[asan] implement an experimental detector of ODR violations. Not tested yet outside of a tiny test, may need tuning.

llvm-svn: 207210

compiler-rt/lib/asan/asan_flags.h

@@ -64,6 +64,7 @@ struct Flags {
   bool start_deactivated;
   int detect_invalid_pointer_pairs;
   bool detect_container_overflow;
+  bool detect_odr_violation;
 };
 
 extern Flags asan_flags_dont_use_directly;

compiler-rt/lib/asan/asan_globals.cc

@@ -92,6 +92,18 @@ static void RegisterGlobal(const Global *g) {
   CHECK(AddrIsInMem(g->beg));
   CHECK(AddrIsAlignedByGranularity(g->beg));
   CHECK(AddrIsAlignedByGranularity(g->size_with_redzone));
+  if (flags()->detect_odr_violation) {
+    // Try detecting ODR (One Definition Rule) violation, i.e. the situation
+    // where two globals with the same name are defined in different modules.
+    if (__asan_region_is_poisoned(g->beg, g->size_with_redzone)) {
+      // This check may not be enough: if the first global is much larger
+      // the entire redzone of the second global may be within the first global.
+      for (ListOfGlobals *l = list_of_all_globals; l; l = l->next) {
+        if (g->beg == l->g->beg)
+          ReportODRViolation(g, l->g);
+      }
+    }
+  }
   if (flags()->poison_heap)
     PoisonRedZones(*g);
   ListOfGlobals *l = new(allocator_for_globals) ListOfGlobals;

compiler-rt/lib/asan/asan_report.cc

@@ -729,6 +729,19 @@ void ReportBadParamsToAnnotateContiguousContainer(uptr beg, uptr end,
   ReportErrorSummary("bad-__sanitizer_annotate_contiguous_container", stack);
 }
 
+void ReportODRViolation(const __asan_global *g1, const __asan_global *g2) {
+  ScopedInErrorReport in_report;
+  Decorator d;
+  Printf("%s", d.Warning());
+  Report("ERROR: AddressSanitizer: odr-violation (%p):\n", g1->beg);
+  Printf("%s", d.EndWarning());
+  Printf("  [1] size=%zd %s %s\n", g1->size, g1->name, g1->module_name);
+  Printf("  [2] size=%zd %s %s\n", g2->size, g2->name, g2->module_name);
+  Report("HINT: if you don't care about these warnings you may set "
+         "ASAN_OPTIONS=detect_odr_violation=0\n");
+  ReportErrorSummary("odr-violation", g1->module_name, 0, g1->name);
+}
+
 // ----------------------- CheckForInvalidPointerPair ----------- {{{1
 static NOINLINE void
 ReportInvalidPointerPair(uptr pc, uptr bp, uptr sp, uptr a1, uptr a2) {

compiler-rt/lib/asan/asan_report.h

@@ -54,6 +54,9 @@ void NORETURN
 ReportBadParamsToAnnotateContiguousContainer(uptr beg, uptr end, uptr old_mid,
                                              uptr new_mid, StackTrace *stack);
 
+void NORETURN
+ReportODRViolation(const __asan_global *g1, const __asan_global *g2);
+
 // Mac-specific errors and warnings.
 void WarnMacFreeUnallocated(
     uptr addr, uptr zone_ptr, const char *zone_name, StackTrace *stack);

compiler-rt/lib/asan/asan_rtl.cc

@@ -225,6 +225,10 @@ static void ParseFlagsFromString(Flags *f, const char *str) {
       "detect_container_overflow",
       "If true, honor the container overflow  annotations. "
       "See https://code.google.com/p/address-sanitizer/wiki/ContainerOverflow");
+
+  ParseFlag(str, &f->detect_odr_violation,
+      "detect_odr_violation",
+      "If true, detect violation of One-Definition-Rule (ODR) ");
 }
 
 void InitializeFlags(Flags *f, const char *env) {

compiler-rt/test/asan/TestCases/Linux/odr-violation.cc

@@ -0,0 +1,23 @@
+// RUN: %clangxx_asan -DBUILD_SO=1 -fPIC -shared %s -o %t.so
+// RUN: %clangxx_asan %s %t.so -Wl,-R. -o %t
+// RUN: ASAN_OPTIONS=detect_odr_violation=1 not %t 2>&1 | FileCheck %s
+// RUN: ASAN_OPTIONS=detect_odr_violation=0     %t 2>&1 | FileCheck %s --check-prefix=DISABLED
+// RUN:                                         %t 2>&1 | FileCheck %s --check-prefix=DISABLED
+
+#ifndef SZ
+# define SZ 4
+#endif
+
+#if BUILD_SO
+char G[SZ];
+#else
+#include <stdio.h>
+char G[100];
+int main(int argc, char **argv) {
+  printf("PASS: %p\n", &G);
+}
+#endif
+
+// CHECK: ERROR: AddressSanitizer: odr-violation
+// CHECK: size=100 G
+// DISABLED: PASS