[igt-dev] [PATCH i-g-t 1/1] lib: Help static analyzers figure out the execution flow

[Petri Latvala <petri.latvala@intel.com>]

When running any kind of static analysis on IGT, one tends to drown in
warnings about using uninitialized variables in subtests, because
static analysis is unable to figure out that igt_fixture blocks are
always entered if a subtest block is entered. Aid the discovery of
correct execution flow by making static analysis always enter all
igt_fixture blocks and all subtest blocks.

Automatic discovery of static analyzers is done for Clang, Coverity
and Klocwork, using macros found by quick googling. For explicit
control on possible other analyzers, defining STATIC_ANALYSIS_BUILD=1
manually will activate this hack.

Signed-off-by: Petri Latvala <petri.latvala@intel.com>
---
lib/igt_core.h | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/lib/igt_core.h b/lib/igt_core.h
index b80e1702..0f643f6b 100644
--- a/lib/igt_core.h
+++ b/lib/igt_core.h
@@ -46,6 +46,14 @@
 #endif
 
 
+#ifndef STATIC_ANALYSIS_BUILD
+#if defined(__clang_analyzer__) || defined(__COVERITY__) || defined(__KLOCWORK__)
+#define STATIC_ANALYSIS_BUILD 1
+#else
+#define STATIC_ANALYSIS_BUILD 0
+#endif
+#endif
+
 extern const char* __igt_test_description __attribute__((weak));
 extern bool __igt_plain_output;
 extern char *igt_frame_dump_path;
@@ -109,9 +117,10 @@ void __igt_fixture_end(void) __attribute__((noreturn));
  * blocks should be annotated with igt_fixture.
  */
 #define igt_fixture for (volatile int igt_tokencat(__tmpint,__LINE__) = 0; \
+                         STATIC_ANALYSIS_BUILD || ( \
 			 igt_tokencat(__tmpint,__LINE__) < 1 && \
 			 __igt_fixture() && \
-			 (sigsetjmp(igt_subtest_jmpbuf, 1) == 0); \
+			 (sigsetjmp(igt_subtest_jmpbuf, 1) == 0)); \
 			 igt_tokencat(__tmpint,__LINE__) ++, \
 			 __igt_fixture_complete())
 
@@ -169,15 +178,17 @@ bool __igt_run_subtest(const char *subtest_name);
  *
  * This is a simpler version of igt_subtest_f()
  */
-#define igt_subtest(name) for (; __igt_run_subtest((name)) && \
-				   (sigsetjmp(igt_subtest_jmpbuf, 1) == 0); \
-				   igt_success())
+#define igt_subtest(name) for (; STATIC_ANALYSIS_BUILD ||		\
+				       (__igt_run_subtest((name)) &&	\
+					(sigsetjmp(igt_subtest_jmpbuf, 1) == 0)); \
+                                  igt_success())
 #define __igt_subtest_f(tmp, format...) \
 	for (char tmp [256]; \
-	     snprintf( tmp , sizeof( tmp ), \
+	     STATIC_ANALYSIS_BUILD || \
+	     ((snprintf( tmp , sizeof( tmp ), \
 		      format), \
-	     __igt_run_subtest( tmp ) && \
-	     (sigsetjmp(igt_subtest_jmpbuf, 1) == 0); \
+	       __igt_run_subtest( tmp )) && \
+	      (sigsetjmp(igt_subtest_jmpbuf, 1) == 0)); \
 	     igt_success())
 
 /**
-- 
2.18.0

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