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[RFC,v1,21/43] helper-to-tcg: Introduce PrepareForTcgPass

Message ID 20241121014947.18666-22-anjo@rev.ng (mailing list archive)
State New
Headers show
Series Introduce helper-to-tcg | expand

Commit Message

Anton Johansson Nov. 21, 2024, 1:49 a.m. UTC
Adds a new pass over the LLVM module which runs post-optimization with
the end-goal of:
  * culling functions which aren't worth translating;
  * canonicalizing the IR to something closer to TCG, and;
  * extracting information which may be useful in the backend pass.

This commits sets up a new LLVM pass over the IR module and runs it from
the pipeline.

Signed-off-by: Anton Johansson <anjo@rev.ng>
---
 .../helper-to-tcg/include/CmdLineOptions.h    |  2 ++
 .../helper-to-tcg/include/PrepareForTcgPass.h | 27 +++++++++++++++++++
 subprojects/helper-to-tcg/meson.build         |  1 +
 .../PrepareForTcgPass/PrepareForTcgPass.cpp   | 25 +++++++++++++++++
 .../helper-to-tcg/pipeline/Pipeline.cpp       | 26 +++++++++++++++++-
 5 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 subprojects/helper-to-tcg/include/PrepareForTcgPass.h
 create mode 100644 subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForTcgPass.cpp
diff mbox series

Patch

diff --git a/subprojects/helper-to-tcg/include/CmdLineOptions.h b/subprojects/helper-to-tcg/include/CmdLineOptions.h
index ed60c45f9a..9553e26407 100644
--- a/subprojects/helper-to-tcg/include/CmdLineOptions.h
+++ b/subprojects/helper-to-tcg/include/CmdLineOptions.h
@@ -23,3 +23,5 @@ 
 extern llvm::cl::list<std::string> InputFiles;
 // Options for PrepareForOptPass
 extern llvm::cl::opt<bool> TranslateAllHelpers;
+// Options for PrepareForTcgPass
+extern llvm::cl::opt<std::string> TcgGlobalMappingsName;
diff --git a/subprojects/helper-to-tcg/include/PrepareForTcgPass.h b/subprojects/helper-to-tcg/include/PrepareForTcgPass.h
new file mode 100644
index 0000000000..a41edb4c2e
--- /dev/null
+++ b/subprojects/helper-to-tcg/include/PrepareForTcgPass.h
@@ -0,0 +1,27 @@ 
+//
+//  Copyright(c) 2024 rev.ng Labs Srl. All Rights Reserved.
+//
+//  This program is free software; you can redistribute it and/or modify
+//  it under the terms of the GNU General Public License as published by
+//  the Free Software Foundation; either version 2 of the License, or
+//  (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+//
+//  You should have received a copy of the GNU General Public License
+//  along with this program; if not, see <http://www.gnu.org/licenses/>.
+//
+
+#pragma once
+
+#include <llvm/IR/PassManager.h>
+
+class PrepareForTcgPass : public llvm::PassInfoMixin<PrepareForTcgPass> {
+public:
+    PrepareForTcgPass() {}
+    llvm::PreservedAnalyses run(llvm::Module &M,
+                                llvm::ModuleAnalysisManager &MAM);
+};
diff --git a/subprojects/helper-to-tcg/meson.build b/subprojects/helper-to-tcg/meson.build
index 6aba71d5ca..6db1a019ce 100644
--- a/subprojects/helper-to-tcg/meson.build
+++ b/subprojects/helper-to-tcg/meson.build
@@ -46,6 +46,7 @@  sources = [
     'pipeline/Pipeline.cpp',
     'passes/PrepareForOptPass/PrepareForOptPass.cpp',
     'passes/PseudoInst.cpp',
+    'passes/PrepareForTcgPass/PrepareForTcgPass.cpp',
 ]
 
 clang = bindir / 'clang'
diff --git a/subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForTcgPass.cpp b/subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForTcgPass.cpp
new file mode 100644
index 0000000000..f0ef1abd17
--- /dev/null
+++ b/subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForTcgPass.cpp
@@ -0,0 +1,25 @@ 
+//
+//  Copyright(c) 2024 rev.ng Labs Srl. All Rights Reserved.
+//
+//  This program is free software; you can redistribute it and/or modify
+//  it under the terms of the GNU General Public License as published by
+//  the Free Software Foundation; either version 2 of the License, or
+//  (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+//
+//  You should have received a copy of the GNU General Public License
+//  along with this program; if not, see <http://www.gnu.org/licenses/>.
+//
+
+#include <PrepareForTcgPass.h>
+
+using namespace llvm;
+
+PreservedAnalyses PrepareForTcgPass::run(Module &M, ModuleAnalysisManager &MAM)
+{
+    return PreservedAnalyses::none();
+}
diff --git a/subprojects/helper-to-tcg/pipeline/Pipeline.cpp b/subprojects/helper-to-tcg/pipeline/Pipeline.cpp
index a26b7a7350..7d03389439 100644
--- a/subprojects/helper-to-tcg/pipeline/Pipeline.cpp
+++ b/subprojects/helper-to-tcg/pipeline/Pipeline.cpp
@@ -24,6 +24,7 @@ 
 #include <llvm/IR/LLVMContext.h>
 #include <llvm/IR/Module.h>
 #include <llvm/IR/PassManager.h>
+#include <llvm/IR/Verifier.h>
 #include <llvm/IRReader/IRReader.h>
 #include <llvm/InitializePasses.h>
 #include <llvm/Linker/Linker.h>
@@ -34,10 +35,12 @@ 
 #include <llvm/Support/SourceMgr.h>
 #include <llvm/Support/TargetSelect.h>
 #include <llvm/Target/TargetMachine.h>
+#include <llvm/Transforms/Scalar/DCE.h>
 #include <llvm/Transforms/Scalar/SROA.h>
 
 #include <PrepareForOptPass.h>
-#include "llvm-compat.h"
+#include <PrepareForTcgPass.h>
+#include <llvm-compat.h>
 
 using namespace llvm;
 
@@ -52,6 +55,13 @@  cl::opt<bool> TranslateAllHelpers(
     "translate-all-helpers", cl::init(false),
     cl::desc("Translate all functions starting with helper_*"), cl::cat(Cat));
 
+// Options for PrepareForTcgPass
+cl::opt<std::string> TcgGlobalMappingsName(
+    "tcg-global-mappings",
+    cl::desc("<Name of global cpu_mappings[] used for mapping accesses"
+             "into a struct to TCG globals>"),
+    cl::Required, cl::cat(Cat));
+
 // Define a TargetTransformInfo (TTI) subclass, this allows for overriding
 // common per-llvm-target information expected by other LLVM passes, such
 // as the width of the largest scalar/vector registers.  Needed for consistent
@@ -200,5 +210,19 @@  int main(int argc, char **argv)
     MPM.addPass(
         PB.buildModuleOptimizationPipeline(compat::OptimizationLevel::Os));
 
+    //
+    // Next, we run our final transformations, including removing phis and our
+    // own instruction combining that prioritizes instructions that map more
+    // easily to TCG.
+    //
+
+    MPM.addPass(PrepareForTcgPass());
+    MPM.addPass(VerifierPass());
+    {
+        FunctionPassManager FPM;
+        FPM.addPass(DCEPass());
+        MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
+    }
+
     return 0;
 }