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cgen: optimize out the empty #ifdef NOT_CURRENT_TARGET_OS #endif output

This commit is contained in:
Delyan Angelov 2021-04-02 18:52:30 +03:00
parent 6a5f49afb1
commit 53cbdbc2de
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@ -6,6 +6,7 @@ module c
import os
import v.ast
import v.util
import v.pref
fn (mut g Gen) comptime_selector(node ast.ComptimeSelector) {
g.expr(node.left)
@ -188,6 +189,27 @@ fn (mut g Gen) comp_at(node ast.AtExpr) {
}
fn (mut g Gen) comp_if(node ast.IfExpr) {
if !node.is_expr && !node.has_else && node.branches.len == 1 {
if node.branches[0].stmts.len == 0 {
// empty ifdef; result of target OS != conditional => skip
return
}
if !g.pref.output_cross_c {
if node.branches[0].cond is ast.Ident {
if g.pref.os == (pref.os_from_string(node.branches[0].cond.name) or {
pref.OS._auto
}) {
// Same target OS as the conditional...
// => skip the #if defined ... #endif wrapper
// and just generate the branch statements:
g.indent--
g.stmts(node.branches[0].stmts)
g.indent++
return
}
}
}
}
line := if node.is_expr {
stmt_str := g.go_before_stmt(0)
g.write(util.tabs(g.indent))