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cgen: materialise str-def operands in streq pushes

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A str `def` has no name(SB) header; the streq push arms read a frame
slot that does not exist. Load the literal through cgexpr (AX=ptr,
BX=len) instead. Both stages.
This commit is contained in:
Hojun-Cho
2026-08-07 22:59:47 +09:00
parent 0bb1f86c14
commit c654e97db1
3 changed files with 38 additions and 0 deletions
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10
cmd/w6c/cgen.c
View File

@@ -4925,6 +4925,12 @@ cgexpr(Cg *c, Node *n, Local *locals)
ins1(c, A_PUSHQ, areg(D_AX)); ins1(c, A_PUSHQ, areg(D_AX));
ins2(c, A_MOVQ, amem(D_BX, 0), areg(D_AX)); ins2(c, A_MOVQ, amem(D_BX, 0), areg(D_AX));
ins1(c, A_PUSHQ, areg(D_AX)); ins1(c, A_PUSHQ, areg(D_AX));
} else if (off == 0 && def_isanydef(n->rhs->str)) {
/* A str `def` has no name(SB) header: cgexpr
* materialises its literal as AX=ptr, BX=len. */
cgexpr(c, n->rhs, locals);
ins1(c, A_PUSHQ, areg(D_BX));
ins1(c, A_PUSHQ, areg(D_AX));
} else { } else {
ins2(c, A_MOVQ, amem(D_BP, off + 8), areg(D_AX)); ins2(c, A_MOVQ, amem(D_BP, off + 8), areg(D_AX));
ins1(c, A_PUSHQ, areg(D_AX)); ins1(c, A_PUSHQ, areg(D_AX));
@@ -4948,6 +4954,10 @@ cgexpr(Cg *c, Node *n, Local *locals)
ins1(c, A_PUSHQ, areg(D_AX)); ins1(c, A_PUSHQ, areg(D_AX));
ins2(c, A_MOVQ, amem(D_BX, 0), areg(D_AX)); ins2(c, A_MOVQ, amem(D_BX, 0), areg(D_AX));
ins1(c, A_PUSHQ, areg(D_AX)); ins1(c, A_PUSHQ, areg(D_AX));
} else if (off == 0 && def_isanydef(n->lhs->str)) {
cgexpr(c, n->lhs, locals);
ins1(c, A_PUSHQ, areg(D_BX));
ins1(c, A_PUSHQ, areg(D_AX));
} else { } else {
ins2(c, A_MOVQ, amem(D_BP, off + 8), areg(D_AX)); ins2(c, A_MOVQ, amem(D_BP, off + 8), areg(D_AX));
ins1(c, A_PUSHQ, areg(D_AX)); ins1(c, A_PUSHQ, areg(D_AX));

8
selfhost/cmd/wcc/cgenexpr.ww
View File

@@ -5808,6 +5808,14 @@ fn cgstreqpush(c: *cgen, op: *syntax.node) void = {
emitline("\tPUSHQ\tAX\n"); emitline("\tPUSHQ\tAX\n");
return; return;
}; };
if (lc == nil && deflookup(c, nm)) {
// A str def has no name(SB) header. Its ordinary expression
// load materialises the literal as AX=ptr, BX=len.
cgexpr(c, op);
emitline("\tPUSHQ\tBX\n");
emitline("\tPUSHQ\tAX\n");
return;
};
let off: i32 = 0; let off: i32 = 0;
if (lc != nil) { off = lc.off; }; if (lc != nil) { off = lc.off; };
emitline("\tMOVQ\t"); emitline("\tMOVQ\t");

20
test/lang/str_def_equality_test.ww Normal file
View File

@@ -0,0 +1,20 @@
// String equality must materialise a module def literal instead of treating
// its name as a frame-local string header. Use a duplicated local so pointer
// equality cannot accidentally satisfy the content comparison.
package str_def_equality_test;
import strings;
def expected: str = "dynamic string versus def";
@test fn dynamic_string_and_def_compare_by_content() void = {
let observed: str = strings.dup(expected);
assert(observed == expected);
assert(expected == observed);
assert(!(observed != expected));
assert(!(expected != observed));
let different: str = strings.concat(observed, "!");
assert(different != expected);
assert(expected != different);
};