[Qemu-devel] [PATCH] compiler: never omit assertions if using a static analysis tool

[Qemu-devel] [PATCH] compiler: never omit assertions if using a static analysis tool

[Paolo Bonzini]

Assertions help both Coverity and the clang static analyzer avoid
false positives, but on the other hand both are confused when
the condition is compiled as (void)(x != FOO).  Always expand
assertion macros when using Coverity or clang, through a new
QEMU_STATIC_ANALYSIS preprocessor symbol.

This fixes a couple false positives in TCG.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 include/qemu/compiler.h | 3 +++
 tcg/tcg.h               | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h
index b64f899..338d3a6 100644
--- a/include/qemu/compiler.h
+++ b/include/qemu/compiler.h
@@ -3,6 +3,9 @@
 #ifndef COMPILER_H
 #define COMPILER_H
 
+#if defined __clang_analyzer__ || defined __COVERITY__
+#define QEMU_STATIC_ANALYSIS 1
+#endif
 
 /*----------------------------------------------------------------------------
 | The macro QEMU_GNUC_PREREQ tests for minimum version of the GNU C compiler.
diff --git a/tcg/tcg.h b/tcg/tcg.h
index 66ae0c7..6046dcd 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -191,7 +191,7 @@ typedef uint64_t tcg_insn_unit;
 #endif
 
 
-#ifdef CONFIG_DEBUG_TCG
+#if defined CONFIG_DEBUG_TCG || defined QEMU_STATIC_ANALYSIS
 # define tcg_debug_assert(X) do { assert(X); } while (0)
 #elif QEMU_GNUC_PREREQ(4, 5)
 # define tcg_debug_assert(X) \
-- 
2.7.4

Re: [Qemu-devel] [PATCH] compiler: never omit assertions if using a static analysis tool

[Richard Henderson]

On 07/15/2016 09:58 PM, Paolo Bonzini wrote:
> Assertions help both Coverity and the clang static analyzer avoid
> false positives, but on the other hand both are confused when
> the condition is compiled as (void)(x != FOO).  Always expand
> assertion macros when using Coverity or clang, through a new
> QEMU_STATIC_ANALYSIS preprocessor symbol.
>
> This fixes a couple false positives in TCG.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  include/qemu/compiler.h | 3 +++
>  tcg/tcg.h               | 2 +-
>  2 files changed, 4 insertions(+), 1 deletion(-)

Reviewed-by: Richard Henderson <rth@twiddle.net>


r~