diff options
Diffstat (limited to 'gcc/varasm.c')
| -rw-r--r-- | gcc/varasm.c | 266 |
1 files changed, 170 insertions, 96 deletions
diff --git a/gcc/varasm.c b/gcc/varasm.c index 9210c413b25..d2aeac6aabf 100644 --- a/gcc/varasm.c +++ b/gcc/varasm.c @@ -52,6 +52,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA #include "tree-mudflap.h" #include "cgraph.h" #include "cfglayout.h" +#include "basic-block.h" #ifdef XCOFF_DEBUGGING_INFO #include "xcoffout.h" /* Needed for external data @@ -95,25 +96,44 @@ int size_directive_output; tree last_assemble_variable_decl; -/* The following global variable indicates if the section label for the - "cold" section of code has been output yet to the assembler. The - label is useful when running gdb. This is part of the optimization that - partitions hot and cold basic blocks into separate sections of the .o - file. */ +/* The following global variable indicates if the first basic block + in a function belongs to the cold partition or not. */ -static bool unlikely_section_label_printed = false; +bool first_function_block_is_cold; /* The following global variable indicates the label name to be put at the start of the first cold section within each function, when - partitioning basic blocks into hot and cold sections. */ + partitioning basic blocks into hot and cold sections. Used for + debug info. */ -static char *unlikely_section_label = NULL; +char *unlikely_section_label; + +/* The following global variable indicates the label name to be put at + the start of the first hot section within each function, when + partitioning basic blocks into hot and cold sections. Used for + debug info. */ + +char *hot_section_label; + +/* The following global variable indicates the label name to be put at + the end of the last hot section within each function, when + partitioning basic blocks into hot and cold sections. Used for + debug info. */ + +char *hot_section_end_label; + +/* The following global variable indicates the label name to be put at + the end of the last cold section within each function, when + partitioning basic blocks into hot and cold sections. Used for + debug info.*/ + +char *cold_section_end_label; -/* The following global variable indicates the section name to be used - for the current cold section, when partitioning hot and cold basic +/* The following global variable indicates the seciton name to be used + for the current cold section, when partitiong hot and cold basic blocks into separate sections. */ -static char *unlikely_text_section_name = NULL; +char *unlikely_text_section_name; /* We give all constants their own alias set. Perhaps redundant with MEM_READONLY_P, but pre-dates it. */ @@ -140,6 +160,7 @@ static void globalize_decl (tree); static void maybe_assemble_visibility (tree); static int in_named_entry_eq (const void *, const void *); static hashval_t in_named_entry_hash (const void *); +static void initialize_cold_section_name (void); #ifdef BSS_SECTION_ASM_OP #ifdef ASM_OUTPUT_BSS static void asm_output_bss (FILE *, tree, const char *, @@ -156,25 +177,8 @@ static bool asm_emit_uninitialised (tree, const char*, unsigned HOST_WIDE_INT); static void mark_weak (tree); -enum in_section { no_section, in_text, in_unlikely_executed_text, in_data, - in_named -#ifdef BSS_SECTION_ASM_OP - , in_bss -#endif -#ifdef CTORS_SECTION_ASM_OP - , in_ctors -#endif -#ifdef DTORS_SECTION_ASM_OP - , in_dtors -#endif -#ifdef READONLY_DATA_SECTION_ASM_OP - , in_readonly_data -#endif -#ifdef EXTRA_SECTIONS - , EXTRA_SECTIONS -#endif -}; static GTY(()) enum in_section in_section = no_section; +enum in_section last_text_section; /* Return a nonzero value if DECL has a section attribute. */ #ifndef IN_NAMED_SECTION @@ -185,6 +189,7 @@ static GTY(()) enum in_section in_section = no_section; /* Text of section name when in_section == in_named. */ static GTY(()) const char *in_named_name; +const char *last_text_section_name; /* Hash table of flags that have been used for a particular named section. */ @@ -202,24 +207,10 @@ static GTY((param_is (struct in_named_entry))) htab_t in_named_htab; EXTRA_SECTION_FUNCTIONS #endif -/* Tell assembler to switch to text section. */ - -void -text_section (void) -{ - if (in_section != in_text) - { - in_section = in_text; - fprintf (asm_out_file, "%s\n", TEXT_SECTION_ASM_OP); - } -} - -/* Tell assembler to switch to unlikely-to-be-executed text section. */ - -void -unlikely_text_section (void) +static void +initialize_cold_section_name (void) { - const char *name; + const char* name; int len; if (! unlikely_text_section_name) @@ -235,18 +226,35 @@ unlikely_text_section (void) name = TREE_STRING_POINTER (DECL_SECTION_NAME (current_function_decl)); len = strlen (name); - unlikely_text_section_name = xmalloc ((len + 10) * sizeof (char)); - strcpy (unlikely_text_section_name, name); - strcat (unlikely_text_section_name, "_unlikely"); + unlikely_text_section_name = xmalloc (len + 10); + sprintf (unlikely_text_section_name, "%s%s", name, "_unlikely"); } else - { - len = strlen (UNLIKELY_EXECUTED_TEXT_SECTION_NAME); - unlikely_text_section_name = xmalloc (len+1 * sizeof (char)); - strcpy (unlikely_text_section_name, - UNLIKELY_EXECUTED_TEXT_SECTION_NAME); - } + unlikely_text_section_name = + xstrdup (UNLIKELY_EXECUTED_TEXT_SECTION_NAME); + } +} + +/* Tell assembler to switch to text section. */ + +void +text_section (void) +{ + if (in_section != in_text) + { + in_section = in_text; + last_text_section = in_text; + fprintf (asm_out_file, "%s\n", TEXT_SECTION_ASM_OP); } +} + +/* Tell assembler to switch to unlikely-to-be-executed text section. */ + +void +unlikely_text_section (void) +{ + if (! unlikely_text_section_name) + initialize_cold_section_name (); if ((in_section != in_unlikely_executed_text) && (in_section != in_named @@ -254,12 +262,7 @@ unlikely_text_section (void) { named_section (NULL_TREE, unlikely_text_section_name, 0); in_section = in_unlikely_executed_text; - - if (!unlikely_section_label_printed) - { - ASM_OUTPUT_LABEL (asm_out_file, unlikely_section_label); - unlikely_section_label_printed = true; - } + last_text_section = in_unlikely_executed_text; } } @@ -437,6 +440,12 @@ named_section_real (const char *name, unsigned int flags, tree decl) in_section = in_named; } } + + if (in_text_section () || in_unlikely_text_section ()) + { + last_text_section = in_section; + last_text_section_name = name; + } } /* Tell assembler to change to section NAME for DECL. @@ -565,28 +574,40 @@ asm_output_aligned_bss (FILE *file, tree decl ATTRIBUTE_UNUSED, void function_section (tree decl) { - if (decl == NULL_TREE) - text_section (); + bool unlikely = false; + + if (first_function_block_is_cold) + unlikely = true; + +#ifdef USE_SELECT_SECTION_FOR_FUNCTIONS + targetm.asm_out.select_section (decl, unlikely, DECL_ALIGN (decl)); +#else + if (decl != NULL_TREE + && DECL_SECTION_NAME (decl) != NULL_TREE) + named_section (decl, (char *) 0, 0); else - { - /* ??? Typical use of this function maybe shouldn't be looking - for unlikely blocks at all - in the event that an entire - function is going into the unlikely-execute section, that - should be reflected in its DECL_SECTION_NAME. */ - rtx insns = cfun && cfun->emit ? get_insns () : 0; - bool unlikely = insns && scan_ahead_for_unlikely_executed_note (insns); + text_section (); +#endif +} +void +current_function_section (tree decl) +{ #ifdef USE_SELECT_SECTION_FOR_FUNCTIONS - targetm.asm_out.select_section (decl, unlikely, DECL_ALIGN (decl)); + bool unlikely = (in_unlikely_text_section () + || (last_text_section == in_unlikely_executed_text)); + + targetm.asm_out.select_section (decl, unlikely, DECL_ALIGN (decl)); #else - if (unlikely) - unlikely_text_section (); - else if (DECL_SECTION_NAME (decl)) - named_section (decl, 0, 0); - else - text_section (); + if (last_text_section == in_unlikely_executed_text) + unlikely_text_section (); + else if (last_text_section == in_text) + text_section (); + else if (last_text_section == in_named) + named_section (NULL_TREE, last_text_section_name, 0); + else + function_section (decl); #endif - } } /* Switch to read-only data section associated with function DECL. */ @@ -1203,16 +1224,19 @@ void assemble_start_function (tree decl, const char *fnname) { int align; + bool hot_label_written = false; - if (unlikely_text_section_name) - free (unlikely_text_section_name); - - unlikely_section_label_printed = false; unlikely_text_section_name = NULL; + first_function_block_is_cold = false; + hot_section_label = reconcat (hot_section_label, fnname, ".hot_section", NULL); unlikely_section_label = reconcat (unlikely_section_label, fnname, ".unlikely_section", NULL); - + hot_section_end_label = reconcat (hot_section_end_label, + fnname, ".end", NULL); + cold_section_end_label = reconcat (cold_section_end_label, + fnname, ".end.cold", NULL); + /* The following code does not need preprocessing in the assembler. */ app_disable (); @@ -1220,22 +1244,67 @@ assemble_start_function (tree decl, const char *fnname) if (CONSTANT_POOL_BEFORE_FUNCTION) output_constant_pool (fnname, decl); - /* Make sure the cold text (code) section is properly aligned. This - is necessary here in the case where the function has both hot and - cold sections, because we don't want to re-set the alignment when the - section switch happens mid-function. We don't need to set the hot - section alignment here, because code further down in this function - sets the alignment for whichever section comes first, and if there - is a hot section it is guaranteed to be first. */ + /* Make sure the not and cold text (code) sections are properly + aligned. This is necessary here in the case where the function + has both hot and cold sections, because we don't want to re-set + the alignment when the section switch happens mid-function. */ if (flag_reorder_blocks_and_partition) { unlikely_text_section (); assemble_align (FUNCTION_BOUNDARY); + ASM_OUTPUT_LABEL (asm_out_file, unlikely_section_label); + if (BB_PARTITION (ENTRY_BLOCK_PTR->next_bb) == BB_COLD_PARTITION) + { + /* Since the function starts with a cold section, we need to + explicitly align the hot section and write out the hot + section label. */ + text_section (); + assemble_align (FUNCTION_BOUNDARY); + ASM_OUTPUT_LABEL (asm_out_file, hot_section_label); + hot_label_written = true; + first_function_block_is_cold = true; + } } + else if (DECL_SECTION_NAME (decl)) + { + /* Calls to function_section rely on first_function_block_is_cold + being accurate. The first block may be cold even if we aren't + doing partitioning, if the entire function was decided by + choose_function_section (predict.c) to be cold. */ + + int i; + int len; + char *s; + initialize_cold_section_name (); + + /* The following is necessary, because 'strcmp + (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)), blah)' always + fails, presumably because TREE_STRING_POINTER is declared to + be an array of size 1 of char. */ + + len = TREE_STRING_LENGTH (DECL_SECTION_NAME (decl)); + s = (char *) xmalloc (len + 1); + + for (i = 0; i < len; i ++) + s[i] = (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)))[i]; + s[len] = '\0'; + + if (unlikely_text_section_name + && (strcmp (s, unlikely_text_section_name) == 0)) + first_function_block_is_cold = true; + } + + last_text_section = no_section; + in_section = no_section; resolve_unique_section (decl, 0, flag_function_sections); + + /* Switch to the correct text section for the start of the function. */ + function_section (decl); + if (!hot_label_written) + ASM_OUTPUT_LABEL (asm_out_file, hot_section_label); /* Tell assembler to move to target machine's alignment for functions. */ align = floor_log2 (FUNCTION_BOUNDARY / BITS_PER_UNIT); @@ -1288,12 +1357,7 @@ assemble_start_function (tree decl, const char *fnname) ASM_OUTPUT_LABEL (asm_out_file, fnname); #endif /* ASM_DECLARE_FUNCTION_NAME */ - if (in_unlikely_text_section () - && !unlikely_section_label_printed) - { - ASM_OUTPUT_LABEL (asm_out_file, unlikely_section_label); - unlikely_section_label_printed = true; - } + insert_section_boundary_note (); } /* Output assembler code associated with defining the size of the @@ -1302,6 +1366,7 @@ assemble_start_function (tree decl, const char *fnname) void assemble_end_function (tree decl, const char *fnname) { + enum in_section save_text_section; #ifdef ASM_DECLARE_FUNCTION_SIZE ASM_DECLARE_FUNCTION_SIZE (asm_out_file, fnname, decl); #endif @@ -1310,6 +1375,15 @@ assemble_end_function (tree decl, const char *fnname) output_constant_pool (fnname, decl); function_section (decl); /* need to switch back */ } + /* Output labels for end of hot/cold text sections (to be used by + debug info.) */ + save_text_section = in_section; + unlikely_text_section (); + ASM_OUTPUT_LABEL (asm_out_file, cold_section_end_label); + text_section (); + ASM_OUTPUT_LABEL (asm_out_file, hot_section_end_label); + if (save_text_section == in_unlikely_executed_text) + unlikely_text_section (); } /* Assemble code to leave SIZE bytes of zeros. */ |