 {
store i32* %p1, i32** undef
store i32* @g_280, i32** undef
ret i64 undef
}
define i16 @func_28() {
%_tmp5791 = call i32 @func_1()
ret i16 undef
}
!llvm.dbg.cu = !{}
!llvm.module.flags = !{!0}
!0 = !{i32 2, !"Debug Info Version", i32 3}
!1 = distinct !DISubprogram(name: "func_1", scope: !2, file: !2, line: 119, type: !3, isLocal: true, isDefinition: true, scopeLine: 120, isOptimized: false, unit: !5)
!2 = !DIFile(filename: "foo.c", directory: "/bar")
!3 = !DISubroutineType(types: !4)
!4 = !{}
!5 = distinct !DICompileUnit(language: DW_LANG_C, file: !2, producer: "My compiler", isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly)
!8 = distinct !DISubprogram(name: "func_27", scope: !2, file: !2, line: 251, type: !3, isLocal: true, isDefinition: true, scopeLine: 252, isOptimized: false, unit: !5)
More information about the llvm-commits
mailing list