From 857664a5d479fe71a830f3e6a6a707d1a3e2bb89 Mon Sep 17 00:00:00 2001
From: Jonas Maebe <jonas@freepascal.org>
Date: Fri, 23 Dec 2005 21:08:48 +0000
Subject: [PATCH] * fixed tw4554: * proper uninitialized checking for
arrays * first check uninitialized status of right side of assignment
before setting the left side to "written" (-> catch "x:=x" if x is
uninitialized)
git-svn-id: trunk@2038 -
---
compiler/htypechk.pas | 7 +++++--
compiler/nld.pas | 2 +-
compiler/nmem.pas | 22 +++++++++++++++-------
3 files changed, 21 insertions(+), 10 deletions(-)
diff --git a/compiler/htypechk.pas b/compiler/htypechk.pas
index 0fadb8cc1a..8f0689ecfa 100644
--- a/compiler/htypechk.pas
+++ b/compiler/htypechk.pas
@@ -773,8 +773,11 @@ implementation
vecn:
begin
set_varstate(tbinarynode(p).right,vs_read,[vsf_must_be_valid]);
- if not(tunarynode(p).left.resulttype.def.deftype in [stringdef,arraydef]) then
- include(varstateflags,vsf_must_be_valid);
+ if (newstate in [vs_read,vs_readwritten]) or
+ not(tunarynode(p).left.resulttype.def.deftype in [stringdef,arraydef]) then
+ include(varstateflags,vsf_must_be_valid)
+ else if (newstate = vs_written) then
+ exclude(varstateflags,vsf_must_be_valid);
p:=tunarynode(p).left;
end;
{ do not parse calln }
diff --git a/compiler/nld.pas b/compiler/nld.pas
index bd8f9dc6ae..98e0777886 100644
--- a/compiler/nld.pas
+++ b/compiler/nld.pas
@@ -564,8 +564,8 @@ implementation
end;
resulttypepass(right);
- set_varstate(left,vs_written,[]);
set_varstate(right,vs_read,[vsf_must_be_valid]);
+ set_varstate(left,vs_written,[]);
if codegenerror then
exit;
diff --git a/compiler/nmem.pas b/compiler/nmem.pas
index 37ca6d6473..6ca4119648 100644
--- a/compiler/nmem.pas
+++ b/compiler/nmem.pas
@@ -443,9 +443,12 @@ implementation
{ this is like the function addr }
inc(parsing_para_level);
- { this is actually only "read", but treat it nevertheless as modified }
- { due to the possible use of pointers }
- set_varstate(left,vs_readwritten,[]);
+ { This is actually only "read", but treat it nevertheless as }
+ { modified due to the possible use of pointers }
+ { To avoid false positives regarding "uninitialised" }
+ { warnings when using arrays, perform it in two steps }
+ set_varstate(left,vs_written,[]);
+ set_varstate(left,vs_read,[]);
dec(parsing_para_level);
end;
@@ -660,11 +663,16 @@ implementation
ansi/widestring needs to be valid }
valid:=is_dynamic_array(left.resulttype.def) or
is_ansistring(left.resulttype.def) or
- is_widestring(left.resulttype.def);
+ is_widestring(left.resulttype.def) or
+ { implicit pointer dereference -> pointer is read }
+ (left.resulttype.def.deftype = pointerdef);
if valid then
- set_varstate(left,vs_read,[vsf_must_be_valid])
- else
- set_varstate(left,vs_read,[]);
+ set_varstate(left,vs_read,[vsf_must_be_valid]);
+{
+ A vecn is, just like a loadn, always part of an expression with its
+ own read/write and must_be_valid semantics. Therefore we don't have
+ to do anything else here, just like for loadn's
+}
set_varstate(right,vs_read,[vsf_must_be_valid]);
if codegenerror then
exit;