[llvm-mc] - Teach llvm-mc to generate zlib styled compression sections.

This patch is strongly based on previously reverted D20331.
(because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style)

Difference that this patch supports both zlib and zlib-gnu styles.

-compress-debug-sections option now supports next values:

-compress-debug-sections=zlib-gnu
-compress-debug-sections=zlib
-compress-debug-sections=none
Previously specifying -compress-debug-sections enabled zlib-gnu compression,
so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior
that was before this patch for case when compression was enabled.

Differential revision: http://reviews.llvm.org/D20676

llvm-svn: 270977

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/MC/MCAsmInfo.cpp b/llvm/lib/MC/MCAsmInfo.cpp
index fa7d438d159..fa83e395f8d 100644
--- a/llvm/lib/MC/MCAsmInfo.cpp
+++ b/llvm/lib/MC/MCAsmInfo.cpp
@@ -108,7 +108,7 @@ MCAsmInfo::MCAsmInfo() {
   //   - The target subclasses for AArch64, ARM, and X86 handle these cases
   UseIntegratedAssembler = false;
 
-  CompressDebugSections = false;
+  CompressDebugSections = DebugCompressionType::DCT_None;
 }
 
 MCAsmInfo::~MCAsmInfo() {