Support PIE (Position Independent Executables)

Closes #4503
Revives #3960
Merges branch 'pie' into master

4 files changed, 12 insertions, 0 deletions

diff --git a/src/stage1/all_types.hpp b/src/stage1/all_types.hpp
index d56bcffff1..957a377b6d 100644
--- a/src/stage1/all_types.hpp
+++ b/src/stage1/all_types.hpp
@@ -2177,6 +2177,7 @@ struct CodeGen {
     bool is_test_build;
     bool is_single_threaded;
     bool have_pic;
+    bool have_pie;
     bool link_mode_dynamic;
     bool dll_export_fns;
     bool have_stack_probing;
diff --git a/src/stage1/codegen.cpp b/src/stage1/codegen.cpp
index 26fe00228e..d0bb9b4411 100644
--- a/src/stage1/codegen.cpp
+++ b/src/stage1/codegen.cpp
@@ -9043,6 +9043,7 @@ Buf *codegen_generate_builtin_source(CodeGen *g) {
     buf_appendf(contents, "pub const have_error_return_tracing = %s;\n", bool_to_str(g->have_err_ret_tracing));
     buf_appendf(contents, "pub const valgrind_support = false;\n");
     buf_appendf(contents, "pub const position_independent_code = %s;\n", bool_to_str(g->have_pic));
+    buf_appendf(contents, "pub const position_independent_executable = %s;\n", bool_to_str(g->have_pie));
     buf_appendf(contents, "pub const strip_debug_info = %s;\n", bool_to_str(g->strip_debug_symbols));
     buf_appendf(contents, "pub const code_model = CodeModel.default;\n");
 
@@ -9170,6 +9171,14 @@ static void init(CodeGen *g) {
         reloc_mode = LLVMRelocStatic;
     }
 
+    if (g->have_pic) {
+        ZigLLVMSetModulePICLevel(g->module);
+    }
+
+    if (g->have_pie) {
+        ZigLLVMSetModulePIELevel(g->module);
+    }
+
     const char *target_specific_cpu_args = "";
     const char *target_specific_features = "";
 
diff --git a/src/stage1/stage1.cpp b/src/stage1/stage1.cpp
index 1034f9ff88..fec6760623 100644
--- a/src/stage1/stage1.cpp
+++ b/src/stage1/stage1.cpp
@@ -89,6 +89,7 @@ void zig_stage1_build_object(struct ZigStage1 *stage1) {
     g->link_mode_dynamic = stage1->link_mode_dynamic;
     g->dll_export_fns = stage1->dll_export_fns;
     g->have_pic = stage1->pic;
+    g->have_pie = stage1->pie;
     g->have_stack_probing = stage1->enable_stack_probing;
     g->is_single_threaded = stage1->is_single_threaded;
     g->valgrind_enabled = stage1->valgrind_enabled;
diff --git a/src/stage1/stage1.h b/src/stage1/stage1.h
index 412118a6fa..0552aa09e0 100644
--- a/src/stage1/stage1.h
+++ b/src/stage1/stage1.h
@@ -177,6 +177,7 @@ struct ZigStage1 {
     enum ErrColor err_color;
 
     bool pic;
+    bool pie;
     bool link_libc;
     bool link_libcpp;
     bool strip;