diff options
author | Xavier Leroy <xavierleroy@users.noreply.github.com> | 2018-03-30 19:07:54 +0200 |
---|---|---|
committer | GitHub <noreply@github.com> | 2018-03-30 19:07:54 +0200 |
commit | 1ee8c15657cddca0d0727865327ba154b9df45d5 (patch) | |
tree | b823c553f511253e7af83b639820c284098a5f97 /test/regression/Results | |
parent | 6b1463c4de3ae182fac6b5f2d15248d87c2f9613 (diff) | |
download | compcert-kvx-1ee8c15657cddca0d0727865327ba154b9df45d5.tar.gz compcert-kvx-1ee8c15657cddca0d0727865327ba154b9df45d5.zip |
Turn delicate case of designated re-initialization into error (#70)
Consider:
struct P { int x, y; }
struct S { struct P p; }
struct P p0 = { 1,2 };
struct S s1 = { .p = p0; .p.x = 3 };
ISO C99 and recent versions of Clang initialize s1.p.y to 2, i.e.
the initialization of s1.p.y to p0.y implied by ".p = p0" is kept,
even though the initialization of s1.p.x to p0.x is overwritten
by ".p.x = 3".
GCC, old versions of Clang, and previous versions of CompCert
initialize s1.p.y to the default value 0. I.e. the initialization
".p = p0" is forgotten, leaving default values for the fields of .p
before ".p.x = 3" takes effect.
Implementing the proper ISO C99 semantics in CompCert is difficult,
owing to a mismatch between the intended semantics and the C.init
representation of initializers.
This commit turns the delicate case of reinitialization above
(re-initializing a member of a composite that has already been
initialized as a whole) into a compile-time error.
We will then see if the delicate case occurs in practice and needs
further attention.
Diffstat (limited to 'test/regression/Results')
-rw-r--r-- | test/regression/Results/initializers3 | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/test/regression/Results/initializers3 b/test/regression/Results/initializers3 index 8742f8ea..fb20e5a9 100644 --- a/test/regression/Results/initializers3 +++ b/test/regression/Results/initializers3 @@ -7,5 +7,4 @@ x21 = { 'H', 'e', 'l', 'l', 'o', '!', 0, 0, 0, 0, } f(0,42) = 42, f(1,42) = 43, f(2,42) = 44, f(3,42) = 44, f(4,42) = 44 s1 = { tag = 0, a = {66,77}, u = {0,0} } s2 = { tag = 0, a = {0,1}, u = {66,77} } -s3 = { tag = 1, a = {1,0}, u = {'H', 'e', 'l', 'l', 'o', '!', 0, 'X', } } s4 = { tag = 0, a = {66,77}, u = {88,99} } |