commit 1cc0d628552a43568ec7c143698025ab18f2e072
author Dan Gohman <gohman@apple.com> Wed May 05 23:41:32 2010 +0000
committer Dan Gohman <gohman@apple.com> Wed May 05 23:41:32 2010 +0000
tree 1d7064bf0f504ca4d7a77e424f0b445ac8e54f40
parent b7d0688195a7bac5b53361d7b44d56b813d30246

Emit debug info for MachineInstrs with unknown debug locations, instead
of just letting them inherit the debug locations of adjacent instructions.

Debug info should aim to be either accurate or absent.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103135 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/AsmPrinter/DwarfDebug.cpp

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index e9e9ba5..4da5498 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2150,8 +2150,20 @@
 void DwarfDebug::beginScope(const MachineInstr *MI) {
   // Check location.
   DebugLoc DL = MI->getDebugLoc();
-  if (DL.isUnknown())
+  if (DL.isUnknown()) {
+    // This instruction has no debug location. If the preceding instruction
+    // did, emit debug location information to indicate that the debug
+    // location is now unknown.
+    MCSymbol *Label = NULL;
+    if (DL == PrevInstLoc)
+      Label = PrevLabel;
+    else {
+      Label = recordSourceLine(DL.getLine(), DL.getCol(), 0);
+      PrevInstLoc = DL;
+      PrevLabel = Label;
+    }
     return;
+  }
 
   MDNode *Scope = DL.getScope(Asm->MF->getFunction()->getContext());
   
@@ -2564,23 +2576,28 @@
   StringRef Dir;
   StringRef Fn;
 
-  DIDescriptor Scope(S);
-  if (Scope.isCompileUnit()) {
-    DICompileUnit CU(S);
-    Dir = CU.getDirectory();
-    Fn = CU.getFilename();
-  } else if (Scope.isSubprogram()) {
-    DISubprogram SP(S);
-    Dir = SP.getDirectory();
-    Fn = SP.getFilename();
-  } else if (Scope.isLexicalBlock()) {
-    DILexicalBlock DB(S);
-    Dir = DB.getDirectory();
-    Fn = DB.getFilename();
-  } else
-    assert(0 && "Unexpected scope info");
+  unsigned Src = 1;
+  if (S) {
+    DIDescriptor Scope(S);
 
-  unsigned Src = GetOrCreateSourceID(Dir, Fn);
+    if (Scope.isCompileUnit()) {
+      DICompileUnit CU(S);
+      Dir = CU.getDirectory();
+      Fn = CU.getFilename();
+    } else if (Scope.isSubprogram()) {
+      DISubprogram SP(S);
+      Dir = SP.getDirectory();
+      Fn = SP.getFilename();
+    } else if (Scope.isLexicalBlock()) {
+      DILexicalBlock DB(S);
+      Dir = DB.getDirectory();
+      Fn = DB.getFilename();
+    } else
+      assert(0 && "Unexpected scope info");
+
+    Src = GetOrCreateSourceID(Dir, Fn);
+  }
+
   MCSymbol *Label = MMI->getContext().CreateTempSymbol();
   Lines.push_back(SrcLineInfo(Line, Col, Src, Label));
 
@@ -2967,8 +2984,6 @@
       MCSymbol *Label = LineInfo.getLabel();
       if (!Label->isDefined()) continue; // Not emitted, in dead code.
 
-      if (LineInfo.getLine() == 0) continue;
-
       if (Asm->isVerbose()) {
         std::pair<unsigned, unsigned> SrcID =
           getSourceDirectoryAndFileIds(LineInfo.getSourceID());