[llvm] r333861 - [Debugify] Don't apply DI before the bitcode writer pass

[Vedant Kumar via llvm-commits]

Author: vedantk
Date: Sun Jun  3 17:11:49 2018
New Revision: 333861

URL: http://llvm.org/viewvc/llvm-project?rev=333861&view=rev
Log:
[Debugify] Don't apply DI before the bitcode writer pass

Applying synthetic debug info before the bitcode writer pass has no
testing-related purpose. This commit prevents that from happening.

It also adds tests which check that IR produced with/without
-debugify-each enabled is identical after stripping. This makes it
possible to check that individual passes (or full pipelines) are
invariant to debug info.

Modified:
    llvm/trunk/include/llvm/Bitcode/BitcodeWriterPass.h
    llvm/trunk/lib/Bitcode/Writer/BitcodeWriterPass.cpp
    llvm/trunk/test/DebugInfo/debugify-each.ll
    llvm/trunk/tools/opt/opt.cpp

Modified: llvm/trunk/include/llvm/Bitcode/BitcodeWriterPass.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Bitcode/BitcodeWriterPass.h?rev=333861&r1=333860&r2=333861&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Bitcode/BitcodeWriterPass.h (original)
+++ llvm/trunk/include/llvm/Bitcode/BitcodeWriterPass.h Sun Jun  3 17:11:49 2018
@@ -21,6 +21,7 @@
 namespace llvm {
 class Module;
 class ModulePass;
+class Pass;
 class raw_ostream;
 
 /// Create and return a pass that writes the module to the specified
@@ -40,6 +41,9 @@ ModulePass *createBitcodeWriterPass(raw_
                                     bool EmitSummaryIndex = false,
                                     bool EmitModuleHash = false);
 
+/// Check whether a pass is a BitcodeWriterPass.
+bool isBitcodeWriterPass(Pass *P);
+
 /// Pass for writing a module of IR out to a bitcode file.
 ///
 /// Note that this is intended for use with the new pass manager. To construct

Modified: llvm/trunk/lib/Bitcode/Writer/BitcodeWriterPass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Bitcode/Writer/BitcodeWriterPass.cpp?rev=333861&r1=333860&r2=333861&view=diff
==============================================================================
--- llvm/trunk/lib/Bitcode/Writer/BitcodeWriterPass.cpp (original)
+++ llvm/trunk/lib/Bitcode/Writer/BitcodeWriterPass.cpp Sun Jun  3 17:11:49 2018
@@ -80,3 +80,7 @@ ModulePass *llvm::createBitcodeWriterPas
   return new WriteBitcodePass(Str, ShouldPreserveUseListOrder,
                               EmitSummaryIndex, EmitModuleHash);
 }
+
+bool llvm::isBitcodeWriterPass(Pass *P) {
+  return P->getPassID() == (llvm::AnalysisID)&WriteBitcodePass::ID;
+}

Modified: llvm/trunk/test/DebugInfo/debugify-each.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/debugify-each.ll?rev=333861&r1=333860&r2=333861&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/debugify-each.ll (original)
+++ llvm/trunk/test/DebugInfo/debugify-each.ll Sun Jun  3 17:11:49 2018
@@ -13,7 +13,25 @@
 ; Verify that debugify each can be safely used with piping
 ; RUN: opt -debugify-each -O1 < %s | opt -O2 -o /dev/null
 
-define void @foo() {
+; Check that stripped textual IR compares equal before and after applying
+; debugify.
+; RUN: opt -O1 < %s -S -o - | \
+; RUN:   opt -strip -strip-dead-prototypes -strip-module-flags -S -o %t.before
+; RUN: opt -O1 -debugify-each < %s -S -o - | \
+; RUN:   opt -strip -strip-dead-prototypes -strip-module-flags -S -o %t.after
+; RUN: diff %t.before %t.after
+
+; Check that stripped IR compares equal before and after applying debugify.
+; RUN: opt -O1 < %s | \
+; RUN:   opt -strip -strip-dead-prototypes -strip-module-flags | \
+; RUN:   llvm-dis -o %t.before
+; RUN: opt -O1 -debugify-each < %s | \
+; RUN:   opt -strip -strip-dead-prototypes -strip-module-flags | \
+; RUN:   llvm-dis -o %t.after
+; RUN: diff %t.before %t.after
+
+define void @foo(i32 %arg) {
+  call i32 asm "bswap $0", "=r,r"(i32 %arg)
   ret void
 }
 

Modified: llvm/trunk/tools/opt/opt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/opt/opt.cpp?rev=333861&r1=333860&r2=333861&view=diff
==============================================================================
--- llvm/trunk/tools/opt/opt.cpp (original)
+++ llvm/trunk/tools/opt/opt.cpp Sun Jun  3 17:11:49 2018
@@ -269,8 +269,8 @@ public:
   using super = legacy::PassManager;
 
   void add(Pass *P) override {
-    bool WrapWithDebugify =
-        DebugifyEach && !P->getAsImmutablePass() && !isIRPrintingPass(P);
+    bool WrapWithDebugify = DebugifyEach && !P->getAsImmutablePass() &&
+                            !isIRPrintingPass(P) && !isBitcodeWriterPass(P);
     if (!WrapWithDebugify) {
       super::add(P);
       return;