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llvm-mirror/test/CodeGen/ARM/xray-tail-call-sled.ll

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[XRay] Support for for tail calls for ARM no-Thumb This patch adds simplified support for tail calls on ARM with XRay instrumentation. Known issue: compiled with generic flags: `-O3 -g -fxray-instrument -Wall -std=c++14 -ffunction-sections -fdata-sections` (this list doesn't include my specific flags like --target=armv7-linux-gnueabihf etc.), the following program #include <cstdio> #include <cassert> #include <xray/xray_interface.h> [[clang::xray_always_instrument]] void __attribute__ ((noinline)) fC() { std::printf("In fC()\n"); } [[clang::xray_always_instrument]] void __attribute__ ((noinline)) fB() { std::printf("In fB()\n"); fC(); } [[clang::xray_always_instrument]] void __attribute__ ((noinline)) fA() { std::printf("In fA()\n"); fB(); } // Avoid infinite recursion in case the logging function is instrumented (so calls logging // function again). [[clang::xray_never_instrument]] void simplyPrint(int32_t functionId, XRayEntryType xret) { printf("XRay: functionId=%d type=%d.\n", int(functionId), int(xret)); } int main(int argc, char* argv[]) { __xray_set_handler(simplyPrint); printf("Patching...\n"); __xray_patch(); fA(); printf("Unpatching...\n"); __xray_unpatch(); fA(); return 0; } gives the following output: Patching... XRay: functionId=3 type=0. In fA() XRay: functionId=3 type=1. XRay: functionId=2 type=0. In fB() XRay: functionId=2 type=1. XRay: functionId=1 type=0. XRay: functionId=1 type=1. In fC() Unpatching... In fA() In fB() In fC() So for function fC() the exit sled seems to be called too much before function exit: before printing In fC(). Debugging shows that the above happens because printf from fC is also called as a tail call. So first the exit sled of fC is executed, and only then printf is jumped into. So it seems we can't do anything about this with the current approach (i.e. within the simplification described in https://reviews.llvm.org/D23988 ). Differential Revision: https://reviews.llvm.org/D25030 llvm-svn: 284456
2016-10-18 07:54:15 +02:00
; RUN: llc -filetype=asm -o - -mtriple=armv7-unknown-linux-gnu < %s | FileCheck %s
[xray] Add XRay support for Mach-O in CodeGen Currently, XRay only supports emitting the XRay table (xray_instr_map) on ELF binaries. Let's add Mach-O support. Differential Revision: https://reviews.llvm.org/D26983 llvm-svn: 287734
2016-11-23 03:07:04 +01:00
; RUN: llc -filetype=asm -o - -mtriple=armv7-apple-ios6.0.0 < %s | FileCheck %s
[XRay] Support for for tail calls for ARM no-Thumb This patch adds simplified support for tail calls on ARM with XRay instrumentation. Known issue: compiled with generic flags: `-O3 -g -fxray-instrument -Wall -std=c++14 -ffunction-sections -fdata-sections` (this list doesn't include my specific flags like --target=armv7-linux-gnueabihf etc.), the following program #include <cstdio> #include <cassert> #include <xray/xray_interface.h> [[clang::xray_always_instrument]] void __attribute__ ((noinline)) fC() { std::printf("In fC()\n"); } [[clang::xray_always_instrument]] void __attribute__ ((noinline)) fB() { std::printf("In fB()\n"); fC(); } [[clang::xray_always_instrument]] void __attribute__ ((noinline)) fA() { std::printf("In fA()\n"); fB(); } // Avoid infinite recursion in case the logging function is instrumented (so calls logging // function again). [[clang::xray_never_instrument]] void simplyPrint(int32_t functionId, XRayEntryType xret) { printf("XRay: functionId=%d type=%d.\n", int(functionId), int(xret)); } int main(int argc, char* argv[]) { __xray_set_handler(simplyPrint); printf("Patching...\n"); __xray_patch(); fA(); printf("Unpatching...\n"); __xray_unpatch(); fA(); return 0; } gives the following output: Patching... XRay: functionId=3 type=0. In fA() XRay: functionId=3 type=1. XRay: functionId=2 type=0. In fB() XRay: functionId=2 type=1. XRay: functionId=1 type=0. XRay: functionId=1 type=1. In fC() Unpatching... In fA() In fB() In fC() So for function fC() the exit sled seems to be called too much before function exit: before printing In fC(). Debugging shows that the above happens because printf from fC is also called as a tail call. So first the exit sled of fC is executed, and only then printf is jumped into. So it seems we can't do anything about this with the current approach (i.e. within the simplification described in https://reviews.llvm.org/D23988 ). Differential Revision: https://reviews.llvm.org/D25030 llvm-svn: 284456
2016-10-18 07:54:15 +02:00
define i32 @callee() nounwind noinline uwtable "function-instrument"="xray-always" {
; CHECK: .p2align 2
; CHECK-LABEL: Lxray_sled_0:
; CHECK-NEXT: b #20
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-LABEL: Ltmp0:
ret i32 0
; CHECK-NEXT: mov r0, #0
; CHECK-NEXT: .p2align 2
; CHECK-LABEL: Lxray_sled_1:
; CHECK-NEXT: b #20
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-LABEL: Ltmp1:
; CHECK-NEXT: bx lr
}
define i32 @caller() nounwind noinline uwtable "function-instrument"="xray-always" {
; CHECK: .p2align 2
; CHECK-LABEL: Lxray_sled_2:
; CHECK-NEXT: b #20
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-LABEL: Ltmp2:
; CHECK: .p2align 2
; CHECK-LABEL: Lxray_sled_3:
; CHECK-NEXT: b #20
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-LABEL: Ltmp3:
%retval = tail call i32 @callee()
[xray] Add XRay support for Mach-O in CodeGen Currently, XRay only supports emitting the XRay table (xray_instr_map) on ELF binaries. Let's add Mach-O support. Differential Revision: https://reviews.llvm.org/D26983 llvm-svn: 287734
2016-11-23 03:07:04 +01:00
; CHECK: b {{.*}}callee
[XRay] Support for for tail calls for ARM no-Thumb This patch adds simplified support for tail calls on ARM with XRay instrumentation. Known issue: compiled with generic flags: `-O3 -g -fxray-instrument -Wall -std=c++14 -ffunction-sections -fdata-sections` (this list doesn't include my specific flags like --target=armv7-linux-gnueabihf etc.), the following program #include <cstdio> #include <cassert> #include <xray/xray_interface.h> [[clang::xray_always_instrument]] void __attribute__ ((noinline)) fC() { std::printf("In fC()\n"); } [[clang::xray_always_instrument]] void __attribute__ ((noinline)) fB() { std::printf("In fB()\n"); fC(); } [[clang::xray_always_instrument]] void __attribute__ ((noinline)) fA() { std::printf("In fA()\n"); fB(); } // Avoid infinite recursion in case the logging function is instrumented (so calls logging // function again). [[clang::xray_never_instrument]] void simplyPrint(int32_t functionId, XRayEntryType xret) { printf("XRay: functionId=%d type=%d.\n", int(functionId), int(xret)); } int main(int argc, char* argv[]) { __xray_set_handler(simplyPrint); printf("Patching...\n"); __xray_patch(); fA(); printf("Unpatching...\n"); __xray_unpatch(); fA(); return 0; } gives the following output: Patching... XRay: functionId=3 type=0. In fA() XRay: functionId=3 type=1. XRay: functionId=2 type=0. In fB() XRay: functionId=2 type=1. XRay: functionId=1 type=0. XRay: functionId=1 type=1. In fC() Unpatching... In fA() In fB() In fC() So for function fC() the exit sled seems to be called too much before function exit: before printing In fC(). Debugging shows that the above happens because printf from fC is also called as a tail call. So first the exit sled of fC is executed, and only then printf is jumped into. So it seems we can't do anything about this with the current approach (i.e. within the simplification described in https://reviews.llvm.org/D23988 ). Differential Revision: https://reviews.llvm.org/D25030 llvm-svn: 284456
2016-10-18 07:54:15 +02:00
ret i32 %retval
}
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