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[PATCH 3/4] glr2.cc: avoid type-punning issues
From: |
Akim Demaille |
Subject: |
[PATCH 3/4] glr2.cc: avoid type-punning issues |
Date: |
Sun, 13 Sep 2020 14:42:38 +0200 |
On the CI, tests fail with GCC 4.6 to GCC 6 as follows:
tests/synclines.at:440: COLUMNS=1000; export COLUMNS; NO_TERM_HYPERLINKS=1;
export NO_TERM_HYPERLINKS; bison --color=no -fno-caret -o \"\\\"\".cc
\"\\\"\".y
tests/synclines.at:440: $CXX $CXXFLAGS $CPPFLAGS $LDFLAGS -o \"\\\"\"
\"\\\"\".cc $LIBS
stderr:
"\"".cc: In member function 'glr_state& glr_stack_item::getState()':
"\"".cc:1404:47: error: dereferencing type-punned pointer will break
strict-aliasing rules [-Werror=strict-aliasing]
return *reinterpret_cast<glr_state*>(&raw_);
^
"\"".cc: In member function 'const glr_state& glr_stack_item::getState()
const':
"\"".cc:1408:53: error: dereferencing type-punned pointer will break
strict-aliasing rules [-Werror=strict-aliasing]
return *reinterpret_cast<const glr_state*>(&raw_);
^
"\"".cc: In member function 'semantic_option& glr_stack_item::getOption()':
"\"".cc:1413:53: error: dereferencing type-punned pointer will break
strict-aliasing rules [-Werror=strict-aliasing]
return *reinterpret_cast<semantic_option*>(&raw_);
^
"\"".cc: In member function 'const semantic_option&
glr_stack_item::getOption() const':
"\"".cc:1417:59: error: dereferencing type-punned pointer will break
strict-aliasing rules [-Werror=strict-aliasing]
return *reinterpret_cast<const semantic_option*>(&raw_);
^
See also be6fa942acae21a4a025bac5e339451be6ad136d.
* data/skeletons/glr2.cc (glr_stack_item): Use a temporary void*
variable to avoid type-punning issues with reinterpret_cast.
---
data/skeletons/glr2.cc | 35 ++++++++++++++++++++++-------------
1 file changed, 22 insertions(+), 13 deletions(-)
diff --git a/data/skeletons/glr2.cc b/data/skeletons/glr2.cc
index 5f6a5c95..f15ab96d 100644
--- a/data/skeletons/glr2.cc
+++ b/data/skeletons/glr2.cc
@@ -1241,24 +1241,33 @@ public:
getOption().~semantic_option();
}
- glr_state& getState() {
- YYDASSERT(is_state());
- return *reinterpret_cast<glr_state*>(&raw_);
+ glr_state& getState ()
+ {
+ YYDASSERT (is_state ());
+ void *yyp = raw_;
+ return *static_cast<glr_state*> (yyp);
}
- const glr_state& getState() const {
- YYDASSERT(is_state());
- return *reinterpret_cast<const glr_state*>(&raw_);
+ const glr_state& getState () const
+ {
+ YYDASSERT (is_state());
+ const void *yyp = raw_;
+ return *static_cast<const glr_state*> (yyp);
}
- semantic_option& getOption() {
- YYDASSERT(!is_state());
- return *reinterpret_cast<semantic_option*>(&raw_);
+ semantic_option& getOption ()
+ {
+ YYDASSERT (!is_state ());
+ void *yyp = raw_;
+ return *static_cast<semantic_option*> (yyp);
}
- const semantic_option& getOption() const {
- YYDASSERT(!is_state());
- return *reinterpret_cast<const semantic_option*>(&raw_);
+ const semantic_option& getOption () const
+ {
+ YYDASSERT (!is_state ());
+ const void *yyp = raw_;
+ return *static_cast<const semantic_option*> (yyp);
}
- bool is_state() const {
+ bool is_state () const
+ {
return is_state_;
}
private:
--
2.28.0