A frame pointer must be used if stack pointer is modified after the
prologue. LLVM will emit pushf/popf if we need to save/restore the
FLAGS register, requiring us to have a frame pointer for the function.
There is a small twist: this sequence might exist in user code via
inline-assembly. For now, conservatively assume that such functions
require a frame pointer. For real world justification, please see
clang's implementation of __readeflags.
This fixes PR25945.
llvm-svn: 256456
Summary: This patch changes gc.statepoint intrinsic's return type to token type instead of i32 type. Using token types could prevent LLVM to merge different gc.statepoint nodes into PHI nodes and cause further problems with gc relocations. The patch also changes the way on how gc.relocate and gc.result look for their corresponding gc.statepoint on unwind path. The current implementation uses the selector value extracted from a { i8*, i32 } landingpad as a hook to find the gc.statepoint, while the patch directly uses a token type landingpad (http://reviews.llvm.org/D15405) to find the gc.statepoint.
Reviewers: sanjoy, JosephTremoulet, pgavlin, igor-laevsky, mjacob
Subscribers: reames, mjacob, sanjoy, llvm-commits
Differential Revision: http://reviews.llvm.org/D15662
llvm-svn: 256443
The linker has to create __tls_get_addr, end and _end symbols.
Previously, these symbols were created in createSections().
But they are not actually related to creating output sections.
This patch moves code out of the function.
llvm-svn: 256441
Previously, this code was directly written in createSections()
function. This patch moves some code out of that function to a
new class.
llvm-svn: 256438
The number of output sections is usually limited, so the cost
of allocating them is not a bottleneck. This patch simplifies
the code by removing the allocators.
llvm-svn: 256437
OutputSectionBase already has virtual member functions.
This patch makes addSection() a virtual function to remove code
from Writer::createSections().
llvm-svn: 256436
The R_MIPS_GPREL16 / R_MIPS_GPREL32 relocations use the following
expressions for calculations:
```
local symbol: S + A + GP0 - GP
global symbol: S + A - GP
GP - Represents the final gp value, i.e. _gp symbol
GP0 - Represents the gp value used to create the relocatable object
```
The GP0 value is taken from the .reginfo data section defined by an object
file. To implement that I keep a reference to `MipsReginfoInputSection`
in the `ObjectFile` class. This reference is used by the
`ObjectFile::getMipsGp0` method to return the GP0 value.
Differential Revision: http://reviews.llvm.org/D15760
llvm-svn: 256416
The file crtbeginT.o has relocations pointing to the start of an empty
.eh_frame that is known to be the first in the link. It does that to
identify the start of the output .eh_frame. Handle this special case.
Differential revision: http://reviews.llvm.org/D15610
llvm-svn: 256414
We already know how to properly print out basic blocks in
printAsOperand, we should not roll it ourselves in
AsmPrinter::EmitBasicBlockStart. No functionality change is intended.
llvm-svn: 256413
This function was longer than 250 lines, which is way too long
in my own standard. This patch reduces the size. It is still
too long, but this patch should be toward the right direction.
llvm-svn: 256411
David Majnemer