Recommit "[MS] Improved implementation of stack pragmas (vtordisp, *_seg)"

Slightly updated version, double-checked build and tests.
Improve implementation of MS pragmas that use stack + compatibility fixes.
This patch:
  1. Changes implementation of #pragma vtordisp to use PragmaStack class
     that other stack pragmas use;
  2. Fixes "#pragma vtordisp()" behavior - it shouldn't affect the stack;
  3. Supports "save-restore" of pragma stacks on enter / exit a C++ method
     body, as MSVC does.

TODO:
  1. Change implementation of #pragma pack to use the same approach;
  2. Introduce diagnostics on popping named stack slots, as MSVC does.

Reviewers:
  rnk, thakis

Differential revision: http://reviews.llvm.org/D19361

llvm-svn: 268029

1 files changed, 29 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/sections.cpp b/clang/test/CodeGenCXX/sections.cpp
index bec2e2d3d70..c33871a97f5 100644
--- a/clang/test/CodeGenCXX/sections.cpp
+++ b/clang/test/CodeGenCXX/sections.cpp
@@ -31,6 +31,31 @@ int TEST1;
 #pragma bss_seg(pop)
 int TEST2;
 
+
+// Check "save-restore" of pragma stacks.
+struct Outer {
+  void f() {
+    #pragma bss_seg(push, ".bss3")
+    #pragma code_seg(push, ".my_code1")
+    #pragma const_seg(push, ".my_const1")
+    #pragma data_seg(push, ".data3")
+    struct Inner {
+      void g() {
+        #pragma bss_seg(push, ".bss4")
+        #pragma code_seg(push, ".my_code2")
+        #pragma const_seg(push, ".my_const2")
+        #pragma data_seg(push, ".data4")
+      }
+    };
+  }
+};
+
+void h2(void) {} // should be in ".my_code"
+int TEST3; // should be in ".bss1"
+int d2 = 1; // should be in ".data"
+extern const int b2; // should be in ".my_const"
+const int b2 = 1;
+
 #pragma section("read_flag_section", read)
 // Even though they are not declared const, these become constant since they are
 // in a read-only section.
@@ -63,6 +88,9 @@ __declspec(allocate("short_section")) short short_var = 42;
 //CHECK: @i = global i32 0
 //CHECK: @TEST1 = global i32 0
 //CHECK: @TEST2 = global i32 0, section ".bss1"
+//CHECK: @TEST3 = global i32 0, section ".bss1"
+//CHECK: @d2 = global i32 1, section ".data"
+//CHECK: @b2 = constant i32 1, section ".my_const"
 //CHECK: @unreferenced = constant i32 0, section "read_flag_section"
 //CHECK: @referenced = constant i32 42, section "read_flag_section"
 //CHECK: @implicitly_read_write = global i32 42, section "no_section_attributes"
@@ -70,3 +98,4 @@ __declspec(allocate("short_section")) short short_var = 42;
 //CHECK: @short_var = global i16 42, section "short_section"
 //CHECK: define void @g()
 //CHECK: define void @h() {{.*}} section ".my_code"
+//CHECK: define void @h2() {{.*}} section ".my_code"