[Clang] Invoke pass plugin preCodeGenCallback

[aengelke]

Single-use AddEmitPasses is inlined into RunCodegenPipeline for clarity
in comparing the parameters to the plugin and the parameters passed to
addPassesToEmitFile.

[llvmbot]

@llvm/pr-subscribers-clang-codegen

@llvm/pr-subscribers-clang

Author: Alexis Engelke (aengelke)

Changes

Single-use AddEmitPasses is inlined into RunCodegenPipeline for clarity
in comparing the parameters to the plugin and the parameters passed to
addPassesToEmitFile.

---

Full diff: https://github.com/llvm/llvm-project/pull/171872.diff

2 Files Affected:

• (modified) clang/lib/CodeGen/BackendUtil.cpp (+35-50)
• (added) clang/test/CodeGen/codegen-plugins.c (+14)

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index b39e303d13994..a5449d6c42e36 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -170,12 +170,6 @@ class EmitAssemblyHelper {
   /// the requested target.
   void CreateTargetMachine(bool MustCreateTM);
 
-  /// Add passes necessary to emit assembly or LLVM IR.
-  ///
-  /// \return True on success.
-  bool AddEmitPasses(legacy::PassManager &CodeGenPasses, BackendAction Action,
-                     raw_pwrite_stream &OS, raw_pwrite_stream *DwoOS);
-
   std::unique_ptr<llvm::ToolOutputFile> openOutputFile(StringRef Path) {
     std::error_code EC;
     auto F = std::make_unique<llvm::ToolOutputFile>(Path, EC,
@@ -647,33 +641,6 @@ void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
     TM->setLargeDataThreshold(CodeGenOpts.LargeDataThreshold);
 }
 
-bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
-                                       BackendAction Action,
-                                       raw_pwrite_stream &OS,
-                                       raw_pwrite_stream *DwoOS) {
-  // Add LibraryInfo.
-  std::unique_ptr<TargetLibraryInfoImpl> TLII(
-      llvm::driver::createTLII(TargetTriple, CodeGenOpts.getVecLib()));
-  CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
-
-  const llvm::TargetOptions &Options = TM->Options;
-  CodeGenPasses.add(new RuntimeLibraryInfoWrapper(
-      TargetTriple, Options.ExceptionModel, Options.FloatABIType,
-      Options.EABIVersion, Options.MCOptions.ABIName, Options.VecLib));
-
-  // Normal mode, emit a .s or .o file by running the code generator. Note,
-  // this also adds codegenerator level optimization passes.
-  CodeGenFileType CGFT = getCodeGenFileType(Action);
-
-  if (TM->addPassesToEmitFile(CodeGenPasses, OS, DwoOS, CGFT,
-                              /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
-    Diags.Report(diag::err_fe_unable_to_interface_with_target);
-    return false;
-  }
-
-  return true;
-}
-
 static OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
   switch (Opts.OptimizationLevel) {
   default:
@@ -1258,29 +1225,47 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
 void EmitAssemblyHelper::RunCodegenPipeline(
     BackendAction Action, std::unique_ptr<raw_pwrite_stream> &OS,
     std::unique_ptr<llvm::ToolOutputFile> &DwoOS) {
+  if (!actionRequiresCodeGen(Action))
+    return;
+
+  // Normal mode, emit a .s or .o file by running the code generator. Note,
+  // this also adds codegenerator level optimization passes.
+  CodeGenFileType CGFT = getCodeGenFileType(Action);
+
+  // Invoke pre-codegen callback from plugin, which might want to take over the
+  // entire code generation itself.
+  for (auto &Plugin : CodeGenOpts.PassPlugins) {
+    if (Plugin.invokePreCodeGenCallback(*TheModule, *TM, CGFT, *OS))
+      return;
+  }
+
   // We still use the legacy PM to run the codegen pipeline since the new PM
   // does not work with the codegen pipeline.
   // FIXME: make the new PM work with the codegen pipeline.
   legacy::PassManager CodeGenPasses;
 
-  // Append any output we need to the pass manager.
-  switch (Action) {
-  case Backend_EmitAssembly:
-  case Backend_EmitMCNull:
-  case Backend_EmitObj:
-    CodeGenPasses.add(
-        createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
-    if (!CodeGenOpts.SplitDwarfOutput.empty()) {
-      DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
-      if (!DwoOS)
-        return;
-    }
-    if (!AddEmitPasses(CodeGenPasses, Action, *OS,
-                       DwoOS ? &DwoOS->os() : nullptr))
-      // FIXME: Should we handle this error differently?
+  CodeGenPasses.add(
+      createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
+  // Add LibraryInfo.
+  std::unique_ptr<TargetLibraryInfoImpl> TLII(
+      llvm::driver::createTLII(TargetTriple, CodeGenOpts.getVecLib()));
+  CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
+
+  const llvm::TargetOptions &Options = TM->Options;
+  CodeGenPasses.add(new RuntimeLibraryInfoWrapper(
+      TargetTriple, Options.ExceptionModel, Options.FloatABIType,
+      Options.EABIVersion, Options.MCOptions.ABIName, Options.VecLib));
+
+  if (!CodeGenOpts.SplitDwarfOutput.empty()) {
+    DwoOS = openOutputFile(CodeGenOpts.SplitDwarfOutput);
+    if (!DwoOS)
       return;
-    break;
-  default:
+  }
+
+  if (TM->addPassesToEmitFile(CodeGenPasses, *OS,
+                              DwoOS ? &DwoOS->os() : nullptr, CGFT,
+                              /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
+    Diags.Report(diag::err_fe_unable_to_interface_with_target);
     return;
   }
 
diff --git a/clang/test/CodeGen/codegen-plugins.c b/clang/test/CodeGen/codegen-plugins.c
new file mode 100644
index 0000000000000..2e5fa5786e1c0
--- /dev/null
+++ b/clang/test/CodeGen/codegen-plugins.c
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -S < %s -fpass-plugin=%llvmshlibdir/Bye%pluginext 2>&1 | FileCheck %s --check-prefix=CHECK-INACTIVE
+// RUN: %clang_cc1 -S < %s -fpass-plugin=%llvmshlibdir/Bye%pluginext -mllvm -last-words 2>&1 | FileCheck %s --check-prefix=CHECK-ACTIVE
+// RUN: %clang_cc1 -emit-llvm < %s -fpass-plugin=%llvmshlibdir/Bye%pluginext -mllvm -last-words 2>&1 | FileCheck %s --check-prefix=CHECK-LLVM
+// RUN: not %clang_cc1 -emit-obj < %s -fpass-plugin=%llvmshlibdir/Bye%pluginext -mllvm -last-words 2>&1 | FileCheck %s --check-prefix=CHECK-ERR
+// REQUIRES: plugins, llvm-examples
+// UNSUPPORTED: target={{.*windows.*}}
+// CHECK-INACTIVE-NOT: Bye
+// CHECK-ACTIVE: Bye
+// CHECK-LLVM: define{{.*}} i32 @f
+// CHECK-ERR: error: last words unsupported for binary output
+
+int f(int x) {
+  return x;
+}

[github-actions]

🐧 Linux x64 Test Results

• 112221 tests passed
• 4533 tests skipped

✅ The build succeeded and all tests passed.

[vgvassilev]

Looks like we are heading in a good direction! Thank you, lgtm (assuming the bots are happy).

[aengelke]

Thanks. The code-formatter bot problem seems to be a network issue, no relation. Will land after #171868 (on which this depends).

[grigornik]

Hi
On clang-ppc64-aix test cases:

Clang::codegen-plugins.c (PR https://github.com/llvm/llvm-project/pull/171872)
Clang::pass-plugins.c (PR https://github.com/llvm/llvm-project/pull/173287)

fail on AIX https://lab.llvm.org/buildbot/#/builders/64/builds/6924
in similar way as LLVM::codegen-plugin.ll
https://lab.llvm.org/buildbot/#/builders/64/builds/6827/steps/6/logs/FAIL__LLVM__codegen-plugin_ll

With commit https://github.ibm.com/compiler/llvm-project/commit/f24c0ec4124e76e072200377a40c80f974cfb51f
you have xfailed codegen-plugin.ll
Can you please do same for

Clang::codegen-plugins.c
Clang::pass-plugins.c

From our side we will try to look at the original codegen-plugin.ll failure on AIX

[aengelke]

@grigornik Done with ad2c2b2. There's also #174006, in which I now also marked the tests as xfail on AIX.

I opened #172203 to track this issue..