patch-r263312-llvm-r196986-allow-realign-alloca.diff revision 269012
1Pull in r196986 from upstream llvm trunk (by Reid Kleckner): 2 3 Revert the backend fatal error from r196939 4 5 The combination of inline asm, stack realignment, and dynamic allocas 6 turns out to be too common to reject out of hand. 7 8 ASan inserts empy inline asm fragments and uses aligned allocas. 9 Compiling any trivial function containing a dynamic alloca with ASan is 10 enough to trigger the check. 11 12 XFAIL the test cases that would be miscompiled and add one that uses the 13 relevant functionality. 14 15Introduced here: http://svnweb.freebsd.org/changeset/base/263312 16 17Index: lib/Target/X86/X86RegisterInfo.cpp 18=================================================================== 19--- lib/Target/X86/X86RegisterInfo.cpp 20+++ lib/Target/X86/X86RegisterInfo.cpp 21@@ -347,12 +347,6 @@ BitVector X86RegisterInfo::getReservedRegs(const M 22 "Stack realignment in presence of dynamic allocas is not supported with" 23 "this calling convention."); 24 25- // FIXME: Do a proper analysis of the inline asm to see if it actually 26- // conflicts with the base register we chose. 27- if (MF.hasInlineAsm()) 28- report_fatal_error("Stack realignment in presence of dynamic stack " 29- "adjustments is not supported with inline assembly."); 30- 31 for (MCSubRegIterator I(getBaseRegister(), this, /*IncludeSelf=*/true); 32 I.isValid(); ++I) 33 Reserved.set(*I); 34Index: test/CodeGen/X86/inline-asm-stack-realign3.ll 35=================================================================== 36--- test/CodeGen/X86/inline-asm-stack-realign3.ll 37+++ test/CodeGen/X86/inline-asm-stack-realign3.ll 38@@ -0,0 +1,29 @@ 39+; RUN: llc -march=x86 < %s | FileCheck %s 40+ 41+declare void @bar(i32* %junk) 42+ 43+define i32 @foo(i1 %cond) { 44+entry: 45+ %r = alloca i32, align 128 46+ store i32 -1, i32* %r, align 128 47+ br i1 %cond, label %doit, label %skip 48+ 49+doit: 50+ call void asm sideeffect "xor %ecx, %ecx\0A\09mov %ecx, $0", "=*m,~{ecx},~{flags}"(i32* %r) 51+ %junk = alloca i32 52+ call void @bar(i32* %junk) 53+ br label %skip 54+ 55+skip: 56+ %0 = load i32* %r, align 128 57+ ret i32 %0 58+} 59+ 60+; CHECK-LABEL: foo: 61+; CHECK: pushl %ebp 62+; CHECK: andl $-128, %esp 63+; CHECK: xor %ecx, %ecx 64+; CHECK-NEXT: mov %ecx, (%esi) 65+; CHECK: movl (%esi), %eax 66+; CHECK: popl %ebp 67+; CHECK: ret 68Index: test/CodeGen/X86/inline-asm-stack-realign.ll 69=================================================================== 70--- test/CodeGen/X86/inline-asm-stack-realign.ll 71+++ test/CodeGen/X86/inline-asm-stack-realign.ll 72@@ -1,8 +1,8 @@ 73 ; RUN: not llc -mtriple=i686-pc-win32 < %s 2>&1 | FileCheck %s 74 75-; We don't currently support realigning the stack and adjusting the stack 76-; pointer in inline asm. This commonly happens in MS inline assembly using 77-; push and pop. 78+; FIXME: This is miscompiled due to our unconditional use of ESI as the base 79+; pointer. 80+; XFAIL: 81 82 ; CHECK: Stack realignment in presence of dynamic stack adjustments is not supported with inline assembly 83 84Index: test/CodeGen/X86/inline-asm-stack-realign2.ll 85=================================================================== 86--- test/CodeGen/X86/inline-asm-stack-realign2.ll 87+++ test/CodeGen/X86/inline-asm-stack-realign2.ll 88@@ -1,7 +1,8 @@ 89 ; RUN: not llc -mtriple=i686-pc-win32 < %s 2>&1 | FileCheck %s 90 91-; We don't currently support realigning the stack and adjusting the stack 92-; pointer in inline asm. This can even happen in GNU asm. 93+; FIXME: This is miscompiled due to our unconditional use of ESI as the base 94+; pointer. 95+; XFAIL: 96 97 ; CHECK: Stack realignment in presence of dynamic stack adjustments is not supported with inline assembly 98 99