[llvm] machinebackend pass test (PR #122487)
Kun Liu via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 10 18:05:54 PST 2025
https://github.com/Ryan-hub-bit updated https://github.com/llvm/llvm-project/pull/122487
>From 9e95cde15ce30630e7118fe046b6dff2d7adf7d9 Mon Sep 17 00:00:00 2001
From: Liu <kliu14 at tulane.edu>
Date: Fri, 10 Jan 2025 10:21:22 -0600
Subject: [PATCH 1/3] machinebackend pass test
---
llvm/lib/Target/X86/X86MatchJumptablePass.cpp | 44 +++++++++++++++++++
llvm/lib/Target/X86/X86MatchJumptablePass.h | 0
2 files changed, 44 insertions(+)
create mode 100644 llvm/lib/Target/X86/X86MatchJumptablePass.cpp
create mode 100644 llvm/lib/Target/X86/X86MatchJumptablePass.h
diff --git a/llvm/lib/Target/X86/X86MatchJumptablePass.cpp b/llvm/lib/Target/X86/X86MatchJumptablePass.cpp
new file mode 100644
index 00000000000000..bfb6b1b7f89f18
--- /dev/null
+++ b/llvm/lib/Target/X86/X86MatchJumptablePass.cpp
@@ -0,0 +1,44 @@
+#include "X86.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+
+
+using namespace llvm;
+
+namespace {
+ class X86MatchJumptablePass : public MachineFunctionPass {
+ public:
+ static char ID;
+
+ X86MatchJumptablePass() : MachineFunctionPass(ID) {}
+
+ bool runOnMachineFunction(MachineFunction &MF) override {
+ LLVM_DEBUG(dbgs() << "Running X86MyBackendPass on function: "
+ << MF.getName() << "\n");
+
+ // Example: Iterate through instructions
+ for (auto &MBB : MF) {
+ for (auto &MI : MBB) {
+ // Process instructions here
+ LLVM_DEBUG(dbgs() << "Instruction: " << MI << "\n");
+ }
+ }
+
+ return false; // Return true if the pass modifies the function
+ }
+
+ StringRef getPassName() const override {
+ return "X86 My Backend Pass";
+ }
+ };
+}
+
+char X86MatchJumptablePass::ID = 0;
+
+// Register the pass
+FunctionPass *llvm::createX86MatchJumptablePass() {
+ return new X86MatchJumptablePass();
+}
diff --git a/llvm/lib/Target/X86/X86MatchJumptablePass.h b/llvm/lib/Target/X86/X86MatchJumptablePass.h
new file mode 100644
index 00000000000000..e69de29bb2d1d6
>From 27bee8dbc8fa03e331302e799429b7450c2b1166 Mon Sep 17 00:00:00 2001
From: ryan <liu864579887 at gmail.com>
Date: Fri, 10 Jan 2025 17:01:39 -0600
Subject: [PATCH 2/3] good
---
.../llvm/Transforms/IPO/JumpTableFinder.h | 62 +++++++++++++++++++
llvm/lib/Target/X86/CMakeLists.txt | 1 +
llvm/lib/Target/X86/X86MatchJumptablePass.cpp | 15 +++--
llvm/lib/Target/X86/X86MatchJumptablePass.h | 14 +++++
llvm/lib/Target/X86/X86TargetMachine.cpp | 3 +-
5 files changed, 90 insertions(+), 5 deletions(-)
create mode 100644 llvm/include/llvm/Transforms/IPO/JumpTableFinder.h
diff --git a/llvm/include/llvm/Transforms/IPO/JumpTableFinder.h b/llvm/include/llvm/Transforms/IPO/JumpTableFinder.h
new file mode 100644
index 00000000000000..9d2fb3b405f8c8
--- /dev/null
+++ b/llvm/include/llvm/Transforms/IPO/JumpTableFinder.h
@@ -0,0 +1,62 @@
+// #ifndef LLVM_ANALYSIS_JUMPTABLEFINDERPASS_H
+// #define LLVM_ANALYSIS_JUMPTABLEFINDERPASS_H
+
+// #include "llvm/IR/PassManager.h"
+// #include "llvm/IR/Module.h"
+// #include "llvm/Support/raw_ostream.h"
+// #include <set>
+
+// namespace llvm {
+
+// class JumptableFinderPass : public PassInfoMixin<JumptableFinderPass> {
+// public:
+// /// Main entry point for the pass. Analyzes the module to find and analyze jump tables.
+// PreservedAnalyses run(Module &M, ModuleAnalysisManager &MAM);
+// /// Implementation of the jump table finder.
+// void jumptableFinderImpl(Module &M);
+
+// /// Analyze a SwitchInst for potential jump table patterns.
+// void findJumpTableFromSwitch(SwitchInst *SI);
+
+// /// Analyze a GetElementPtrInst for jump table patterns.
+// void analyzeJumpTable(GetElementPtrInst *GEP);
+
+// /// Analyze the index computation of a jump table.
+// void analyzeIndex(Value *Index);
+
+// /// Find all potential targets for a jump table.
+// void findTargets(GetElementPtrInst *GEP, std::set<BasicBlock*> &Targets);
+
+// /// Check the density of a SwitchInst's cases to determine if it forms a jump table.
+// bool checkDensity(SwitchInst *SI);
+
+// /// Check if a GetElementPtrInst leads to an indirect branch.
+// bool leadsToIndirectBranch(GetElementPtrInst *GEP);
+// };
+
+// } // namespace llvm
+
+// #endif // LLVM_ANALYSIS_JUMPTABLEFINDERPASS_H
+
+#ifndef LLVM_TRANSFORMS_IPO_JUMPTABLEFINDER_H
+#define LLVM_TRANSFORMS_IPO_JUMPTABLEFINDER_H
+
+#include "llvm/IR/Module.h"
+#include "llvm/IR/PassManager.h" // For PassInfoMixin and PreservedAnalyses
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/Support/raw_ostream.h"
+#include <set>
+
+namespace llvm {
+
+class JumptableFinderPass : public PassInfoMixin<JumptableFinderPass> {
+public:
+ // Entry point for the pass
+ PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
+};
+
+} // namespace llvm
+
+#endif // LLVM_TRANSFORMS_IPO_JUMPTABLEFINDER_H
diff --git a/llvm/lib/Target/X86/CMakeLists.txt b/llvm/lib/Target/X86/CMakeLists.txt
index 9553a8619feb51..4be4576a6a9057 100644
--- a/llvm/lib/Target/X86/CMakeLists.txt
+++ b/llvm/lib/Target/X86/CMakeLists.txt
@@ -23,6 +23,7 @@ tablegen(LLVM X86GenFoldTables.inc -gen-x86-fold-tables -asmwriternum=1)
add_public_tablegen_target(X86CommonTableGen)
set(sources
+X86MatchJumptablePass.cpp
X86ArgumentStackSlotRebase.cpp
X86AsmPrinter.cpp
X86AvoidTrailingCall.cpp
diff --git a/llvm/lib/Target/X86/X86MatchJumptablePass.cpp b/llvm/lib/Target/X86/X86MatchJumptablePass.cpp
index bfb6b1b7f89f18..c3683dacbdf8fe 100644
--- a/llvm/lib/Target/X86/X86MatchJumptablePass.cpp
+++ b/llvm/lib/Target/X86/X86MatchJumptablePass.cpp
@@ -4,7 +4,9 @@
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
+#include "X86MatchJumptablePass.h"
+#define DEBUG_TYPE "x86-my-pass"
using namespace llvm;
@@ -38,7 +40,12 @@ namespace {
char X86MatchJumptablePass::ID = 0;
-// Register the pass
-FunctionPass *llvm::createX86MatchJumptablePass() {
- return new X86MatchJumptablePass();
-}
+// Ensure the function is in the llvm namespace
+namespace llvm {
+
+ // Define the pass
+ FunctionPass *createX86MatchJumptablePass() {
+ return new X86MatchJumptablePass();
+ }
+
+} // end llvm namespace
diff --git a/llvm/lib/Target/X86/X86MatchJumptablePass.h b/llvm/lib/Target/X86/X86MatchJumptablePass.h
index e69de29bb2d1d6..67233bf729aec6 100644
--- a/llvm/lib/Target/X86/X86MatchJumptablePass.h
+++ b/llvm/lib/Target/X86/X86MatchJumptablePass.h
@@ -0,0 +1,14 @@
+#ifndef LLVM_LIB_TARGET_X86_X86MATCHJUMPTABLEPASS_H
+#define LLVM_LIB_TARGET_X86_X86MATCHJUMPTABLEPASS_H
+
+
+#pragma once
+#include "llvm/CodeGen/MachineFunctionPass.h"
+
+namespace llvm {
+
+ FunctionPass *createX86MatchJumptablePass();
+
+} // end namespace llvm
+
+#endif // LLVM_LIB_TARGET_X86_X86MATCHJUMPTABLEPASS_H
\ No newline at end of file
diff --git a/llvm/lib/Target/X86/X86TargetMachine.cpp b/llvm/lib/Target/X86/X86TargetMachine.cpp
index 20dfdd27b33df6..b9c13fda07dfc7 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.cpp
+++ b/llvm/lib/Target/X86/X86TargetMachine.cpp
@@ -12,6 +12,7 @@
#include "X86TargetMachine.h"
#include "MCTargetDesc/X86MCTargetDesc.h"
+#include "X86MatchJumptablePass.h" // Include the header with the function declaration
#include "TargetInfo/X86TargetInfo.h"
#include "X86.h"
#include "X86MachineFunctionInfo.h"
@@ -464,7 +465,7 @@ MachineFunctionInfo *X86TargetMachine::createMachineFunctionInfo(
void X86PassConfig::addIRPasses() {
addPass(createAtomicExpandLegacyPass());
-
+ addPass(llvm::createX86MatchJumptablePass());
// We add both pass anyway and when these two passes run, we skip the pass
// based on the option level and option attribute.
addPass(createX86LowerAMXIntrinsicsPass());
>From 0dc2ceac51b6c4182a8816b215146b3b7a68c1bd Mon Sep 17 00:00:00 2001
From: Liu <kliu14 at tulane.edu>
Date: Fri, 10 Jan 2025 20:05:42 -0600
Subject: [PATCH 3/3] jumptable
---
llvm/lib/Target/X86/CMakeLists.txt | 2 +-
llvm/lib/Target/X86/X86MatchJumptablePass.cpp | 102 +++++++++++++++---
llvm/lib/Target/X86/X86MatchJumptablePass.h | 10 +-
llvm/lib/Target/X86/X86TargetMachine.cpp | 5 +-
4 files changed, 99 insertions(+), 20 deletions(-)
diff --git a/llvm/lib/Target/X86/CMakeLists.txt b/llvm/lib/Target/X86/CMakeLists.txt
index 4be4576a6a9057..f5dcf13e47ed25 100644
--- a/llvm/lib/Target/X86/CMakeLists.txt
+++ b/llvm/lib/Target/X86/CMakeLists.txt
@@ -23,7 +23,7 @@ tablegen(LLVM X86GenFoldTables.inc -gen-x86-fold-tables -asmwriternum=1)
add_public_tablegen_target(X86CommonTableGen)
set(sources
-X86MatchJumptablePass.cpp
+ X86MatchJumptablePass.cpp
X86ArgumentStackSlotRebase.cpp
X86AsmPrinter.cpp
X86AvoidTrailingCall.cpp
diff --git a/llvm/lib/Target/X86/X86MatchJumptablePass.cpp b/llvm/lib/Target/X86/X86MatchJumptablePass.cpp
index c3683dacbdf8fe..d8263af59a855d 100644
--- a/llvm/lib/Target/X86/X86MatchJumptablePass.cpp
+++ b/llvm/lib/Target/X86/X86MatchJumptablePass.cpp
@@ -6,7 +6,7 @@
#include "llvm/Support/raw_ostream.h"
#include "X86MatchJumptablePass.h"
-#define DEBUG_TYPE "x86-my-pass"
+#define DEBUG_TYPE "match-jump-table"
using namespace llvm;
@@ -18,23 +18,97 @@ namespace {
X86MatchJumptablePass() : MachineFunctionPass(ID) {}
bool runOnMachineFunction(MachineFunction &MF) override {
- LLVM_DEBUG(dbgs() << "Running X86MyBackendPass on function: "
- << MF.getName() << "\n");
-
- // Example: Iterate through instructions
- for (auto &MBB : MF) {
- for (auto &MI : MBB) {
- // Process instructions here
- LLVM_DEBUG(dbgs() << "Instruction: " << MI << "\n");
+ LLVM_DEBUG(dbgs() << "Analyzing jump tables in function: " << MF.getName() << "\n");
+
+ // Get jump table information
+ MachineJumpTableInfo *JumpTableInfo = MF.getJumpTableInfo();
+ if (!JumpTableInfo) {
+ LLVM_DEBUG(dbgs() << "No jump tables in this function.\n");
+ return false;
+ }
+ // Assuming JumpTableInfo is available
+ for (unsigned JTIndex = 0; JTIndex < JumpTableInfo->getJumpTables().size(); ++JTIndex) {
+ const MachineJumpTableEntry &JTEntry = JumpTableInfo->getJumpTables()[JTIndex];
+
+ LLVM_DEBUG(dbgs() << "Jump Table #" << JTIndex << " Base Address: " << JTEntry.BaseAddress << "\n");
+
+ // Iterate through the entries (target basic blocks) in this jump table
+ for (auto *MBB : JTEntry.MBBs) {
+ LLVM_DEBUG(dbgs() << " Target BasicBlock: " << MBB->getName() << " Address: " << MBB->getAddress() << "\n");
+ }
+
+
+ // Trace potential indirect jumps related to this jump table
+ traceIndirectJumps(MF, JTIndex, JumpTableInfo);
+ }
+ return false;
+
+}
+
+ void traceIndirectJumps(MachineFunction &MF, unsigned JTIndex, MachineJumpTableInfo *JumpTableInfo) {
+ const MachineJumpTableEntry &JTEntry = JumpTableInfo->getJumpTables()[JTIndex];
+
+ for (auto &MBB : MF) {
+ for (auto &MI : MBB) {
+ if (MI.isIndirectBranch()) {
+ LLVM_DEBUG(dbgs() << "Found indirect jump: " << MI << "\n");
+
+ // Analyze data flow to check if this jump is related to the jump table
+ if (isJumpTableRelated(MI, JTEntry, MF)) {
+ LLVM_DEBUG(dbgs() << "This indirect jump is related to Jump Table #" << JTIndex << "\n");
+ }
}
}
+ }
+ }
+
+ bool isJumpTableRelated(MachineInstr &MI, const MachineJumpTableEntry &JTEntry, MachineFunction &MF) {
+ for (unsigned OpIdx = 0; OpIdx < MI.getNumOperands(); ++OpIdx) {
+ const MachineOperand &Op = MI.getOperand(OpIdx);
- return false; // Return true if the pass modifies the function
+ if (Op.isReg()) {
+ Register Reg = Op.getReg();
+ MachineRegisterInfo &MRI = MF.getRegInfo();
+ // Check if any of the definitions of the register are related to a jump table load
+ for (MachineInstr &DefMI : MRI.def_instructions(Reg)) {
+ if (isJumpTableLoad(DefMI, JTEntry)) {
+ return true;
+ }
+ }
+ } else if (Op.isImm()) {
+ // Check if the immediate operand might be an offset/index into the jump table
+ int64_t ImmValue = Op.getImm();
+
+ // For example, if the jump table has 10 entries, check if the immediate is between 0 and 9
+ if (ImmValue >= 0 && ImmValue < JTEntry.MBBs.size()) {
+ // This immediate value could be an index into the jump table
+ LLVM_DEBUG(dbgs() << "Immediate operand is a possible jump table index: " << ImmValue << "\n");
+ return true;
+ }
}
+ }
+ return false;
+}
- StringRef getPassName() const override {
- return "X86 My Backend Pass";
+bool isJumpTableLoad(MachineInstr &MI, const MachineJumpTableEntry &JTEntry) {
+ if (MI.mayLoad()) {
+ for (unsigned i = 0; i < MI.getNumOperands(); ++i) {
+ const MachineOperand &Op = MI.getOperand(i);
+ if (Op.isGlobal() && Op.getGlobal() == JTEntry.BaseAddress) {
+ return true;
+ }
+ }
}
+ return false;
+}
+
+ StringRef getPassName() const override {
+ return "Match Jump Table Pass";
+ }
+
+ // StringRef getPassName() const override {
+ // return "X86 My Backend Pass";
+ // }
};
}
@@ -49,3 +123,7 @@ namespace llvm {
}
} // end llvm namespace
+
+static RegisterPass<X86MatchJumptablePass> X("match-jump-table", "Match Jump Table Pass", false, false);
+
+
diff --git a/llvm/lib/Target/X86/X86MatchJumptablePass.h b/llvm/lib/Target/X86/X86MatchJumptablePass.h
index 67233bf729aec6..ac6fc315b025ad 100644
--- a/llvm/lib/Target/X86/X86MatchJumptablePass.h
+++ b/llvm/lib/Target/X86/X86MatchJumptablePass.h
@@ -1,14 +1,14 @@
#ifndef LLVM_LIB_TARGET_X86_X86MATCHJUMPTABLEPASS_H
#define LLVM_LIB_TARGET_X86_X86MATCHJUMPTABLEPASS_H
-
-#pragma once
#include "llvm/CodeGen/MachineFunctionPass.h"
namespace llvm {
- FunctionPass *createX86MatchJumptablePass();
+/// \brief Creates the X86MatchJumptablePass.
+/// This pass analyzes and processes jump tables in X86 backend code generation.
+FunctionPass *createX86MatchJumptablePass();
-} // end namespace llvm
+} // namespace llvm
-#endif // LLVM_LIB_TARGET_X86_X86MATCHJUMPTABLEPASS_H
\ No newline at end of file
+#endif // LLVM_LIB_TARGET_X86_X86MATCHJUMPTABLEPASS_H
diff --git a/llvm/lib/Target/X86/X86TargetMachine.cpp b/llvm/lib/Target/X86/X86TargetMachine.cpp
index b9c13fda07dfc7..7faeeb2af64e8e 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.cpp
+++ b/llvm/lib/Target/X86/X86TargetMachine.cpp
@@ -11,8 +11,8 @@
//===----------------------------------------------------------------------===//
#include "X86TargetMachine.h"
+#include "X86MatchJumptablePass.h"
#include "MCTargetDesc/X86MCTargetDesc.h"
-#include "X86MatchJumptablePass.h" // Include the header with the function declaration
#include "TargetInfo/X86TargetInfo.h"
#include "X86.h"
#include "X86MachineFunctionInfo.h"
@@ -465,7 +465,7 @@ MachineFunctionInfo *X86TargetMachine::createMachineFunctionInfo(
void X86PassConfig::addIRPasses() {
addPass(createAtomicExpandLegacyPass());
- addPass(llvm::createX86MatchJumptablePass());
+
// We add both pass anyway and when these two passes run, we skip the pass
// based on the option level and option attribute.
addPass(createX86LowerAMXIntrinsicsPass());
@@ -597,6 +597,7 @@ void X86PassConfig::addPreEmitPass() {
addPass(createBreakFalseDeps());
}
+ addPass(createX86MatchJumptablePass());
addPass(createX86IndirectBranchTrackingPass());
addPass(createX86IssueVZeroUpperPass());
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