Emit word of zeroes after the last instruction as a start of the mandatory

traceback table on PowerPC64. This helps gdb handle exceptions. The other
mandatory fields are ignored by gdb and harder to implement so just add
there a FIXME.

Patch by Bill Schmidt. PR13641.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162778 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/PowerPC/PPCAsmPrinter.cpp

@@ -109,6 +109,8 @@ namespace {
     bool doFinalization(Module &M);
 
     virtual void EmitFunctionEntryLabel();
+
+    void EmitFunctionBodyEnd();
   };
 
   /// PPCDarwinAsmPrinter - PowerPC assembly printer, customized for Darwin/Mac
@@ -450,6 +452,19 @@ bool PPCLinuxAsmPrinter::doFinalization(Module &M) {
   return AsmPrinter::doFinalization(M);
 }
 
+/// EmitFunctionBodyEnd - Print the traceback table before the .size
+/// directive.
+///
+void PPCLinuxAsmPrinter::EmitFunctionBodyEnd() {
+  // Only the 64-bit target requires a traceback table.  For now,
+  // we only emit the word of zeroes that GDB requires to find
+  // the end of the function.
+  // FIXME: Eventually we should add the eight-byte mandatory fields
+  // described in the PPC64 ELF ABI.
+  if (Subtarget.isPPC64())
+    OutStreamer.EmitIntValue(0, 4/*size*/);
+}
+
 void PPCDarwinAsmPrinter::EmitStartOfAsmFile(Module &M) {
   static const char *const CPUDirectives[] = {
     "",

test/CodeGen/PowerPC/pr13641.ll

@@ -0,0 +1,10 @@
+; RUN: llc < %s | FileCheck %s
+target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v128:128:128-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+
+define void @foo() nounwind {
+  ret void
+}
+
+; CHECK: blr
+; CHECK-NEXT: .long 0