[macho] save the SDK version stored in module metadata into the version min and

build version load commands in the object file

This commit introduces a new metadata node called "SDK Version". It will be set
by the frontend to mark the platform SDK (macOS/iOS/etc) version which was used
during that particular compilation.
This node is used when machine code is emitted, by either saving the SDK version
into the appropriate macho load command (version min/build version), or by
emitting the assembly for these load commands with the SDK version specified as
well.
The assembly for both load commands is extended by allowing it to contain the
sdk_version X, Y [, Z] trailing directive to represent the SDK version
respectively.

rdar://45774000

Differential Revision: https://reviews.llvm.org/D55612

llvm-svn: 349119

1 files changed, 21 insertions, 4 deletions

diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index 463e9066616..0daec983dfd 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -147,9 +147,9 @@ public:
   void EmitLinkerOptions(ArrayRef<std::string> Options) override;
   void EmitDataRegion(MCDataRegionType Kind) override;
   void EmitVersionMin(MCVersionMinType Kind, unsigned Major, unsigned Minor,
-                      unsigned Update) override;
+                      unsigned Update, VersionTuple SDKVersion) override;
   void EmitBuildVersion(unsigned Platform, unsigned Major, unsigned Minor,
-                        unsigned Update) override;
+                        unsigned Update, VersionTuple SDKVersion) override;
   void EmitThumbFunc(MCSymbol *Func) override;
 
   void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) override;
@@ -514,11 +514,26 @@ static const char *getVersionMinDirective(MCVersionMinType Type) {
   llvm_unreachable("Invalid MC version min type");
 }
 
+static void EmitSDKVersionSuffix(raw_ostream &OS,
+                                 const VersionTuple &SDKVersion) {
+  if (SDKVersion.empty())
+    return;
+  OS << '\t' << "sdk_version " << SDKVersion.getMajor();
+  if (auto Minor = SDKVersion.getMinor()) {
+    OS << ", " << *Minor;
+    if (auto Subminor = SDKVersion.getSubminor()) {
+      OS << ", " << *Subminor;
+    }
+  }
+}
+
 void MCAsmStreamer::EmitVersionMin(MCVersionMinType Type, unsigned Major,
-                                   unsigned Minor, unsigned Update) {
+                                   unsigned Minor, unsigned Update,
+                                   VersionTuple SDKVersion) {
   OS << '\t' << getVersionMinDirective(Type) << ' ' << Major << ", " << Minor;
   if (Update)
     OS << ", " << Update;
+  EmitSDKVersionSuffix(OS, SDKVersion);
   EmitEOL();
 }
 
@@ -534,11 +549,13 @@ static const char *getPlatformName(MachO::PlatformType Type) {
 }
 
 void MCAsmStreamer::EmitBuildVersion(unsigned Platform, unsigned Major,
-                                     unsigned Minor, unsigned Update) {
+                                     unsigned Minor, unsigned Update,
+                                     VersionTuple SDKVersion) {
   const char *PlatformName = getPlatformName((MachO::PlatformType)Platform);
   OS << "\t.build_version " << PlatformName << ", " << Major << ", " << Minor;
   if (Update)
     OS << ", " << Update;
+  EmitSDKVersionSuffix(OS, SDKVersion);
   EmitEOL();
 }