search for: eflags

...----------------------------- 1 file changed, 47 insertions(+), 73 deletions(-) diff --git a/src/connections.c b/src/connections.c index 8dc1925..f9edea7 100644 --- a/src/connections.c +++ b/src/connections.c @@ -237,13 +237,57 @@ free_connection (struct connection *conn) } static int +compute_eflags (struct connection *conn, uint16_t *flags) +{ + uint16_t eflags = NBD_FLAG_HAS_FLAGS; + int fl; + + fl = plugin_can_write (conn); + if (fl == -1) + return -1; + if (readonly || !fl) { + eflags |= NBD_FLAG_READ_ONLY; + conn->readonly = 1; + } + if (!conn->readonly) { + eflag...

...f1c1c..07b6c9e 100644 --- a/generator/states-newstyle-opt-export-name.c +++ b/generator/states-newstyle-opt-export-name.c @@ -58,13 +58,13 @@ return 0; NEWSTYLE.OPT_EXPORT_NAME.CHECK_REPLY: - conn->h->exportsize = be64toh (conn->sbuf.export_name_reply.exportsize); - conn->h->eflags = be16toh (conn->sbuf.export_name_reply.eflags); - debug (conn->h, "exportsize: %" PRIu64 " eflags: 0x%" PRIx16, - conn->h->exportsize, conn->h->eflags); - if (conn->h->eflags == 0) { + uint64_t exportsize; + uint16_t eflags; + + exportsize =...

On Jun 3, 2011, at 2:59 AM, Galanov, Sergey wrote: > Hi, Bill and Jakob. > > I don't quite understand. I am talking about CMOV_GR* instructions which are conservatively marked as clobbering EFLAGS in X86InstrCompiler.td. Doesn't that mean there cannot be any use of EFLAGS in subsequent instructions before it is defined by some other instruction? > > I also don't understand the remark about resetting EFLAGS. What kind of reset is meant? In case of normal branch instructions the...

Well, the point is CMOV_GR* are marked clobbering EFLAGS conservatively just in case they turn out to be lowered into a sequence containing XOR %reg,%reg which indeed clobbers EFLAGS. This means there might not be any instruction which actually uses this EFLAGS value. For an example we can look no further than the actual test which has been disabled aft...

Thanks for spelling it out, now I understand. On Jun 5, 2011, at 6:11 AM, Galanov, Sergey wrote: > Well, the point is CMOV_GR* are marked clobbering EFLAGS conservatively just in case they turn out to be lowered into a sequence containing XOR %reg,%reg which indeed clobbers EFLAGS. This means there might not be any instruction which actually uses this EFLAGS value. This actually looks like a leftover from some older code. EmitLoweredSelect() will nev...

Using Clang/LLVM 3.6.0 we are observing a case where the optimizations are clobbering EFLAGS on x86_64. This is inconvenient when the status of bit 9 (IF), which controls interrupts, changes. Here's a simple test program. Assume that the external function foo() modifies the IF bit in EFLAGS. --- #include <stdlib.h> #include <stdbool.h> void foo(void); int a; int ba...

Per recent discussion here: https://www.redhat.com/archives/libguestfs/2019-May/thread.html#00175

Hello, Here is one question regarding the LLVM TableGen: Which file in the llvm/lib/Target/X86 folder describes how the bits in the EFLAGS register are modified by the x86 instructions? For example, in the "X86InstrInfo.td" file, lines 2134-2135, it says: let SchedRW = [WriteALU], Defs = [EFLAGS], Uses = [EFLAGS] in { def CLC : I<0xF8, RawFrm, (outs), (ins), "clc", []>; So it says the Defs of CLC is EFLAGS...

...mit pushf / popf. I'm not sure this patch to fix it ever got committed: http://reviews.llvm.org/D6629 On Wed, Jul 29, 2015 at 3:11 PM, Michael Hordijk <hoffbrinkle at hotmail.com> wrote: > > Using Clang/LLVM 3.6.0 we are observing a case where the optimizations are > clobbering EFLAGS on x86_64. This is inconvenient when the status of bit 9 > (IF), which controls interrupts, changes. > > Here's a simple test program. Assume that the external function foo() > modifies the IF bit in EFLAGS. > > --- > > #include <stdlib.h> > #include <stdbo...

--- tests/Makefile.am | 3 + tests/test-eflags.sh | 222 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 225 insertions(+) diff --git a/tests/Makefile.am b/tests/Makefile.am index a01c47c..173d622 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -282,6 +282,9 @@ test_oldstyle_LDADD = libtest.la $(LIBGUESTFS_LIBS) endif...

...hysreg-defining instruction (like CMP or TEST) is allowed to be shared in several instructions unless that register is not clobbered (and this is what we have with CMOV_FR64). Wouldn't it be safe then to not set the live-in flag in EmitLoweredSelect for instructions which are marked as defining EFLAGS (like the integer pseudo cmovs)? >> > Hi Sergey, > > I'm not certain what that would buy us. If I understand your suggestion correctly, not setting the EFLAGS as live-in to a basic block would mean that we'd have to execute the instruction to reset the EFLAGS register, righ...

Hi, Bill and Jakob. I don't quite understand. I am talking about CMOV_GR* instructions which are conservatively marked as clobbering EFLAGS in X86InstrCompiler.td. Doesn't that mean there cannot be any use of EFLAGS in subsequent instructions before it is defined by some other instruction? I also don't understand the remark about resetting EFLAGS. What kind of reset is meant? In case of normal branch instructions there is no s...

...old-style connection diff -r d7d5078d08c7 -r dbd1ea0a401c src/connections.c --- a/src/connections.c Sun Sep 25 05:04:02 2016 +0200 +++ b/src/connections.c Mon Sep 26 17:28:54 2016 +0200 @@ -155,7 +155,7 @@ struct old_handshake handshake; int64_t r; uint64_t exportsize; - uint16_t gflags, eflags; + uint32_t flags; int fl; r = plugin_get_size (conn); @@ -169,14 +169,13 @@ exportsize = (uint64_t) r; conn->exportsize = exportsize; - gflags = 0; - eflags = NBD_FLAG_HAS_FLAGS; + flags = NBD_FLAG_HAS_FLAGS; fl = plugin_can_write (conn); if (fl == -1) return -1...

Using Clang/LLVM 3.6.0 we are observing a case where the optimizations are clobbering EFLAGS on x86_64. This is inconvenient when the status of bit 9 (IF), which controls interrupts, changes. Here's a simple test program. Assume that the external function foo() modifies the IF bit in EFLAGS. #include <stdlib.h> #include <stdbool.h> void foo(void); int a; int bar(voi...

...+ common/protocol/protocol.h | 2 ++ server/internal.h | 4 +++ server/filters.c | 33 ++++++++++++++++++++++- server/plugins.c | 34 ++++++++++++++++++++++++ server/protocol-handshake.c | 10 ++++++- server/protocol.c | 25 +++++++++++++++++ tests/test-eflags.sh | 53 ++++++++++++++++++++----------------- 8 files changed, 144 insertions(+), 27 deletions(-) diff --git a/docs/nbdkit-protocol.pod b/docs/nbdkit-protocol.pod index f706cfd..6b85c14 100644 --- a/docs/nbdkit-protocol.pod +++ b/docs/nbdkit-protocol.pod @@ -152,6 +152,16 @@ when structure...

...n the internal Apple bugtracker I believe and so not available to the general public :)) Some discussion can be found here: http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20100531/102160.html. Unfortunately, no real testcase is provided, just abstract scenario description. Basically a EFLAGS-clobbering instruction is not sunk if EFLAGS might be live out of the current block and since a conditional branch doesn't mark its EFLAGS use as a kill, that effectively means it is never sunk. But how can that happen? I think the only way for it is when EFLAGS def and use are located in diffe...

...hysreg-defining instruction (like CMP or TEST) is allowed to be shared in several instructions unless that register is not clobbered (and this is what we have with CMOV_FR64). Wouldn't it be safe then to not set the live-in flag in EmitLoweredSelect for instructions which are marked as defining EFLAGS (like the integer pseudo cmovs)? Thanks, Sergey -----Original Message----- From: Bill Wendling [mailto:wendling at apple.com] Sent: Thursday, June 02, 2011 12:00 AM To: Galanov, Sergey Cc: llvmdev at cs.uiuc.edu Subject: Re: [LLVMdev] MachineSink and EFLAGS On Jun 1, 2011, at 9:18 AM, Galanov,...

Hello llvm-dev list, i am implementing an X86 Machine Pass that at some point needs to push/pop eflags on the stack. This pass is hooked at preRegAlloc and LLVM is 3.7.0. I got two big problems: 1) I didn't found a way to emit a pushfq instruction in a clean way, i.e. with BuildMI(*MBB, MI, DL, TII.get(X86::PUSHF64)). Even if both EFLAGS and RSP are added to the MBB liveins, the Machine Verifi...

...1)); newEntry->push_back(plop); return false; } And here is the resulting code (it's a simple program with some 'if'): (null) BB#4 JMP_4 <BB#0> if.end BB#3 %RDI<def> = LEA64r %RIP, 1, %noreg, <ga:@.str2>, %noreg ADJCALLSTACKDOWN64 0, %RSP<imp-def>, %EFLAGS<imp-def>, %RSP<imp-use> %AL<def> = MOV8ri 0 CALL64pcrel32 <ga:@printf>, <regmask>, %RSP<imp-use>, %AL<imp-use,kill>, %RDI<imp-use,kill>, %EAX<imp-def> ADJCALLSTACKUP64 0, 0, %RSP<imp-def>, %EFLAGS<imp-def>, %RSP<imp-use> %ECX&l...

...Apple bugtracker I believe and so not available to the general public J) > Some discussion can be found here: http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20100531/102160.html. Unfortunately, no real testcase is provided, just abstract scenario description. > > Basically a EFLAGS-clobbering instruction is not sunk if EFLAGS might be live out of the current block and since a conditional branch doesn’t mark its EFLAGS use as a kill, that effectively means it is never sunk. But how can that happen? I think the only way for it is when EFLAGS def and use are located in different...