Merging r352246:

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r352246 | mtrofin | 2019-01-25 22:49:54 +0100 (Fri, 25 Jan 2019) | 23 lines

[llvm] Opt-in flag for X86DiscriminateMemOps

Summary:
Currently, if an instruction with a memory operand has no debug information,
X86DiscriminateMemOps will generate one based on the first line of the
enclosing function, or the last seen debug info.

This may cause confusion in certain debugging scenarios. The long term
approach would be to use the line number '0' in such cases, however, that
brings in challenges: the base discriminator value range is limited
(4096 values).

For the short term, adding an opt-in flag for this feature.

See bug 40319 (https://bugs.llvm.org/show_bug.cgi?id=40319)

Reviewers: dblaikie, jmorse, gbedwell

Reviewed By: dblaikie

Subscribers: aprantl, eraman, hiraditya

Differential Revision: https://reviews.llvm.org/D57257
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_80@352867 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86DiscriminateMemOps.cpp b/lib/Target/X86/X86DiscriminateMemOps.cpp
index 3654bf04f4e988547f3b507ea90607a5b06f3ee7..6bee20b617dde91b346402b4aaca3938114f48fe 100644 (file)
--- a/lib/Target/X86/X86DiscriminateMemOps.cpp
+++ b/lib/Target/X86/X86DiscriminateMemOps.cpp
@@ -27,6 +27,14 @@ using namespace llvm;
 
 #define DEBUG_TYPE "x86-discriminate-memops"
 
+static cl::opt<bool> EnableDiscriminateMemops(
+    DEBUG_TYPE, cl::init(false),
+    cl::desc("Generate unique debug info for each instruction with a memory "
+             "operand. Should be enabled for profile-drived cache prefetching, "
+             "both in the build of the binary being profiled, as well as in "
+             "the build of the binary consuming the profile."),
+    cl::Hidden);
+
 namespace {
 
 using Location = std::pair<StringRef, unsigned>;
@@ -67,6 +75,9 @@ char X86DiscriminateMemOps::ID = 0;
 X86DiscriminateMemOps::X86DiscriminateMemOps() : MachineFunctionPass(ID) {}
 
 bool X86DiscriminateMemOps::runOnMachineFunction(MachineFunction &MF) {
+  if (!EnableDiscriminateMemops)
+    return false;
+
   DISubprogram *FDI = MF.getFunction().getSubprogram();
   if (!FDI || !FDI->getUnit()->getDebugInfoForProfiling())
     return false;

diff --git a/lib/Target/X86/X86InsertPrefetch.cpp b/lib/Target/X86/X86InsertPrefetch.cpp
index 30b46a09ef0f90131127c47f366eb09ce8ce4530..8bd57aa2278bad7c14aea64c7b75696cd1e6677f 100644 (file)
--- a/lib/Target/X86/X86InsertPrefetch.cpp
+++ b/lib/Target/X86/X86InsertPrefetch.cpp
@@ -34,7 +34,8 @@ using namespace sampleprof;
 
 static cl::opt<std::string>
     PrefetchHintsFile("prefetch-hints-file",
-                      cl::desc("Path to the prefetch hints profile."),
+                      cl::desc("Path to the prefetch hints profile. See also "
+                               "-x86-discriminate-memops"),
                       cl::Hidden);
 namespace {
 

diff --git a/test/CodeGen/X86/discriminate-mem-ops.ll b/test/CodeGen/X86/discriminate-mem-ops.ll
index b77a91fafd2cd8681ed64d8882f4b4544f77f209..a30dc22a0d9c02dc26193303142e169bd8e57361 100644 (file)
--- a/test/CodeGen/X86/discriminate-mem-ops.ll
+++ b/test/CodeGen/X86/discriminate-mem-ops.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s | FileCheck %s
+; RUN: llc -x86-discriminate-memops  < %s | FileCheck %s
 ;
 ; original source, compiled with -O3 -gmlt -fdebug-info-for-profiling:
 ; int sum(int* arr, int pos1, int pos2) {

diff --git a/test/CodeGen/X86/insert-prefetch-inline.ll b/test/CodeGen/X86/insert-prefetch-inline.ll
index 5f8373f9480c9624f0d0222b301bd8c1ada51ebe..62c02fa33291d2d592a624ea08d6a99af0d5e425 100644 (file)
--- a/test/CodeGen/X86/insert-prefetch-inline.ll
+++ b/test/CodeGen/X86/insert-prefetch-inline.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -prefetch-hints-file=%S/insert-prefetch-inline.afdo | FileCheck %s
+; RUN: llc < %s -x86-discriminate-memops -prefetch-hints-file=%S/insert-prefetch-inline.afdo | FileCheck %s
 ;
 ; Verify we can insert prefetch instructions in code belonging to inlined
 ; functions.

diff --git a/test/CodeGen/X86/insert-prefetch-invalid-instr.ll b/test/CodeGen/X86/insert-prefetch-invalid-instr.ll
index 004fb56a56eb8a289705cc1ff2911b3f22e0617d..d0c4ac378b63b285558d8c507b1448aa18a60c97 100644 (file)
--- a/test/CodeGen/X86/insert-prefetch-invalid-instr.ll
+++ b/test/CodeGen/X86/insert-prefetch-invalid-instr.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -prefetch-hints-file=%S/insert-prefetch-invalid-instr.afdo | FileCheck %s
+; RUN: llc < %s -x86-discriminate-memops -prefetch-hints-file=%S/insert-prefetch-invalid-instr.afdo | FileCheck %s
 ; ModuleID = 'prefetch.cc'
 source_filename = "prefetch.cc"
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"

diff --git a/test/CodeGen/X86/insert-prefetch.ll b/test/CodeGen/X86/insert-prefetch.ll
index 9e77772df7746b96c42aefa3172da73d54fc986d..fe0fd9877f193ee047a37a68fa3a0ae5f5b8f960 100644 (file)
--- a/test/CodeGen/X86/insert-prefetch.ll
+++ b/test/CodeGen/X86/insert-prefetch.ll
@@ -1,5 +1,5 @@
-; RUN: llc < %s -prefetch-hints-file=%S/insert-prefetch.afdo | FileCheck %s
-; RUN: llc < %s -prefetch-hints-file=%S/insert-prefetch-other.afdo | FileCheck %s -check-prefix=OTHERS
+; RUN: llc < %s -x86-discriminate-memops -prefetch-hints-file=%S/insert-prefetch.afdo | FileCheck %s
+; RUN: llc < %s -x86-discriminate-memops -prefetch-hints-file=%S/insert-prefetch-other.afdo | FileCheck %s -check-prefix=OTHERS
 ;
 ; original source, compiled with -O3 -gmlt -fdebug-info-for-profiling:
 ; int sum(int* arr, int pos1, int pos2) {