MIR Serialization: use correct line and column numbers for LLVM IR errors.

This commit translates the line and column numbers for LLVM IR
errors from the numbers in the YAML block scalar to the numbers 
in the MIR file so that the MIRParser users can report LLVM IR 
errors with the correct line and column numbers.

Reviewers: Duncan P. N. Exon Smith

Differential Revision: http://reviews.llvm.org/D10108

llvm-svn: 238576

lib/CodeGen/MIRParser/MIRParser.cpp

@@ -18,6 +18,7 @@
 #include "llvm/AsmParser/Parser.h"
 #include "llvm/CodeGen/MIRYamlMapping.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Support/LineIterator.h"
 #include "llvm/Support/SMLoc.h"
 #include "llvm/Support/SourceMgr.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -49,6 +50,11 @@ public:
   ///
   /// Return true if an error occurred.
   bool parseMachineFunction(yaml::Input &In);
+
+private:
+  /// Return a MIR diagnostic converted from an LLVM assembly diagnostic.
+  SMDiagnostic diagFromLLVMAssemblyDiag(const SMDiagnostic &Error,
+                                        SMRange SourceRange);
 };
 
 } // end anonymous namespace
@@ -81,8 +87,10 @@ std::unique_ptr<Module> MIRParserImpl::parse(SMDiagnostic &Error) {
           dyn_cast_or_null<yaml::BlockScalarNode>(In.getCurrentNode())) {
     M = parseAssembly(MemoryBufferRef(BSN->getValue(), Filename), Error,
                       Context);
-    if (!M)
+    if (!M) {
+      Error = diagFromLLVMAssemblyDiag(Error, BSN->getSourceRange());
       return M;
+    }
     In.nextDocument();
     if (!In.setCurrentDocument())
       return M;
@@ -111,6 +119,37 @@ bool MIRParserImpl::parseMachineFunction(yaml::Input &In) {
   return false;
 }
 
+SMDiagnostic MIRParserImpl::diagFromLLVMAssemblyDiag(const SMDiagnostic &Error,
+                                                     SMRange SourceRange) {
+  assert(SourceRange.isValid());
+
+  // Translate the location of the error from the location in the llvm IR string
+  // to the corresponding location in the MIR file.
+  auto LineAndColumn = SM.getLineAndColumn(SourceRange.Start);
+  unsigned Line = LineAndColumn.first + Error.getLineNo() - 1;
+  unsigned Column = Error.getColumnNo();
+  StringRef LineStr = Error.getLineContents();
+  SMLoc Loc = Error.getLoc();
+
+  // Get the full line and adjust the column number by taking the indentation of
+  // LLVM IR into account.
+  for (line_iterator L(*SM.getMemoryBuffer(SM.getMainFileID()), false), E;
+       L != E; ++L) {
+    if (L.line_number() == Line) {
+      LineStr = *L;
+      Loc = SMLoc::getFromPointer(LineStr.data());
+      auto Indent = LineStr.find(Error.getLineContents());
+      if (Indent != StringRef::npos)
+        Column += Indent;
+      break;
+    }
+  }
+
+  return SMDiagnostic(SM, Loc, Filename, Line, Column, Error.getKind(),
+                      Error.getMessage(), LineStr, Error.getRanges(),
+                      Error.getFixIts());
+}
+
 std::unique_ptr<Module> llvm::parseMIRFile(StringRef Filename,
                                            SMDiagnostic &Error,
                                            LLVMContext &Context) {

test/CodeGen/MIR/llvm-ir-error-reported.mir

@@ -0,0 +1,22 @@
+# RUN: not llc -start-after branch-folder -stop-after branch-folder -o /dev/null %s 2>&1 | FileCheck %s
+# This test ensures an error is reported if the embedded LLVM IR contains an
+# error.
+
+--- |
+  
+  ; CHECK: [[@LINE+3]]:15: error: use of undefined value '%a'
+  define i32 @foo(i32 %x, i32 %y) {
+    %z = alloca i32, align 4
+    store i32 %a, i32* %z, align 4
+    br label %Test
+  Test:
+    %m = load i32, i32* %z, align 4
+    %cond = icmp eq i32 %y, %m
+    br i1 %cond, label %IfEqual, label %IfUnequal
+  IfEqual:
+    ret i32 1
+  IfUnequal:
+    ret i32 0
+  }
+  
+...