IR printing improvement for function passes - introducing -print-module-scope

Summary:
When debugging function passes it happens to be rather useful to dump
the whole module before the transformation and then use this dump
to analyze this single transformation by running it separately
on that particular module state.

Introducing
    -print-module-scope
debugging option that forces all the function-level IR dumps
to become whole-module dumps.

This option builds on top of normal dumping controls like
   -print-before/after
   -filter-print-funcs

The plan is to eventually extend this option to cover other local passes
(at least loop passes) but that should go as a separate change.

Reviewers: sanjoy, weimingz, silvas, fedor.sergeev

Reviewed By: weimingz

Subscribers: apilipenko, skatkov, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D40245

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319561 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 73 insertions, 1 deletions

diff --git a/include/llvm/Pass.h b/include/llvm/Pass.h
index ff641170350..a29b3771abb 100644
--- a/include/llvm/Pass.h
+++ b/include/llvm/Pass.h
@@ -361,6 +361,12 @@ extern bool TimePassesIsEnabled;
 //  @brief Tells if the function IR should be printed by PrinterPass.
 extern bool isFunctionInPrintList(StringRef FunctionName);
 
+/// forcePrintModuleIR - returns true if IR printing passes should
+//  be printing module IR (even for local-pass printers e.g. function-pass)
+//  to provide more context, as enabled by debugging option -print-module-scope
+//  @brief Tells if IR printer should be printing module IR
+extern bool forcePrintModuleIR();
+
 } // end namespace llvm
 
 // Include support files that contain important APIs commonly used by Passes,
diff --git a/lib/IR/IRPrintingPasses.cpp b/lib/IR/IRPrintingPasses.cpp
index 4c8afda18b7..3308ef4c249 100644
--- a/lib/IR/IRPrintingPasses.cpp
+++ b/lib/IR/IRPrintingPasses.cpp
@@ -45,7 +45,10 @@ PrintFunctionPass::PrintFunctionPass(raw_ostream &OS, const std::string &Banner)
 PreservedAnalyses PrintFunctionPass::run(Function &F,
                                          FunctionAnalysisManager &) {
   if (isFunctionInPrintList(F.getName()))
-    OS << Banner << static_cast<Value &>(F);
+    if (forcePrintModuleIR())
+      OS << Banner << " (function: " << F.getName() << ")\n" << *F.getParent();
+    else
+      OS << Banner << static_cast<Value &>(F);
   return PreservedAnalyses::all();
 }
 
diff --git a/lib/IR/LegacyPassManager.cpp b/lib/IR/LegacyPassManager.cpp
index c13893d1a9e..8bd9ed6ef0f 100644
--- a/lib/IR/LegacyPassManager.cpp
+++ b/lib/IR/LegacyPassManager.cpp
@@ -82,6 +82,12 @@ static cl::opt<bool> PrintAfterAll("print-after-all",
                                    llvm::cl::desc("Print IR after each pass"),
                                    cl::init(false), cl::Hidden);
 
+static cl::opt<bool>
+    PrintModuleScope("print-module-scope",
+                     cl::desc("When printing IR for print-[before|after]{-all} "
+                              "always print a module IR"),
+                     cl::init(false));
+
 static cl::list<std::string>
     PrintFuncsList("filter-print-funcs", cl::value_desc("function names"),
                    cl::desc("Only print IR for functions whose name "
@@ -115,6 +121,8 @@ static bool ShouldPrintAfterPass(const PassInfo *PI) {
   return PrintAfterAll || ShouldPrintBeforeOrAfterPass(PI, PrintAfter);
 }
 
+bool llvm::forcePrintModuleIR() { return PrintModuleScope; }
+
 bool llvm::isFunctionInPrintList(StringRef FunctionName) {
   static std::unordered_set<std::string> PrintFuncNames(PrintFuncsList.begin(),
                                                         PrintFuncsList.end());
diff --git a/test/Other/print-module-scope.ll b/test/Other/print-module-scope.ll
new file mode 100644
index 00000000000..0e9c4d59cc3
--- /dev/null
+++ b/test/Other/print-module-scope.ll
@@ -0,0 +1,55 @@
+; This test is checking basic properties of -print-module-scope options:
+;   - dumps all the module IR at once
+;   - all the function attributes are shown, including those of declarations
+;   - works on top of -print-after and -filter-print-funcs
+;
+; RUN: opt < %s 2>&1 -disable-output \
+; RUN: 	   -simplifycfg -print-after=simplifycfg -print-module-scope \
+; RUN:	   | FileCheck %s -check-prefix=CFG
+; RUN: opt < %s 2>&1 -disable-output \
+; RUN: 	   -simplifycfg -print-after=simplifycfg -filter-print-funcs=foo -print-module-scope \
+; RUN:	   | FileCheck %s -check-prefix=FOO
+
+; CFG:      IR Dump After
+; CFG-SAME:   function: foo
+; CFG-NEXT: ModuleID =
+; CFG: define void @foo
+; CFG: define void @bar
+; CFG: declare void @baz
+; CFG: IR Dump After
+; CFG-SAME:   function: bar
+; CFG-NEXT: ModuleID =
+; CFG: define void @foo
+; CFG: define void @bar
+; CFG: declare void @baz
+
+; FOO:      IR Dump After
+; FOO-NOT:    function: bar
+; FOO-SAME:   function: foo
+; FOO-NEXT: ModuleID =
+; FOO:   Function Attrs: nounwind ssp
+; FOO: define void @foo
+; FOO:   Function Attrs: nounwind
+; FOO: define void @bar
+; FOO:   Function Attrs: nounwind readnone ssp
+; FOO: declare void @baz
+
+define void @foo() nounwind ssp {
+  call void @baz()
+  ret void
+}
+
+define void @bar() #0 {
+  ret void
+}
+
+declare void @baz() #1
+
+attributes #0 = { nounwind "no-frame-pointer-elim"="true" }
+
+attributes #1 = { nounwind readnone ssp "use-soft-float"="false" }
+; FOO: attributes #{{[0-9]}} = { nounwind "no-frame-pointer-elim"="true" }
+
+; FOO: attributes #{{[0-9]}} = { nounwind readnone ssp "use-soft-float"="false" }
+
+; FOO-NOT: IR Dump