[CodeGen] Print executed statement instances at runtime.

Add the options -polly-codegen-trace-stmts and
-polly-codegen-trace-scalars. When enabled, adds a call to the
beginning of every generated statement that prints the executed
statement instance. With -polly-codegen-trace-scalars, it also prints
the value of all scalars that are used in the statement, and PHIs
defined in the beginning of the statement.

Differential Revision: https://reviews.llvm.org/D45743

llvm-svn: 330864

2 files changed, 42 insertions, 1 deletions

diff --git a/polly/include/polly/CodeGen/BlockGenerators.h b/polly/include/polly/CodeGen/BlockGenerators.h
index 35f23c46932..23ebf058120 100644
--- a/polly/include/polly/CodeGen/BlockGenerators.h
+++ b/polly/include/polly/CodeGen/BlockGenerators.h
@@ -329,6 +329,25 @@ protected:
                            ValueMapT &BBMap,
                            __isl_keep isl_id_to_ast_expr *NewAccesses);
 
+  /// When statement tracing is enable, build the print instructions for
+  /// printing the current statement instance and its input scalars.
+  ///
+  /// The printed output looks like:
+  ///
+  ///     Stmt1(0)
+  ///
+  /// If printing of scalars is enabled, it also appends the value of each
+  /// scalar to the line:
+  ///
+  ///     Stmt1(0) %i=1 %sum=5
+  ///
+  /// @param Stmt  The statement we generate code for.
+  /// @param LTS   A mapping from loops virtual canonical induction
+  ///              variable to their new values.
+  /// @param BBMap A mapping from old values to their new values in this block.
+  void generateBeginStmtTrace(ScopStmt &Stmt, LoopToScevMapT &LTS,
+                              ValueMapT &BBMap);
+
   /// Generate instructions that compute whether one instance of @p Set is
   /// executed.
   ///
diff --git a/polly/include/polly/CodeGen/RuntimeDebugBuilder.h b/polly/include/polly/CodeGen/RuntimeDebugBuilder.h
index 334030fd3c3..a0820f9b628 100644
--- a/polly/include/polly/CodeGen/RuntimeDebugBuilder.h
+++ b/polly/include/polly/CodeGen/RuntimeDebugBuilder.h
@@ -30,6 +30,28 @@ namespace polly {
 /// run time.
 struct RuntimeDebugBuilder {
 
+  /// Generate a constant string into the builder's llvm::Module which can be
+  /// passed to createGPUPrinter() or createGPUPrinter().
+  ///
+  /// @param Builder The builder used to emit the printer calls.
+  /// @param Str     The string to be printed.
+
+  /// @return        A global containing @p Str.
+  static llvm::Value *getPrintableString(PollyIRBuilder &Builder,
+                                         llvm::StringRef Str) {
+    // TODO: Get rid of magic number 4. It it NVPTX's constant address space and
+    // works on X86 (CPU) only because its backend ignores the address space.
+    return Builder.CreateGlobalStringPtr(Str, "", 4);
+  }
+
+  /// Return whether an llvm::Value of the type @p Ty is printable for
+  /// debugging.
+  ///
+  /// That is, whether such a value can be passed to createGPUPrinter() or
+  /// createGPUPrinter() to be dumped as runtime.  If false is returned, those
+  /// functions will fail.
+  static bool isPrintable(llvm::Type *Ty);
+
   /// Print a set of LLVM-IR Values or StringRefs via printf
   ///
   ///  This function emits a call to printf that will print the given arguments.
@@ -78,7 +100,7 @@ private:
   static void createPrinter(PollyIRBuilder &Builder, bool UseGPU,
                             std::vector<llvm::Value *> &Values,
                             llvm::StringRef String, Args... args) {
-    Values.push_back(Builder.CreateGlobalStringPtr(String, "", 4));
+    Values.push_back(getPrintableString(Builder, String));
     createPrinter(Builder, UseGPU, Values, args...);
   }