On Dec 4, 2010, at 2:53 AM, sashan wrote:
> Hi
>
> This is related to this thread here:
> http://lists.cs.uiuc.edu/pipermail/cfe-dev/2010-November/012302.html
>
> This patch fixes the incorrect error reporting where the wrong previous line
> was
> identified as containing the duplicate 'default'. The patch also contains a
> test
> case for this. All the other test cases pass. Applying with:
>
> patch -p1 < patchfile
>
> from the clang root source dir should work.
diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index 7ab30d1..5f07fd4 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -550,8 +550,18 @@ Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt
*Switch,
if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) {
if (TheDefaultStmt) {
- Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
- Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
+ PresumedLoc DSPLoc = SourceMgr.getPresumedLoc(DS->getDefaultLoc());
+ PresumedLoc TheDSPLoc =
SourceMgr.getPresumedLoc(TheDefaultStmt->getDefaultLoc());
+
+ // Check which of the default statements is the duplicate by comparing
+ // their line numbers.
+ if (TheDSPLoc.getLine() < DSPLoc.getLine()) {
+ Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
+ Diag(TheDefaultStmt->getDefaultLoc(),
diag::note_duplicate_case_prev);
+ } else {
+ Diag(TheDefaultStmt->getDefaultLoc(),
diag::err_multiple_default_labels_defined);
+ Diag(DS->getDefaultLoc(), diag::note_duplicate_case_prev);
+ }
Comparing just based on the line number won't work, since the two cases could
be in different files, or could appear on the same line.
SourceManager::isBeforeInTranslationUnit() is the appropriate way to compare
two source locations.
That said, I don't think this is the right solution to the problem. I think
that, instead, we should be processing (and probably also storing) the list of
case/default statements in source order rather than reverse source order, as we
currently are. That would address both the problem you're seeing and the other
problems I had previously alluded to, where we get diagnostics about case
values in the opposite order we expect.
- Doug
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