[xen staging] automation/eclair: update configuration of Rule 20.7

[patchbot@xxxxxxx]

commit 3c5c9743ca5918e265beb4ec52695e67b07df3d4
Author:     Federico Serafini <federico.serafini@xxxxxxxxxxx>
AuthorDate: Wed Sep 11 17:34:37 2024 -0700
Commit:     Stefano Stabellini <stefano.stabellini@xxxxxxx>
CommitDate: Wed Sep 11 17:34:37 2024 -0700

    automation/eclair: update configuration of Rule 20.7
    
    MISRA C:2012 Rule 20.7 states that "Expressions resulting from the
    expansion of macro parameters shall be enclosed in parentheses".
    The rational of the rule is that if a macro argument expands to an
    expression, there may be problems related to operator precedence, e.g.,
    
    define M(A, B) A * B
    
    M(1+1, 2+2) will expand to: 1+1 * 2+2
    
    Update ECLAIR configuration to tag as 'safe' the expansions of macro
    arguments surrounded tokens '{', '}' and ';', since in their presence
    problems related to operator precedence can not occur.
    
    Signed-off-by: Federico Serafini <federico.serafini@xxxxxxxxxxx>
    Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 automation/eclair_analysis/ECLAIR/deviations.ecl | 4 ++++
 docs/misra/deviations.rst                        | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/automation/eclair_analysis/ECLAIR/deviations.ecl 
b/automation/eclair_analysis/ECLAIR/deviations.ecl
index 9c3ebc9cc7..6679caf3da 100644
--- a/automation/eclair_analysis/ECLAIR/deviations.ecl
+++ b/automation/eclair_analysis/ECLAIR/deviations.ecl
@@ -598,6 +598,10 @@ use of this macro, it is deemed ok to deviate them."
 -config=MC3R1.R20.7,reports+={deliberate, 
"any_area(any_loc(any_exp(macro(^(COMPILE_CHECK|RUNTIME_CHECK)$))))"}
 -doc_end
 
+-doc_begin="Problems related to operator precedence can not occur if the 
expansion of the macro argument is surrounded by tokens '{', '}' and ';'."
+-config=MC3R1.R20.7,expansion_context+={safe, "left_right(^[\\{;]$,^[;\\}]$)"}
+-doc_end
+
 -doc_begin="Uses of variadic macros that have one of their arguments defined as
 a macro and used within the body for both ordinary parameter expansion and as 
an
 operand to the # or ## operators have a behavior that is well-understood and
diff --git a/docs/misra/deviations.rst b/docs/misra/deviations.rst
index 247e69e7f1..15a993d050 100644
--- a/docs/misra/deviations.rst
+++ b/docs/misra/deviations.rst
@@ -552,6 +552,11 @@ Deviations related to MISRA C:2012 Rules:
        usage scope, omitting parentheses is deemed unlikely to cause issues.
      - Tagged as `deliberate` for ECLAIR.
 
+   * - R20.7
+     - Problems related to operator precedence can not occur if the expansion
+       of the macro argument is surrounded by tokens '{', '}' and ';'.
+     - Tagged as `safe` for ECLAIR.
+
    * - R20.12
      - Variadic macros that use token pasting often employ the gcc extension
        `ext_paste_comma`, as detailed in `C-language-toolchain.rst`, which is
--
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