C generator: fix code generation for if stmt and multi-decl

* wrap `if` statement with declaration in condition in a block
* generate single statement for multi-declarations
* add tests

Author: chqrlie

generator/c/c2i_generator_stmt.c2

@@ -187,18 +187,21 @@ fn void Generator.emitStmt(Generator* gen, ast.Stmt* s, u32 indent, bool newline
             VarDecl* vd = ds.getDecl(i);
             Decl* d = cast<Decl*>(vd);
 
-            // TODO: combine into a single statement
             //if (vd.hasLocalQualifier()) out.add("local ");
-            gen.emitTypeRef(vd.getTypeRef());
+            if (i == 0) {
+                gen.emitTypeRef(vd.getTypeRef());
+            } else {
+                out.add1(',');
+            }
             out.space();
             out.add(d.getName());
             const Expr* ie = vd.getInit();
             if (ie) {
                 out.add(" = ");
                 gen.emitExpr(ie);
             }
-            if (newline) out.add(";\n");
         }
+        if (newline) out.add(";\n");
         break;
     case Asm:
         //gen.emitAsmStmt(cast<AsmStmt*>(s), indent);

generator/c/c_generator_stmt.c2

@@ -19,17 +19,22 @@ import ast local;
 import source_mgr;
 import string_buffer;
 
-fn void Generator.emitVarDecl(Generator* gen, VarDecl* vd, string_buffer.Buf* out, bool emit_init) {
+fn void Generator.emitVarDecl(Generator* gen, VarDecl* vd, string_buffer.Buf* out, bool emit_init, bool first) {
     Decl* d = cast<Decl*>(vd);
-    if (vd.hasLocalQualifier()) out.add("static ");
-    gen.emitTypePre(out, d.getType());
+    if (first) {
+        if (vd.hasLocalQualifier()) out.add("static ");
+        gen.emitTypePre(out, d.getType());
+    } else {
+        out.add1(',');
+    }
     out.space();
     out.add(d.getName());
     gen.emitTypePost(out, d.getType());
     d.setGenerated();
     Expr* ie = vd.getInit();
     if (ie && emit_init) {
         if (vd.hasInitCall()) {
+            assert(first);
             out.add("; ");
         } else {
             out.add(" = ");
@@ -66,8 +71,10 @@ fn void Generator.emitStmt(Generator* gen, Stmt* s, u32 indent, bool newline) {
         Stmt* cond = i.getCond();
         bool is_decl = cond.isDecl();
         if (is_decl) {
+            out.add("{\n");
+            indent++;
             // TODO leave out init part
-            gen.emitStmt(cond, 0, true);
+            gen.emitStmt(cond, indent, true);
             out.indent(indent);
             out.add("if (");
             DeclStmt* ds = cast<DeclStmt*>(cond);
@@ -100,6 +107,11 @@ fn void Generator.emitStmt(Generator* gen, Stmt* s, u32 indent, bool newline) {
             }
         }
         out.newline();
+        if (is_decl) {
+            indent--;
+            out.indent(indent);
+            out.add("}\n");
+        }
         break;
     case While:
         WhileStmt* w = cast<WhileStmt*>(s);
@@ -111,7 +123,7 @@ fn void Generator.emitStmt(Generator* gen, Stmt* s, u32 indent, bool newline) {
             DeclStmt* ds = cast<DeclStmt*>(cond);
             VarDecl* vd = ds.getDecl(0);
             out.indent(indent);
-            gen.emitVarDecl(vd, out, false);
+            gen.emitVarDecl(vd, out, false, true);
             out.add(";\n");
             out.indent(indent);
             out.add("while (");
@@ -215,11 +227,13 @@ fn void Generator.emitStmt(Generator* gen, Stmt* s, u32 indent, bool newline) {
     case Decl:
         DeclStmt* ds = cast<DeclStmt*>(s);
         u32 count = ds.getDeclCount();
+        bool first = true;
         for (u32 i = 0; i < count; i++) {
             VarDecl* vd = ds.getDecl(i);
-            gen.emitVarDecl(vd, out, true);
-            if (newline) out.add(";\n");
+            gen.emitVarDecl(vd, out, true, first);
+            first = false;
         }
+        if (newline) out.add(";\n");
         break;
     case Asm:
         gen.emitAsmStmt(cast<AsmStmt*>(s), indent);

test/c_generator/stmts/if_stmt_expr.c2t

@@ -9,12 +9,14 @@ public fn i32 main(i32 argc, const char** argv) {
     i32 a = 0;
     if (a) {}
 
-    if (i32 b = 10) {
-
-    }
+    if (a)
+        if (i32 b = 10)
+            return 0;
+        else
+            return 1;
 
     if (true) {
-
+        return 2;
     }
 
     return 0;
@@ -28,11 +30,14 @@ int32_t main(int32_t argc, const char** argv)
     if (a) {
     }
 
-    int32_t b = 10;
-    if (b) {
+    if (a) {
+        int32_t b = 10;
+        if (b) return 0;
+        else return 1;
     }
 
     if (true) {
+        return 2;
     }
 
     return 0;

test/c_generator/stmts/multi_def.c2t

@@ -0,0 +1,68 @@
+// @recipe bin
+    $warnings no-unused
+    $backend c
+
+// @file{file1}
+module test;
+
+type Point struct {
+    i32 x, y;
+}
+
+fn void Point.print(const Point* p) {
+    //printf("{ %d, %d }\n", p.x, p.y);
+}
+
+fn void test1(i32 i) {}
+
+public fn i32 main() {
+    i32 x = 1, y = 2;
+
+    Point p1 = { 1, 2 }, p2 = { 3, 4 };
+
+    if (x > y)
+        if (i32 z = 1)
+            p1.print();
+        else
+            p2.print();
+
+    for (i32 i = 0, n = 32; i < n; i++)
+        test1(i);
+
+    return 0;
+}
+
+// @expect{atleast, cgen/build.c}
+
+typedef struct test_Point_ test_Point;
+
+struct test_Point_ {
+   int32_t x;
+   int32_t y;
+};
+
+static void test_Point_print(const test_Point* p);
+static void test_test1(int32_t i);
+int32_t main(void);
+
+static void test_Point_print(const test_Point* p)
+{
+}
+
+static void test_test1(int32_t i)
+{
+}
+
+int32_t main(void)
+{
+   int32_t x = 1, y = 2;
+   test_Point p1 = { 1, 2 }, p2 = { 3, 4 };
+   if ((x > y)) {
+      int32_t z = 1;
+      if (z) test_Point_print(&p1);
+      else test_Point_print(&p2);
+   }
+
+   for (int32_t i = 0, n = 32; (i < n); i++) test_test1(i);
+   return 0;
+}