[llvm] e33c9bb - Flags for displaying only hot nodes in CFGPrinter graph
Artur Pilipenko via llvm-commits
llvm-commits at lists.llvm.org
Fri Feb 21 17:20:10 PST 2020
Author: Kirill Naumov
Date: 2020-02-21T17:20:00-08:00
New Revision: e33c9bb245a0c17cdd5c06897a911f908215db50
URL: https://github.com/llvm/llvm-project/commit/e33c9bb245a0c17cdd5c06897a911f908215db50
DIFF: https://github.com/llvm/llvm-project/commit/e33c9bb245a0c17cdd5c06897a911f908215db50.diff
LOG: Flags for displaying only hot nodes in CFGPrinter graph
Added two flags to omit uncommon or dead paths in the CFG graphs:
-cfg-hide-unreachable-paths
-cfg-hide-deoptimize-paths
The main purpose is performance analysis when such block are not
"interesting" from perspective of common path performance.
Reviewed By: apilipenko, davidxl
Differential Revision: https://reviews.llvm.org/D74346
Added:
llvm/test/Other/cfg_deopt_unreach.ll
Modified:
llvm/include/llvm/Analysis/CFGPrinter.h
llvm/lib/Analysis/CFGPrinter.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/Analysis/CFGPrinter.h b/llvm/include/llvm/Analysis/CFGPrinter.h
index aaefc11653dd..634be322a4a9 100644
--- a/llvm/include/llvm/Analysis/CFGPrinter.h
+++ b/llvm/include/llvm/Analysis/CFGPrinter.h
@@ -53,6 +53,9 @@ class CFGOnlyPrinterPass
template<>
struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
+ // Cache for is hidden property
+ llvm::DenseMap <const BasicBlock *, bool> isHiddenBasicBlock;
+
DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
static std::string getGraphName(const Function *F) {
@@ -173,6 +176,8 @@ struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
// profile count (due to scaling).
return ("label=\"W:" + Twine(Weight->getZExtValue()) + "\"").str();
}
+ bool isNodeHidden(const BasicBlock *Node);
+ void computeHiddenNodes(const Function *F);
};
} // End llvm namespace
diff --git a/llvm/lib/Analysis/CFGPrinter.cpp b/llvm/lib/Analysis/CFGPrinter.cpp
index 88e7d3bdede1..4a708b4981ae 100644
--- a/llvm/lib/Analysis/CFGPrinter.cpp
+++ b/llvm/lib/Analysis/CFGPrinter.cpp
@@ -17,11 +17,14 @@
//
//===----------------------------------------------------------------------===//
+#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/Analysis/CFGPrinter.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileSystem.h"
+#include <algorithm>
+
using namespace llvm;
static cl::opt<std::string> CFGFuncName(
@@ -33,6 +36,12 @@ static cl::opt<std::string> CFGDotFilenamePrefix(
"cfg-dot-filename-prefix", cl::Hidden,
cl::desc("The prefix used for the CFG dot file names."));
+static cl::opt<bool> HideUnreachablePaths("cfg-hide-unreachable-paths",
+ cl::init(false));
+
+static cl::opt<bool> HideDeoptimizePaths("cfg-hide-deoptimize-paths",
+ cl::init(false));
+
namespace {
struct CFGViewerLegacyPass : public FunctionPass {
static char ID; // Pass identifcation, replacement for typeid
@@ -200,3 +209,30 @@ FunctionPass *llvm::createCFGOnlyPrinterLegacyPassPass () {
return new CFGOnlyPrinterLegacyPass();
}
+void DOTGraphTraits<const Function *>::computeHiddenNodes(const Function *F) {
+ auto evaluateBB = [&](const BasicBlock *Node) {
+ if (succ_begin(Node) == succ_end(Node)) {
+ const Instruction *TI = Node->getTerminator();
+ isHiddenBasicBlock[Node] =
+ (HideUnreachablePaths && isa<UnreachableInst>(TI)) ||
+ (HideDeoptimizePaths && Node->getTerminatingDeoptimizeCall());
+ return;
+ }
+ isHiddenBasicBlock[Node] = std::all_of(
+ succ_begin(Node), succ_end(Node),
+ [this](const BasicBlock *BB) { return isHiddenBasicBlock[BB]; });
+ };
+ /// The post order traversal iteration is done to know the status of
+ /// isHiddenBasicBlock for all the successors on the current BB.
+ for_each(po_begin(&F->getEntryBlock()), po_end(&F->getEntryBlock()),
+ evaluateBB);
+}
+
+bool DOTGraphTraits<const Function *>::isNodeHidden(const BasicBlock *Node) {
+ // If both restricting flags are false, all nodes are displayed.
+ if (!HideUnreachablePaths && !HideDeoptimizePaths)
+ return false;
+ if (isHiddenBasicBlock.find(Node) == isHiddenBasicBlock.end())
+ computeHiddenNodes(Node->getParent());
+ return isHiddenBasicBlock[Node];
+}
diff --git a/llvm/test/Other/cfg_deopt_unreach.ll b/llvm/test/Other/cfg_deopt_unreach.ll
new file mode 100644
index 000000000000..25fae44ed250
--- /dev/null
+++ b/llvm/test/Other/cfg_deopt_unreach.ll
@@ -0,0 +1,33 @@
+; RUN: opt < %s -analyze -dot-cfg -cfg-hide-unreachable-paths -cfg-dot-filename-prefix=unreach 2>/dev/null
+; RUN: FileCheck %s -input-file=unreach.callee.dot -check-prefix=UNREACH
+; RUN: opt < %s -analyze -dot-cfg -cfg-hide-deoptimize-paths -cfg-dot-filename-prefix=deopt 2>/dev/null
+; RUN: FileCheck %s -input-file=deopt.callee.dot -check-prefix=DEOPT
+; RUN: opt < %s -analyze -dot-cfg -cfg-dot-filename-prefix=no-flags 2>/dev/null
+; RUN: FileCheck %s -input-file=no-flags.callee.dot -check-prefix=NO-FLAGS
+; RUN: opt < %s -analyze -dot-cfg -cfg-hide-unreachable-paths -cfg-hide-deoptimize-paths -cfg-dot-filename-prefix=both-flags 2>/dev/null
+; RUN: FileCheck %s -input-file=both-flags.callee.dot -check-prefix=BOTH-FLAGS
+
+declare i8 @llvm.experimental.deoptimize.i8(...)
+
+define i8 @callee(i1* %c) alwaysinline {
+; NO-FLAGS: [shape=record,label="{%0:\l %c0 = load volatile i1, i1* %c\l br i1 %c0, label %lleft, label %lright\l|{<s0>T|<s1>F}}"];
+; DEOPT: [shape=record,label="{%0:\l %c0 = load volatile i1, i1* %c\l br i1 %c0, label %lleft, label %lright\l|{<s0>T|<s1>F}}"];
+; UNREACH: [shape=record,label="{%0:\l %c0 = load volatile i1, i1* %c\l br i1 %c0, label %lleft, label %lright\l|{<s0>T|<s1>F}}"];
+; BOTH-FLAGS-NOT: [shape=record,label="{%0:\l %c0 = load volatile i1, i1* %c\l br i1 %c0, label %lleft, label %lright\l|{<s0>T|<s1>F}}"];
+ %c0 = load volatile i1, i1* %c
+ br i1 %c0, label %lleft, label %lright
+; NO-FLAGS: [shape=record,label="{lleft: \l %v0 = call i8 (...) @llvm.experimental.deoptimize.i8(i32 1) [ \"deopt\"(i32 1)\l... ]\l ret i8 %v0\l}"];
+; DEOPT-NOT: [shape=record,label="{lleft: \l %v0 = call i8 (...) @llvm.experimental.deoptimize.i8(i32 1) [ \"deopt\"(i32 1)\l... ]\l ret i8 %v0\l}"];
+; UNREACH: [shape=record,label="{lleft: \l %v0 = call i8 (...) @llvm.experimental.deoptimize.i8(i32 1) [ \"deopt\"(i32 1)\l... ]\l ret i8 %v0\l}"];
+; BOTH-FLAGS-NOT: [shape=record,label="{lleft: \l %v0 = call i8 (...) @llvm.experimental.deoptimize.i8(i32 1) [ \"deopt\"(i32 1)\l... ]\l ret i8 %v0\l}"];
+lleft:
+ %v0 = call i8(...) @llvm.experimental.deoptimize.i8(i32 1) [ "deopt"(i32 1) ]
+ ret i8 %v0
+
+; NO-FLAGS: [shape=record,label="{lright: \l unreachable\l}"];
+; DEOPT: [shape=record,label="{lright: \l unreachable\l}"];
+; UNREACH-NOT: [shape=record,label="{lright: \l unreachable\l}"];
+; BOTH-FLAGS-NOT: [shape=record,label="{lright: \l unreachable\l}"];
+lright:
+ unreachable
+}
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