[PATCH] PR c/68473: sanitize source range-printing within certain macro expansions

David Malcolm dmalcolm@redhat.com
Mon Nov 23 17:59:00 GMT 2015


This patch fixes PR c/68473 by bulletproofing the new
diagnostic_show_locus implementation against ranges that finish before
they start (which can happen when using the C preprocessor), falling
back to simply printing a caret.

Successfully bootstrapped&regrtested on x86_64-pc-linux-gnu; adds 7 new
PASS results to gcc.sum.

OK for trunk?

gcc/ChangeLog:
	PR c/68473
	* diagnostic-show-locus.c (layout::layout): Make loc_range const.
	Sanitize the layout_range against ranges that finish before they
	start.

gcc/testsuite/ChangeLog:
	PR c/68473
	* gcc.dg/plugin/diagnostic-test-expressions-1.c (fminl): New decl.
	(TEST_EQ): New macro.
	(test_macro): New function.
	* gcc.target/i386/pr68473-1.c: New test case.
---
 gcc/diagnostic-show-locus.c                        | 34 ++++++++++++++++++----
 .../gcc.dg/plugin/diagnostic-test-expressions-1.c  | 17 +++++++++++
 gcc/testsuite/gcc.target/i386/pr68473-1.c          | 24 +++++++++++++++
 3 files changed, 69 insertions(+), 6 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr68473-1.c

diff --git a/gcc/diagnostic-show-locus.c b/gcc/diagnostic-show-locus.c
index 9e51b95..968b3cb 100644
--- a/gcc/diagnostic-show-locus.c
+++ b/gcc/diagnostic-show-locus.c
@@ -444,7 +444,7 @@ layout::layout (diagnostic_context * context,
     {
       /* This diagnostic printer can only cope with "sufficiently sane" ranges.
 	 Ignore any ranges that are awkward to handle.  */
-      location_range *loc_range = richloc->get_range (idx);
+      const location_range *loc_range = richloc->get_range (idx);
 
       /* If any part of the range isn't in the same file as the primary
 	 location of this diagnostic, ignore the range.  */
@@ -456,16 +456,38 @@ layout::layout (diagnostic_context * context,
 	if (loc_range->m_caret.file != m_exploc.file)
 	  continue;
 
+      /* Everything is now known to be in the correct source file,
+	 but it may require further sanitization.  */
+      layout_range ri (loc_range);
+
+      /* If we have a range that finishes before it starts (perhaps
+	 from something built via macro expansion), printing the
+	 range is likely to be nonsensical.  Also, attempting to do so
+	 breaks assumptions within the printing code  (PR c/68473).  */
+      if (loc_range->m_start.line > loc_range->m_finish.line)
+	{
+	  /* Is this the primary location?  */
+	  if (m_layout_ranges.length () == 0)
+	    {
+	      /* We want to print the caret for the primary location, but
+		 we must sanitize away m_start and m_finish.  */
+	      ri.m_start = ri.m_caret;
+	      ri.m_finish = ri.m_caret;
+	    }
+	  else
+	    /* This is a non-primary range; ignore it.  */
+	    continue;
+	}
+
       /* Passed all the tests; add the range to m_layout_ranges so that
 	 it will be printed.  */
-      layout_range ri (loc_range);
       m_layout_ranges.safe_push (ri);
 
       /* Update m_first_line/m_last_line if necessary.  */
-      if (loc_range->m_start.line < m_first_line)
-	m_first_line = loc_range->m_start.line;
-      if (loc_range->m_finish.line > m_last_line)
-	m_last_line = loc_range->m_finish.line;
+      if (ri.m_start.m_line < m_first_line)
+	m_first_line = ri.m_start.m_line;
+      if (ri.m_finish.m_line > m_last_line)
+	m_last_line = ri.m_finish.m_line;
     }
 
   /* Adjust m_x_offset.
diff --git a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c
index 0d8c7c5..3e38035 100644
--- a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c
+++ b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c
@@ -541,3 +541,20 @@ void test_quadratic (double a, double b, double c)
    { dg-end-multiline-output "" } */
 
 }
+
+/* Reproducer for PR c/68473.  */
+
+extern long double fminl (long double __x, long double __y);
+#define TEST_EQ(FUNC) FUNC##l(xl,xl)
+void test_macro (long double xl)
+{
+  __emit_expression_range (0, TEST_EQ (fmin) ); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, TEST_EQ (fmin) );
+                                        ^
+   { dg-end-multiline-output "" } */
+/* { dg-begin-multiline-output "" }
+ #define TEST_EQ(FUNC) FUNC##l(xl,xl)
+                       ^~~~
+   { dg-end-multiline-output "" } */
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr68473-1.c b/gcc/testsuite/gcc.target/i386/pr68473-1.c
new file mode 100644
index 0000000..ffffaa7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68473-1.c
@@ -0,0 +1,24 @@
+/* { dg-options "-fdiagnostics-show-caret -mno-fp-ret-in-387" } */
+
+extern long double fminl (long double __x, long double __y);
+
+#define TEST_EQ(FUNC) do { \
+  if ((long)FUNC##l(xl,xl) != (long)xl) \
+    return; \
+  } while (0)
+
+void
+foo (long double xl)
+{
+  TEST_EQ (fmin); /* { dg-error "x87 register return with x87 disabled" } */
+}
+
+/* { dg-begin-multiline-output "" }
+   TEST_EQ (fmin);
+            ^
+   { dg-end-multiline-output "" } */
+
+/* { dg-begin-multiline-output "" }
+   if ((long)FUNC##l(xl,xl) != (long)xl) \
+             ^~~~
+   { dg-end-multiline-output "" } */
-- 
1.8.5.3



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