MC: add support for -aligncomm GNU extension

The GNU linker supports an -aligncomm directive that allows for power-of-2
alignment of common data.  Add support to emit this directive.

llvm-svn: 219229

1 files changed, 50 insertions, 0 deletions

diff --git a/llvm/test/MC/COFF/comm-align.s b/llvm/test/MC/COFF/comm-align.s
new file mode 100644
index 00000000000..e658c5685d3
--- /dev/null
+++ b/llvm/test/MC/COFF/comm-align.s
@@ -0,0 +1,50 @@
+# RUN: llvm-mc -triple i686-windows-gnu -filetype obj -o - %s \
+# RUN:    | llvm-readobj -coff-directives -symbols | FileCheck %s
+
+# NOTE: this test checks multiple things:
+# - that -aligncomm is not emitted for 1-byte alignment
+# - that -aligncomm is emitted for the various alignments (greater than 1)
+# - that the alignment is represented as a log_2 of the alignment
+# - that the section switching occurs correctly
+# - that functions after the switch also are emitted into the correct section
+
+	.text
+
+	.def _a
+		.scl 3
+		.type 32
+	.endef
+_a:
+	ret
+
+	.data
+
+	.comm _s_1,4,0                  # @s_1
+	.comm _s_2,4,1                  # @s_2
+	.comm _s_4,4,2                  # @s_3
+	.comm _s_8,4,3                  # @s_4
+
+	.text
+
+	.def _b
+		.scl 3
+		.type 32
+	.endef
+_b:
+	ret
+
+# CHECK-NOT: -aligncomm:"_s_1",0
+
+# CHECK: Symbols [
+# CHECK:   Symbol {
+# CHECK:     Name: _a
+# CHECK:     Section: .text (1)
+# CHECK:   }
+# CHECK:   Symbol {
+# CHECK:     Name: _b
+# CHECK:     Section: .text (1)
+# CHECK:   }
+# CHECK: ]
+
+# CHECK: Directive(s): -aligncomm:"_s_2",1 -aligncomm:"_s_4",2 -aligncomm:"_s_8",3
+