vm: maintain export symbol tables per program

Instead of having one global export table per VM instance maintain one table
per program instance. This is required to avoid clobbering the export list
in case `import` using code is loaded at runtime through `require()`,
`loadfile()` etc.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 143 insertions, 0 deletions

diff --git a/tests/custom/04_modules/16_multi_program_imports b/tests/custom/04_modules/16_multi_program_imports
new file mode 100644
index 0000000..32d54fe
--- /dev/null
+++ b/tests/custom/04_modules/16_multi_program_imports
@@ -0,0 +1,143 @@
+This testcase asserts that import/export symbols in runtime loaded code
+are properly dealt with.
+
+Since the compiler has no knowledge about runtime loaded code it cannot
+reserve slots in the export table, requiring the VM to maintain one export
+table per program instance.
+
+The dependency tree is:
+
+root
+ + import: mod1
+ + import: mod2
+ + require: mod3
+    + import: mod1
+    + import: mod2
+
+-- Testcase --
+import { mod2sym1, mod2sym2 } from 'mod2';
+import { mod1sym1, mod1sym2 } from 'mod1';
+
+mod3 = require('mod3');
+
+printf("root: %.J\n", { mod1sym1, mod1sym2, mod2sym1, mod2sym2, mod3 });
+-- End --
+
+-- File mod1.uc --
+export const mod1sym1 = "a";
+export const mod1sym2 = "b";
+-- End --
+
+-- File mod2.uc --
+export const mod2sym1 = "c";
+export const mod2sym2 = "d";
+-- End --
+
+-- File mod3.uc --
+import { mod1sym2, mod1sym1 } from 'mod1';
+import { mod2sym2, mod2sym1 } from 'mod2';
+
+printf("mod3: %.J\n", { mod1sym1, mod1sym2, mod2sym1, mod2sym2 });
+
+return { mod1sym1, mod1sym2, mod2sym1, mod2sym2 };
+-- End --
+
+-- Args --
+-R -L files/
+-- End --
+
+-- Expect stdout --
+mod3: {
+	"mod1sym1": "a",
+	"mod1sym2": "b",
+	"mod2sym1": "c",
+	"mod2sym2": "d"
+}
+root: {
+	"mod1sym1": "a",
+	"mod1sym2": "b",
+	"mod2sym1": "c",
+	"mod2sym2": "d",
+	"mod3": {
+		"mod1sym1": "a",
+		"mod1sym2": "b",
+		"mod2sym1": "c",
+		"mod2sym2": "d"
+	}
+}
+-- End --
+
+
+A variation of the above testcase using wildcard imports.
+
+root
+ + import: mod4
+ + import: mod5
+ + require: mod6
+    + import: mod4
+    + import: mod5
+
+-- Testcase --
+import * as mod5 from 'mod5';
+import * as mod4 from 'mod4';
+
+mod6 = require('mod6');
+
+printf("root: %.J\n", { mod4, mod5, mod6 });
+-- End --
+
+-- File mod4.uc --
+export const sym1 = "a";
+export const sym2 = "b";
+-- End --
+
+-- File mod5.uc --
+export const sym1 = "c";
+export const sym2 = "d";
+-- End --
+
+-- File mod6.uc --
+import * as mod4 from 'mod4';
+import * as mod5 from 'mod5';
+
+printf("mod6: %.J\n", { mod4, mod5 });
+
+return { mod4, mod5 };
+-- End --
+
+-- Args --
+-R -L files/
+-- End --
+
+-- Expect stdout --
+mod6: {
+	"mod4": {
+		"sym1": "a",
+		"sym2": "b"
+	},
+	"mod5": {
+		"sym1": "c",
+		"sym2": "d"
+	}
+}
+root: {
+	"mod4": {
+		"sym1": "a",
+		"sym2": "b"
+	},
+	"mod5": {
+		"sym1": "c",
+		"sym2": "d"
+	},
+	"mod6": {
+		"mod4": {
+			"sym1": "a",
+			"sym2": "b"
+		},
+		"mod5": {
+			"sym1": "c",
+			"sym2": "d"
+		}
+	}
+}
+-- End --