[llvm] r254774 - [llc/opt] Add an option to run all passes twice
Keno Fischer via llvm-commits
llvm-commits at lists.llvm.org
Fri Dec 4 13:56:47 PST 2015
Author: kfischer
Date: Fri Dec 4 15:56:46 2015
New Revision: 254774
URL: http://llvm.org/viewvc/llvm-project?rev=254774&view=rev
Log:
[llc/opt] Add an option to run all passes twice
Summary: Lately, I have submitted a number of patches to fix bugs that
only occurred when using the same pass manager to compile multiple
modules (generally these bugs are failure to reset some persistent
state). Unfortunately I don't think there is currently a way to test
that from the command line. This adds a very simple flag to both llc
and opt, under which the tools will simply re-run their respective
pass pipelines using the same pass manager on (a clone of the same
module). Additionally, we verify that both outputs are bitwise the
same.
Reviewers: yaron.keren
Subscribers: loladiro, yaron.keren, kcc, llvm-commits
Differential Revision: http://reviews.llvm.org/D14965
Added:
llvm/trunk/test/MC/ELF/empty-twice.ll
llvm/trunk/test/Other/opt-twice.ll
Modified:
llvm/trunk/tools/llc/llc.cpp
llvm/trunk/tools/opt/opt.cpp
Added: llvm/trunk/test/MC/ELF/empty-twice.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/empty-twice.ll?rev=254774&view=auto
==============================================================================
--- llvm/trunk/test/MC/ELF/empty-twice.ll (added)
+++ llvm/trunk/test/MC/ELF/empty-twice.ll Fri Dec 4 15:56:46 2015
@@ -0,0 +1,6 @@
+; Check that there is no persistent state in the ELF emitter that crashes us
+; when we try to reuse the pass manager
+; RUN: llc -compile-twice -filetype=obj %s -o -
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32"
+target triple = "i386-pc-linux-gnu"
Added: llvm/trunk/test/Other/opt-twice.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Other/opt-twice.ll?rev=254774&view=auto
==============================================================================
--- llvm/trunk/test/Other/opt-twice.ll (added)
+++ llvm/trunk/test/Other/opt-twice.ll Fri Dec 4 15:56:46 2015
@@ -0,0 +1,14 @@
+; The pass here doesn't matter (we use deadargelim), but test
+; that the -run-twice options exists, generates output, and
+; doesn't crash
+; RUN: opt -run-twice -deadargelim -S < %s | FileCheck %s
+
+; CHECK: define internal void @test
+define internal {} @test() {
+ ret {} undef
+}
+
+define void @caller() {
+ call {} @test()
+ ret void
+}
Modified: llvm/trunk/tools/llc/llc.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llc/llc.cpp?rev=254774&r1=254773&r2=254774&view=diff
==============================================================================
--- llvm/trunk/tools/llc/llc.cpp (original)
+++ llvm/trunk/tools/llc/llc.cpp Fri Dec 4 15:56:46 2015
@@ -45,6 +45,7 @@
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetSubtargetInfo.h"
+#include "llvm/Transforms/Utils/Cloning.h"
#include <memory>
using namespace llvm;
@@ -96,6 +97,12 @@ static cl::opt<bool> AsmVerbose("asm-ver
cl::desc("Add comments to directives."),
cl::init(true));
+static cl::opt<bool>
+ CompileTwice("compile-twice", cl::Hidden,
+ cl::desc("Run everything twice, re-using the same pass "
+ "manager and verify the the result is the same."),
+ cl::init(false));
+
static int compileModule(char **, LLVMContext &);
static std::unique_ptr<tool_output_file>
@@ -325,10 +332,15 @@ static int compileModule(char **argv, LL
{
raw_pwrite_stream *OS = &Out->os();
- std::unique_ptr<buffer_ostream> BOS;
- if (FileType != TargetMachine::CGFT_AssemblyFile &&
- !Out->os().supportsSeeking()) {
- BOS = make_unique<buffer_ostream>(*OS);
+
+ // Manually do the buffering rather than using buffer_ostream,
+ // so we can memcmp the contents in CompileTwice mode
+ SmallVector<char, 0> Buffer;
+ std::unique_ptr<raw_svector_ostream> BOS;
+ if ((FileType != TargetMachine::CGFT_AssemblyFile &&
+ !Out->os().supportsSeeking()) ||
+ CompileTwice) {
+ BOS = make_unique<raw_svector_ostream>(Buffer);
OS = BOS.get();
}
@@ -378,7 +390,39 @@ static int compileModule(char **argv, LL
// Before executing passes, print the final values of the LLVM options.
cl::PrintOptionValues();
+ // If requested, run the pass manager over the same module again,
+ // to catch any bugs due to persistent state in the passes. Note that
+ // opt has the same functionality, so it may be worth abstracting this out
+ // in the future.
+ SmallVector<char, 0> CompileTwiceBuffer;
+ if (CompileTwice) {
+ std::unique_ptr<Module> M2(llvm::CloneModule(M.get()));
+ PM.run(*M2);
+ CompileTwiceBuffer = Buffer;
+ Buffer.clear();
+ }
+
PM.run(*M);
+
+ // Compare the two outputs and make sure they're the same
+ if (CompileTwice) {
+ if (Buffer.size() != CompileTwiceBuffer.size() ||
+ (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) !=
+ 0)) {
+ errs()
+ << "Running the pass manager twice changed the output.\n"
+ "Writing the result of the second run to the specified output\n"
+ "To generate the one-run comparison binary, just run without\n"
+ "the compile-twice option\n";
+ Out->os() << Buffer;
+ Out->keep();
+ return 1;
+ }
+ }
+
+ if (BOS) {
+ Out->os() << Buffer;
+ }
}
// Declare success.
Modified: llvm/trunk/tools/opt/opt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/opt/opt.cpp?rev=254774&r1=254773&r2=254774&view=diff
==============================================================================
--- llvm/trunk/tools/opt/opt.cpp (original)
+++ llvm/trunk/tools/opt/opt.cpp Fri Dec 4 15:56:46 2015
@@ -28,6 +28,7 @@
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/IRPrintingPasses.h"
#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/LegacyPassNameParser.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
@@ -36,7 +37,6 @@
#include "llvm/LinkAllIR.h"
#include "llvm/LinkAllPasses.h"
#include "llvm/MC/SubtargetFeature.h"
-#include "llvm/IR/LegacyPassManager.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Host.h"
@@ -51,6 +51,7 @@
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/IPO/PassManagerBuilder.h"
+#include "llvm/Transforms/Utils/Cloning.h"
#include <algorithm>
#include <memory>
using namespace llvm;
@@ -190,6 +191,11 @@ static cl::opt<bool> PreserveAssemblyUse
cl::desc("Preserve use-list order when writing LLVM assembly."),
cl::init(false), cl::Hidden);
+static cl::opt<bool>
+ RunTwice("run-twice",
+ cl::desc("Run all passes twice, re-using the same pass manager."),
+ cl::init(false), cl::Hidden);
+
static inline void addPass(legacy::PassManagerBase &PM, Pass *P) {
// Add the pass to the pass manager...
PM.add(P);
@@ -582,14 +588,25 @@ int main(int argc, char **argv) {
if (!NoVerify && !VerifyEach)
Passes.add(createVerifierPass());
+ // In run twice mode, we want to make sure the output is bit-by-bit
+ // equivalent if we run the pass manager again, so setup two buffers and
+ // a stream to write to them. Note that llc does something similar and it
+ // may be worth to abstract this out in the future.
+ SmallVector<char, 0> Buffer;
+ SmallVector<char, 0> CompileTwiceBuffer;
+ std::unique_ptr<raw_svector_ostream> BOS;
+ raw_ostream *OS = &Out->os();
+ if (RunTwice) {
+ BOS = make_unique<raw_svector_ostream>(Buffer);
+ OS = BOS.get();
+ }
+
// Write bitcode or assembly to the output as the last step...
if (!NoOutput && !AnalyzeOnly) {
if (OutputAssembly)
- Passes.add(
- createPrintModulePass(Out->os(), "", PreserveAssemblyUseListOrder));
+ Passes.add(createPrintModulePass(*OS, "", PreserveAssemblyUseListOrder));
else
- Passes.add(
- createBitcodeWriterPass(Out->os(), PreserveBitcodeUseListOrder));
+ Passes.add(createBitcodeWriterPass(*OS, PreserveBitcodeUseListOrder));
}
// Before executing passes, print the final values of the LLVM options.
@@ -598,6 +615,27 @@ int main(int argc, char **argv) {
// Now that we have all of the passes ready, run them.
Passes.run(*M);
+ // If requested, run all passes again with the same pass manager to catch
+ // bugs caused by persistent state in the passes
+ if (RunTwice) {
+ CompileTwiceBuffer = Buffer;
+ Buffer.clear();
+ std::unique_ptr<Module> M2(CloneModule(M.get()));
+ Passes.run(*M2);
+ if (Buffer.size() != CompileTwiceBuffer.size() ||
+ (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) !=
+ 0)) {
+ errs() << "Running the pass manager twice changed the output.\n"
+ "Writing the result of the second run to the specified output."
+ "To generate the one-run comparison binary, just run without\n"
+ "the compile-twice option\n";
+ Out->os() << BOS->str();
+ Out->keep();
+ return 1;
+ }
+ Out->os() << BOS->str();
+ }
+
// Declare success.
if (!NoOutput || PrintBreakpoints)
Out->keep();
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