[XRay][Arm] Repair XRay table emission on Arm32 and add tests to identify such problem earlier

Summary:
Emission of XRay table was occasionally disabled for Arm32, but this bug was not then detected because earlier (also by mistake) testing of XRay was occasionally disabled on 32-bit Arm targets. This patch should fix that problem and detect such problems in the future.
This patch is one of a series, see also
- https://reviews.llvm.org/D28623

Reviewers: rengolin, dberris

Reviewed By: dberris

Subscribers: llvm-commits, aemerson, rengolin, dberris, iid_iunknown

Differential Revision: https://reviews.llvm.org/D28624

llvm-svn: 292516

llvm/lib/Target/ARM/ARMAsmPrinter.cpp

@@ -164,6 +164,9 @@ bool ARMAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
   // Emit the rest of the function body.
   EmitFunctionBody();
 
+  // Emit the XRay table for this function.
+  emitXRayTable();
+
   // If we need V4T thumb mode Register Indirect Jump pads, emit them.
   // These are created per function, rather than per TU, since it's
   // relatively easy to exceed the thumb branch range within a TU.

llvm/test/CodeGen/ARM/xray-armv6-attribute-instrumentation.ll

@@ -23,3 +23,9 @@ define i32 @foo() nounwind noinline uwtable "function-instrument"="xray-always"
 ; CHECK-LABEL: Ltmp1:
 ; CHECK-NEXT:  bx	lr
 }
+; CHECK:       .p2align 4
+; CHECK-NEXT:  .long {{.*}}Lxray_synthetic_0
+; CHECK-NEXT:  .section {{.*}}xray_instr_map{{.*}}
+; CHECK-LABEL: Lxray_synthetic_0:
+; CHECK:       .long {{.*}}Lxray_sled_0
+; CHECK:       .long {{.*}}Lxray_sled_1

llvm/test/CodeGen/ARM/xray-armv7-attribute-instrumentation.ll

@@ -23,3 +23,9 @@ define i32 @foo() nounwind noinline uwtable "function-instrument"="xray-always"
 ; CHECK-LABEL: Ltmp1:
 ; CHECK-NEXT:  bx lr
 }
+; CHECK:       .p2align 4
+; CHECK-NEXT:  .long {{.*}}Lxray_synthetic_0
+; CHECK-NEXT:  .section {{.*}}xray_instr_map{{.*}}
+; CHECK-LABEL: Lxray_synthetic_0:
+; CHECK:       .long {{.*}}Lxray_sled_0
+; CHECK:       .long {{.*}}Lxray_sled_1