From 57ac1f458a754f30cf500410b438fb260f9b8fe5 Mon Sep 17 00:00:00 2001 From: Bill Schmidt Date: Tue, 11 Dec 2012 20:30:11 +0000 Subject: This patch implements the general dynamic TLS model for 64-bit PowerPC. Given a thread-local symbol x with global-dynamic access, the generated code to obtain x's address is: Instruction Relocation Symbol addis ra,r2,x@got@tlsgd@ha R_PPC64_GOT_TLSGD16_HA x addi r3,ra,x@got@tlsgd@l R_PPC64_GOT_TLSGD16_L x bl __tls_get_addr(x@tlsgd) R_PPC64_TLSGD x R_PPC64_REL24 __tls_get_addr nop The implementation borrows from the medium code model work for introducing special forms of ADDIS and ADDI into the DAG representation. This is made slightly more complicated by having to introduce a call to the external function __tls_get_addr. Using the full call machinery is overkill and, more importantly, makes it difficult to add a special relocation. So I've introduced another opcode GET_TLS_ADDR to represent the function call, and surrounded it with register copies to set up the parameter and return value. Most of the code is pretty straightforward. I ran into one peculiarity when I introduced a new PPC opcode BL8_NOP_ELF_TLSGD, which is just like BL8_NOP_ELF except that it takes another parameter to represent the symbol ("x" above) that requires a relocation on the call. Something in the TblGen machinery causes BL8_NOP_ELF and BL8_NOP_ELF_TLSGD to be treated identically during the emit phase, so this second operand was never visited to generate relocations. This is the reason for the slightly messy workaround in PPCMCCodeEmitter.cpp:getDirectBrEncoding(). Two new tests are included to demonstrate correct external assembly and correct generation of relocations using the integrated assembler. Comments welcome! Thanks, Bill git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169910 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp') diff --git a/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp b/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp index 631f749581..ed7b92c19f 100644 --- a/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp +++ b/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp @@ -32,6 +32,7 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) { case FK_Data_8: case PPC::fixup_ppc_toc: case PPC::fixup_ppc_tlsreg: + case PPC::fixup_ppc_tlsgd: return Value; case PPC::fixup_ppc_lo14: case PPC::fixup_ppc_toc16_ds: @@ -85,7 +86,8 @@ public: { "fixup_ppc_toc", 0, 64, 0 }, { "fixup_ppc_toc16", 16, 16, 0 }, { "fixup_ppc_toc16_ds", 16, 14, 0 }, - { "fixup_ppc_tlsreg", 0, 0, 0 } + { "fixup_ppc_tlsreg", 0, 0, 0 }, + { "fixup_ppc_tlsgd", 0, 0, 0 } }; if (Kind < FirstTargetFixupKind) -- cgit v1.2.3-18-g5258