diff options
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/doc/invoke.texi | 22 |
2 files changed, 17 insertions, 10 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 1992d34..e2106f5 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2016-11-05 Martin Sebor <msebor@redhat.com> + + * doc/invoke.texi (Warning Options): Correct typos in -Walloca + documentation. + 2016-11-05 David Edelsohn <dje.gcc@gmail.com> PR bootstrap/78188 diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index fb6144a..089661b 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -4997,8 +4997,10 @@ This option warns on all uses of @code{alloca} in the source. @item -Walloca-larger-than=@var{n} This option warns on calls to @code{alloca} that are not bounded by a -controlling predicate limiting its size to @var{n} bytes, or calls to -@code{alloca} where the bound is unknown. +controlling predicate limiting its argument of integer type to at most +@var{n} bytes, or calls to @code{alloca} where the bound is unknown. +Arguments of non-integer types are considered unbounded even if they +appear to be constrained to the expected range. For example, a bounded case of @code{alloca} could be: @@ -5014,13 +5016,13 @@ void func (size_t n) @} @end smallexample -In the above example, passing @code{-Walloca=1000} would not issue a -warning because the call to @code{alloca} is known to be at most 1000 -bytes. However, if @code{-Walloca=500} was passed, the compiler would -have emitted a warning. +In the above example, passing @code{-Walloca-larger-than=1000} would not +issue a warning because the call to @code{alloca} is known to be at most +1000 bytes. However, if @code{-Walloca-larger-than=500} were passed, +the compiler would emit a warning. Unbounded uses, on the other hand, are uses of @code{alloca} with no -controlling predicate verifying its size. For example: +controlling predicate constraining its integer argument. For example: @smallexample void func () @@ -5030,8 +5032,8 @@ void func () @} @end smallexample -If @code{-Walloca=500} was passed, the above would trigger a warning, -but this time because of the lack of bounds checking. +If @code{-Walloca-larger-than=500} were passed, the above would trigger +a warning, but this time because of the lack of bounds checking. Note, that even seemingly correct code involving signed integers could cause a warning: @@ -5048,7 +5050,7 @@ void func (signed int n) @end smallexample In the above example, @var{n} could be negative, causing a larger than -expected argument to be implicitly casted into the @code{alloca} call. +expected argument to be implicitly cast into the @code{alloca} call. This option also warns when @code{alloca} is used in a loop. |