[xray] Honor xray-never function-instrument attribute

function-instrument=xray-never wasn't actually honored before. We were
getting lucky that it worked because CodeGenFunction would omit the
other xray attributes when a function was annotated with
xray_never_instrument. This patch adds proper support.

Differential Revision: https://reviews.llvm.org/D89441

diff --git a/llvm/lib/CodeGen/XRayInstrumentation.cpp b/llvm/lib/CodeGen/XRayInstrumentation.cpp
index d60db38..11d1b30 100644 (file)
--- a/llvm/lib/CodeGen/XRayInstrumentation.cpp
+++ b/llvm/lib/CodeGen/XRayInstrumentation.cpp
@@ -147,6 +147,10 @@ bool XRayInstrumentation::runOnMachineFunction(MachineFunction &MF) {
   auto InstrAttr = F.getFnAttribute("function-instrument");
   bool AlwaysInstrument = InstrAttr.isStringAttribute() &&
                           InstrAttr.getValueAsString() == "xray-always";
+  bool NeverInstrument = InstrAttr.isStringAttribute() &&
+                         InstrAttr.getValueAsString() == "xray-never";
+  if (NeverInstrument && !AlwaysInstrument)
+    return false;
   auto ThresholdAttr = F.getFnAttribute("xray-instruction-threshold");
   auto IgnoreLoopsAttr = F.getFnAttribute("xray-ignore-loops");
   unsigned int XRayThreshold = 0;

diff --git a/llvm/test/CodeGen/AArch64/xray-attribute-instrumentation.ll b/llvm/test/CodeGen/AArch64/xray-attribute-instrumentation.ll
index 6511304..b14463e 100644 (file)
--- a/llvm/test/CodeGen/AArch64/xray-attribute-instrumentation.ll
+++ b/llvm/test/CodeGen/AArch64/xray-attribute-instrumentation.ll
@@ -1,6 +1,7 @@
 ; RUN: llc -filetype=asm -o - -mtriple=aarch64-unknown-linux-gnu < %s | FileCheck %s
 
 define i32 @foo() nounwind noinline uwtable "function-instrument"="xray-always" {
+; CHECK-LABEL: foo:
 ; CHECK-LABEL: Lxray_sled_0:
 ; CHECK-NEXT:  b  #32
 ; CHECK-NEXT:  nop
@@ -24,8 +25,80 @@ define i32 @foo() nounwind noinline uwtable "function-instrument"="xray-always"
 ; CHECK-LABEL: Ltmp1:
 ; CHECK-NEXT:  ret
 }
+
 ; CHECK-LABEL: xray_instr_map
 ; CHECK-LABEL: Lxray_sleds_start0
 ; CHECK:       .xword .Lxray_sled_0
 ; CHECK:       .xword .Lxray_sled_1
 ; CHECK-LABEL: Lxray_sleds_end0
+
+define i32 @bar() nounwind noinline uwtable "function-instrument"="xray-never" "function-instrument"="xray-always" {
+; CHECK-LABEL: bar:
+; CHECK-LABEL: Lxray_sled_2:
+; CHECK-NEXT:  b  #32
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-LABEL: Ltmp4:
+  ret i32 0
+; CHECK-LABEL: Lxray_sled_3:
+; CHECK-NEXT:  b  #32
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-LABEL: Ltmp5:
+; CHECK-NEXT:  ret
+}
+
+; CHECK-LABEL: xray_instr_map
+; CHECK-LABEL: Lxray_sleds_start1
+; CHECK:       .xword .Lxray_sled_2
+; CHECK:       .xword .Lxray_sled_3
+; CHECK-LABEL: Lxray_sleds_end1
+
+define i32 @instrumented() nounwind noinline uwtable "xray-instruction-threshold"="1" {
+; CHECK-LABEL: instrumented:
+; CHECK-LABEL: Lxray_sled_4:
+; CHECK-NEXT:  b  #32
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-LABEL: Ltmp8:
+  ret i32 0
+; CHECK-LABEL: Lxray_sled_5:
+; CHECK-NEXT:  b  #32
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-NEXT:  nop
+; CHECK-LABEL: Ltmp9:
+; CHECK-NEXT:  ret
+}
+
+; CHECK-LABEL: xray_instr_map
+; CHECK-LABEL: Lxray_sleds_start2
+; CHECK:       .xword .Lxray_sled_4
+; CHECK:       .xword .Lxray_sled_5
+; CHECK-LABEL: Lxray_sleds_end2
+
+define i32 @not_instrumented() nounwind noinline uwtable "xray-instruction-threshold"="1" "function-instrument"="xray-never" {
+; CHECK-LABEL: not_instrumented
+; CHECK-NOT: .Lxray_sled_6
+  ret i32 0
+; CHECK:  ret
+}