[m-rev.] diff: fix bug #229

[Peter Wang]

Will commit pending bootcheck.

Branches: main, 11.07

Fix bug #229.  A term with an argument produced in a from_ground_term_construct
scope was not itself being marked to be constructed statically.  A side-effect
was an exception being thrown while generating a lookup switch in high-level C
grades.

compiler/mark_static_terms.m:
	Add the variable constructed in a from_ground_term_construct scope
	to the set of static variables.

tests/valid/Mercury.options:
tests/valid/mark_static_bug.m:
	Add test case.

diff --git a/compiler/mark_static_terms.m b/compiler/mark_static_terms.m
index 9e0602e..9e8003a 100644
--- a/compiler/mark_static_terms.m
+++ b/compiler/mark_static_terms.m
@@ -67,7 +67,7 @@ goal_mark_static_terms(Goal0, Goal, !SI) :-
         GoalExpr0 = conj(ConjType, Goals0),
         % It's OK to treat parallel conjunctions as if they were sequential
         % here, since if we mark any variables as static, the computation
-        %of those variables will be done at compile time.
+        % of those variables will be done at compile time.
         conj_mark_static_terms(Goals0, Goals, !SI),
         GoalExpr = conj(ConjType, Goals)
     ;
@@ -87,9 +87,10 @@ goal_mark_static_terms(Goal0, Goal, !SI) :-
         GoalExpr = negation(SubGoal)
     ;
         GoalExpr0 = scope(Reason, SubGoal0),
-        ( Reason = from_ground_term(_TermVar, from_ground_term_construct) ->
+        ( Reason = from_ground_term(TermVar, from_ground_term_construct) ->
             % These scopes already have all their unifications marked
             % as construct_statically.
+            set_tree234.insert(TermVar, !SI),
             GoalExpr = GoalExpr0
         ;
             goal_mark_static_terms(SubGoal0, SubGoal, !SI),
diff --git a/tests/valid/Mercury.options b/tests/valid/Mercury.options
index 9b84a3b..c50d775 100644
--- a/tests/valid/Mercury.options
+++ b/tests/valid/Mercury.options
@@ -112,6 +112,7 @@ MCFLAGS-livevars_shallow	= --no-intermodule-optimization --grade none --trace sh
 MCFLAGS-livevars_shallow2	= --no-intermodule-optimization --grade none --trace shallow
 MCFLAGS-lco_term		= --optimize-constructor-last-call
 MCFLAGS-loop_inv_bug		= --common-struct --loop-invariants
+MCFLAGS-mark_static_bug		= --lookup-switch-size 1
 MCFLAGS-mc_bag			= --prop-mode-constraints
 MCFLAGS-mc_extra_nonlocals	= --prop-mode-constraints
 MCFLAGS-mc_graph		= --prop-mode-constraints
diff --git a/tests/valid/mark_static_bug.m b/tests/valid/mark_static_bug.m
new file mode 100644
index 0000000..cd8d284
--- /dev/null
+++ b/tests/valid/mark_static_bug.m
@@ -0,0 +1,39 @@
+% A term with an argument produced in a from_ground_term_construct scope was
+% not itself being marked to be constructed statically.  A side-effect was an
+% exception being thrown while generating a lookup switch in high-level C
+% grades.
+
+:- module mark_static_bug.
+:- interface.
+
+:- type foo
+    --->    foo(int, bar).
+
+:- type bar
+    --->    none
+    ;       bar(int, int, int, baz).
+
+:- type baz
+    --->    baz(int).
+
+:- pred mkfoo(int::in, foo::out) is semidet.
+
+:- implementation.
+
+mkfoo(X, Foo) :-
+    (
+        X = 1,
+        Bar = bar(100, 200, 300, baz(400)),
+        Foo = foo(1, Bar)
+    ;
+        X = 2,
+        Foo = foo(2, none)
+    ;
+        X = 3,
+        Foo = foo(3, none)
+    ;
+        X = 4,
+        Foo = foo(4, none)
+    ).
+
+% vim: ft=mercury ts=4 sts=4 sw=4 et

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