automation/eclair: extend existing deviations of MISRA C Rule 16.3

Update ECLAIR configuration to deviate more cases where an
unintentional fallthrough cannot happen.

Tag Rule 16.3 as clean for arm.

Signed-off-by: Federico Serafini <federico.serafini@bugseng.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

automation/eclair_analysis/ECLAIR/deviations.ecl

@@ -461,14 +461,30 @@ therefore it is deemed better to leave such files as is."
 -config=MC3R1.R16.2,reports+={deliberate, "any_area(any_loc(file(x86_emulate||x86_svm_emulate)))"}
 -doc_end
 
--doc_begin="Switch clauses ending with continue, goto, return statements are
-safe."
--config=MC3R1.R16.3,terminals+={safe, "node(continue_stmt||goto_stmt||return_stmt)"}
+-doc_begin="Statements that change the control flow (i.e., break, continue, goto, return) and calls to functions that do not return the control back are \"allowed terminal statements\"."
+-stmt_selector+={r16_3_allowed_terminal, "node(break_stmt||continue_stmt||goto_stmt||return_stmt)||call(property(noreturn))"}
+-config=MC3R1.R16.3,terminals+={safe, "r16_3_allowed_terminal"}
 -doc_end
 
--doc_begin="Switch clauses ending with a call to a function that does not give
-the control back (i.e., a function with attribute noreturn) are safe."
--config=MC3R1.R16.3,terminals+={safe, "call(property(noreturn))"}
+-doc_begin="An if-else statement having both branches ending with an allowed terminal statement is itself an allowed terminal statement."
+-stmt_selector+={r16_3_if, "node(if_stmt)&&(child(then,r16_3_allowed_terminal)||child(then,any_stmt(stmt,-1,r16_3_allowed_terminal)))"}
+-stmt_selector+={r16_3_else, "node(if_stmt)&&(child(else,r16_3_allowed_terminal)||child(else,any_stmt(stmt,-1,r16_3_allowed_terminal)))"}
+-stmt_selector+={r16_3_if_else, "r16_3_if&&r16_3_else"}
+-config=MC3R1.R16.3,terminals+={safe, "r16_3_if_else"}
+-doc_end
+
+-doc_begin="An if-else statement having an always true condition and the true branch ending with an allowed terminal statement is itself an allowed terminal statement."
+-stmt_selector+={r16_3_if_true, "r16_3_if&&child(cond,definitely_in(1..))"}
+-config=MC3R1.R16.3,terminals+={safe, "r16_3_if_true"}
+-doc_end
+
+-doc_begin="A switch clause ending with a statement expression which, in turn, ends with an allowed terminal statement is safe."
+-config=MC3R1.R16.3,terminals+={safe, "node(stmt_expr)&&child(stmt,node(compound_stmt)&&any_stmt(stmt,-1,r16_3_allowed_terminal||r16_3_if_else||r16_3_if_true))"}
+-doc_end
+
+-doc_begin="A switch clause ending with a do-while-false the body of which, in turn, ends with an allowed terminal statement is safe.
+An exception to that is the macro ASSERT_UNREACHABLE() which is effective in debug build only: a switch clause ending with ASSERT_UNREACHABLE() is not considered safe."
+-config=MC3R1.R16.3,terminals+={safe, "!macro(name(ASSERT_UNREACHABLE))&&node(do_stmt)&&child(cond,definitely_in(0))&&child(body,any_stmt(stmt,-1,r16_3_allowed_terminal||r16_3_if_else||r16_3_if_true))"}
 -doc_end
 
 -doc_begin="Switch clauses ending with pseudo-keyword \"fallthrough\" are